1
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Jarma D, Maestre JP, Sanchez J, Brodfuehrer S, Katz LE, Horner S, Kinney KA. Participant-collected household dust for assessing microorganisms and semi-volatile organic compounds in urban homes. Sci Total Environ 2024; 908:168230. [PMID: 37951260 DOI: 10.1016/j.scitotenv.2023.168230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 10/17/2023] [Accepted: 10/28/2023] [Indexed: 11/13/2023]
Abstract
Dust samples collected by researchers and study participants from 43 U.S. urban homes were analyzed and compared to evaluate the feasibility of using participant-collected samples to assess indoor environmental exposures. The microbial and chemical composition of participant-collected (and shipped) samples were compared to researcher-collected samples from the same household, using dust recovered from each home's heating, ventilation, and air conditioning (HVAC) filter. The bacterial and fungal communities present in all dust samples were determined via MiSeq 16S and ITS sequencing, and the concentrations of 27 semi-volatile organic compounds (7 orthophosphates, 6 phthalates, and 14 brominated flame retardants) were determined via GC-MS. Self-report data on the home environment was collected via an online survey of study participants. While the researcher-collected samples (RCS) yielded greater mass than the participant-collected samples (PCS), the alpha and beta diversities of the bacterial and fungal communities recovered in the RCS and PCS were not significantly different, indicating that PCS is a viable option for indoor microbiome studies of residential homes. The microbial communities recovered in both cases reflected the dominance of human-associated bacterial taxa and outdoor-associated fungal taxa with similar pathogen-associated taxa present in each sample type. In both PCS and RCS, the amount of carpet in the home and the frequency of bleach use had a significant effect on the composition of fungal communities. Semi-volatile organic compounds (SVOCs) of potential human health concern, were commonly detected in the homes. Organophosphates and phthalates were recovered at a similar frequency in both PCS and RCS. Measured SVOC concentration levels were consistent with previous indoor studies although differences were observed between PCS and RCS for several SVOCs. This study demonstrates the potential and challenges associated with participant-collected dust samples for indoor environment studies.
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Affiliation(s)
- D Jarma
- Department of Civil, Architectural, and Environmental Engineering, The University of Texas at Austin, TX, USA
| | - J P Maestre
- Department of Civil, Architectural, and Environmental Engineering, The University of Texas at Austin, TX, USA
| | - J Sanchez
- School of Social Work, The University of Texas at Austin, TX, USA
| | - S Brodfuehrer
- Department of Civil, Architectural, and Environmental Engineering, The University of Texas at Austin, TX, USA
| | - L E Katz
- Department of Civil, Architectural, and Environmental Engineering, The University of Texas at Austin, TX, USA
| | - S Horner
- School of Nursing, The University of Texas at Austin, TX, USA
| | - K A Kinney
- Department of Civil, Architectural, and Environmental Engineering, The University of Texas at Austin, TX, USA.
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2
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Oden CP, Werth CJ, Kienzle BA, Katz LE. Impact of organic matter on transformation during thermal remediation of pyrene-contaminated substrates. Sci Total Environ 2024; 906:167569. [PMID: 37793444 DOI: 10.1016/j.scitotenv.2023.167569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 09/29/2023] [Accepted: 10/01/2023] [Indexed: 10/06/2023]
Abstract
Thermal remediation (TR) is a broadly applicable technology that is effective at removing volatile and semi-volatile contaminants from soil. However, TR can be costly and inefficient in practice, with underlying removal and transformation mechanisms poorly understood. To better understand the role organic matter plays in removal, a series of experiments was performed with a humic substance, humic modified silica, and a natural soil in the presence of pyrene from 100 to 500 °C and compared to prior experiments using pure minerals. Detection of by-products confirmed that pyrene was removed by transformation in addition to volatilization. Oxidation via hydroxyl radical formation and reductive hydrogenation were both indicated as possible reaction mechanisms promoted by organic matter. Because the presence of bulk water did not impact the extent of pyrene degradation or transformation, it is hypothesized that hydroxyl radicals were produced from soil organic matter functional groups, such as carboxyl and phenol groups, and possibly bound water at elevated temperatures in dry experiments. Additionally, the average oxidation state of carbon in detected by-products increased with temperature in experiments with humic modified silica and soil but not humic substance alone, though the extent of degradation did not significantly change. This shift in oxidation state may indicate that attachment of organic matter to another surface may increase interaction between reactive species. The results of this study show that contaminant transformation in soils during TR significantly contributes to removal, even at temperatures lower than those used in traditional treatment. This information will help to guide the design and operation of TR systems, potentially reducing energy requirements and highlighting the necessity of testing for transformation by-products.
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Affiliation(s)
- Cameron P Oden
- Department of Civil, Architectural, and Environmental Engineering, University of Texas at Austin, 301 E Dean Keeton St, Austin, TX, USA.
| | - Charles J Werth
- Department of Civil, Architectural, and Environmental Engineering, University of Texas at Austin, 301 E Dean Keeton St, Austin, TX, USA.
| | - Benjamin A Kienzle
- Department of Civil, Architectural, and Environmental Engineering, University of Texas at Austin, 301 E Dean Keeton St, Austin, TX, USA.
| | - Lynn E Katz
- Department of Civil, Architectural, and Environmental Engineering, University of Texas at Austin, 301 E Dean Keeton St, Austin, TX, USA.
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3
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Paspureddi A, Zhang Z, Ganesan V, Sharma MM, Katz LE. Mechanism of monovalent and divalent ion mobility in Nafion membrane: An atomistic simulation study. J Chem Phys 2023; 158:2894004. [PMID: 37265217 DOI: 10.1063/5.0145205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 05/11/2023] [Indexed: 06/03/2023] Open
Abstract
Polymer cation exchange membranes (CEMs) are widely used in water treatment processes. The fundamental factors that control the separation and selectivity of cations with different valences in CEMs are not fully understood. In this study, we use atomistic molecular dynamics simulations to investigate the underlying molecular mechanisms that control the mobility of cations with different valences in Nafion membranes. Our results indicate structural differences in binding of monovalent and divalent cations, which gives rise to differences in ion diffusion in Nafion. Monovalent cations are shown to be "territorially" bound, i.e., bound while partially hydrated, to the fixed charge groups whereas divalent cations are shown to be "site" bound, i.e., bound while fully dehydrated, to the charge groups on the polymer. This difference in binding structure gives rise to differences in transport characteristics of cations in Nafion.
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Affiliation(s)
- Akhilesh Paspureddi
- McKetta Department of Chemical Engineering, The University of Texas at Austin, 200 E. Dean Keeton Street, Austin, Texas 78712, USA
| | - Zidan Zhang
- McKetta Department of Chemical Engineering, The University of Texas at Austin, 200 E. Dean Keeton Street, Austin, Texas 78712, USA
| | - Venkat Ganesan
- McKetta Department of Chemical Engineering, The University of Texas at Austin, 200 E. Dean Keeton Street, Austin, Texas 78712, USA
| | - Mukul M Sharma
- McKetta Department of Chemical Engineering, The University of Texas at Austin, 200 E. Dean Keeton Street, Austin, Texas 78712, USA
| | - Lynn E Katz
- Department of Civil, Architectural, and Environmental Engineering, The University of Texas at Austin, 301 E. Dean Keeton Street, Austin, Texas 78712, USA
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4
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Han J, Nomaan SM, Katz LE. Prediction of alkaline earth metal ion adsorption on goethite for various background electrolytes with the CD-MUSIC model. Sci Total Environ 2023:164462. [PMID: 37263441 DOI: 10.1016/j.scitotenv.2023.164462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Revised: 05/22/2023] [Accepted: 05/23/2023] [Indexed: 06/03/2023]
Abstract
As water scarcity drives the use of more saline water sources, contaminant fate and transport models must capture the impact of high concentrations of alkaline earth metal ions (AEMs) and background electrolytes in these more complex waters. By utilizing macroscopic adsorption data from various electrolyte systems, a Charge Distribution - Multisite Complexation (CD-MUSIC) model, capable of incorporating electrolyte adsorption, was able to accurately simulate the adsorption behavior of alkaline earth metal ions onto goethite. The modeling effort was guided by previous spectroscopic and surface complexation modeling of alkaline earth metal adsorption and built on previous CD-MUSIC modeling that accounted for changes in crystal face contributions to the surface site density as a function of specific surface area. The model was constrained to consider only two dominant surface complex species for each metal ion adsorption reaction. These two species were selected from 44 possible species through objective curve fitting of single-solute macroscopic adsorption data. While most of the alkaline earth metal surface complexes formed outer-sphere complexes at the goethite surface, an inner-sphere species was utilized for Mg2+. With the surface complex species and equilibrium constants obtained from this study, the calibrated model successfully predicted alkaline earth metal ion adsorption over a wide range of solution and surface conditions; the model predictions encompassed a wide range of pH (5-11), solute/solid ratio (1.37 × 10-5-8.33 × 10-4 mol-solute/g-solid), ionic strengths (0.01 M - 0.7 M), and background electrolytes (Na+, Cs+, Rb+, Cl-, and NO3-) using the same crystal face contribution methodology for site density, capacitance values, and surface acidity constants adopted for proton and cadmium adsorption in previous work (Han and Katz, 2019). Model simulations for a range of background water chemistries demonstrated the potential for Mg2+ to reduce Cd2+ adsorption to goethite in model seawater and oil- and gas-produced waters.
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Affiliation(s)
- Joonkyoung Han
- The University of Texas at Austin, Department of Civil, Architectural and Environmental Engineering, 301 E. Dean Keeton St. C1786, Austin, TX 78712, USA
| | - Sheik Mohammad Nomaan
- The University of Texas at Austin, Department of Civil, Architectural and Environmental Engineering, 301 E. Dean Keeton St. C1786, Austin, TX 78712, USA
| | - Lynn E Katz
- The University of Texas at Austin, Department of Civil, Architectural and Environmental Engineering, 301 E. Dean Keeton St. C1786, Austin, TX 78712, USA.
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5
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Sujanani R, Nordness O, Miranda A, Katz LE, Brennecke JF, Freeman BD. Accounting for Ion Pairing Effects on Sulfate Salt Sorption in Cation Exchange Membranes. J Phys Chem B 2023; 127:1842-1855. [PMID: 36795084 DOI: 10.1021/acs.jpcb.2c07900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Ion exchange membranes (IEMs) are frequently used in water treatment and electrochemical applications, with their ion separation properties largely governed by equilibrium ion partitioning between a membrane and contiguous solution. Despite an expansive literature on IEMs, the influence of electrolyte association (i.e., ion pairing) on ion sorption remains relatively unexplored. In this study, salt sorption in two commercial cation exchange membranes equilibrated with 0.01-1.0 M MgSO4 and Na2SO4 is investigated experimentally and theoretically. Association measurements of salt solutions using conductometric experiments and the Stokes-Einstein approximation show significant concentrations of ion pairs in MgSO4 and Na2SO4 relative to those in simple electrolytes (i.e., NaCl), which is consistent with prior studies of sulfate salts. The Manning/Donnan model, developed and validated for halide salts in previous studies, substantially underpredicts sulfate sorption measurements, presumably due to ion pairing effects not accounted for in this established theory. These findings suggest that ion pairing can enhance salt sorption in IEMs due to partitioning of reduced valence species. By reformulating the Donnan and Manning models, a theoretical framework for predicting salt sorption in IEMs that explicitly considers electrolyte association is developed. Remarkably, theoretical predictions of sulfate sorption are improved by over an order of magnitude by accounting for ion speciation. In some cases, good quantitative agreement is observed between theoretical and experimental values for external salt concentrations between 0.1 and 1.0 M using no adjustable parameters.
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Affiliation(s)
- Rahul Sujanani
- McKetta Department of Chemical Engineering, The University of Texas at Austin, 200 E. Dean Keeton Street, Austin, Texas 78712, United States
| | - Oscar Nordness
- McKetta Department of Chemical Engineering, The University of Texas at Austin, 200 E. Dean Keeton Street, Austin, Texas 78712, United States
| | - Andres Miranda
- McKetta Department of Chemical Engineering, The University of Texas at Austin, 200 E. Dean Keeton Street, Austin, Texas 78712, United States
| | - Lynn E Katz
- Department of Civil, Architectural, and Environmental Engineering, The University of Texas at Austin, 301 E. Dean Keeton Street, Austin, Texas 78712, United States
| | - Joan F Brennecke
- McKetta Department of Chemical Engineering, The University of Texas at Austin, 200 E. Dean Keeton Street, Austin, Texas 78712, United States
| | - Benny D Freeman
- McKetta Department of Chemical Engineering, The University of Texas at Austin, 200 E. Dean Keeton Street, Austin, Texas 78712, United States
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6
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Jiao S, Katz LE, Shell MS. Inverse Design of Pore Wall Chemistry To Control Solute Transport and Selectivity. ACS Cent Sci 2022; 8:1609-1617. [PMID: 36589891 PMCID: PMC9801506 DOI: 10.1021/acscentsci.2c01011] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Indexed: 05/08/2023]
Abstract
Next-generation membranes for purification and reuse of highly contaminated water require materials with precisely tuned functionality to address key challenges, including the removal of small, charge-neutral solutes. Bioinspired multifunctional membrane surfaces enhance transport properties, but the combinatorically large chemical space is difficult to navigate through trial and error. Here, we demonstrate a computational inverse design approach to efficiently identify promising materials and elucidate design rules. We develop a combined evolutionary optimization, machine learning, and molecular simulation workflow to spatially design chemical functional group patterning in a model nanopore that enhances transport of water relative to solutes. The genetic optimization discovers nonintuitive functionalization strategies that hinder the transport of solutes through the pore, simply by patterning hydrophobic methyl and hydrophilic hydroxyl functional groups. Examining these patterns, we demonstrate that they exploit an unexpected diffusive solute hopping mechanism. This inverse design procedure and the identification of novel molecular mechanisms for pore chemical heterogeneity to impact solute selectivity demonstrate new routes to the design of membrane materials with novel functionalities. More broadly, this work illustrates how chemical design is a powerful strategy to modulate water-mediated surface-solute interactions in complex, soft material systems that are relevant to diverse technologies.
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Affiliation(s)
- Sally Jiao
- Department
of Chemical Engineering, University of California, Santa Barbara, California93106, United States
| | - Lynn E. Katz
- Department
of Civil, Architectural and Environmental Engineering, University of Texas at Austin, Austin, Texas78712, United States
| | - M. Scott Shell
- Department
of Chemical Engineering, University of California, Santa Barbara, California93106, United States
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7
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Aydogan Gokturk P, Sujanani R, Qian J, Wang Y, Katz LE, Freeman BD, Crumlin EJ. The Donnan potential revealed. Nat Commun 2022; 13:5880. [PMID: 36202843 PMCID: PMC9537300 DOI: 10.1038/s41467-022-33592-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 09/22/2022] [Indexed: 11/13/2022] Open
Abstract
Selective transport of solutes across a membrane is critical for many biological, water treatment and energy conversion and storage systems. When a charged membrane is equilibrated with an electrolyte, an unequal distribution of ions arises between phases, generating the so-called Donnan electrical potential at the solution/membrane interface. The Donnan potential results in the partial exclusion of co-ion, providing the basis of permselectivity. Although there are well-established ways to indirectly estimate the Donnan potential, it has been widely reported that it cannot be measured directly. Here we report the first direct measurement of the Donnan potential of an ion exchange membrane equilibrated with salt solutions. Our results highlight the dependence of the Donnan potential on external salt concentration and counter-ion valence, and show a reasonable agreement with current theoretical models of IEMs, which incorporate ion activity coefficients. By directly measuring the Donnan potential, we eliminate ambiguities that arise from limitations inherent in current models. Donnan electrical potential is widely adopted to describe ion distribution between two solutions separated by a permeable membrane with implications for many chemical and biological systems. Aydogan Gokturk et al. directly measures this potential for the first time and compare the data with theoretical models.
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Affiliation(s)
- Pinar Aydogan Gokturk
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Rahul Sujanani
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Jin Qian
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.,Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Ye Wang
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.,Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Lynn E Katz
- Department of Civil, Architectural, and Environmental Engineering, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Benny D Freeman
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Ethan J Crumlin
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA. .,Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
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8
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Paspureddi A, Sharma MM, Katz LE. Effect of Dielectric Saturation on Ion Activity Coefficients in Ion Exchange Membranes. ACS Omega 2022; 7:30823-30834. [PMID: 36092628 PMCID: PMC9453797 DOI: 10.1021/acsomega.2c02258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 08/02/2022] [Indexed: 06/15/2023]
Abstract
Polymeric ion exchange membranes are used in water purification processes to separate ions from water. The distribution and transport of ionic species through these membranes depend on a variety of factors, including membrane charge density, morphology, chemical structure, and the specific ionic species present in the fluid. The electrical potential distribution between membranes and solutions is typically described using models based on Donnan theory. An extension of the original theory is proposed to account for the nonideal behavior of ions both in the fluid and in the membrane as well to provide a more robust description of interactions of solutes with fixed charge groups on the polymer backbone. In this study, the variation in dielectric permittivity in the membrane medium with electric field strength is taken into account in a model based on Gouy-Chapman double-layer theory to provide a more accurate description of ion activity coefficients in an ion exchange membrane. A semianalytical model is presented that accounts for the variation in dielectric permittivity of water in a charged polymer membrane. A comparison of this model with Manning's counterion condensation model clearly demonstrates that by incorporating changes in water dielectric permittivity with electric field strength, much better agreement with experiments can be obtained over a range of salt concentrations for different ions.
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Affiliation(s)
- Akhilesh Paspureddi
- The
University of Texas at Austin, Department of Chemical Engineering, Austin, Texas 78712, United States
| | - Mukul M. Sharma
- The
University of Texas at Austin, Department of Chemical Engineering, Austin, Texas 78712, United States
- The
University of Texas at Austin, Department
of Petroleum and Geosystems Engineering, Austin, Texas 78712, United States
| | - Lynn E. Katz
- The
University of Texas at Austin, Department
of Civil, Architectural, and Environmental Engineering, Austin, Texas 78712, United States
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9
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Oden CP, Werth CJ, Notini L, Katz LE. Fate of pyrene on mineral surfaces during thermal remediation as a function of temperature. Environ Sci Process Impacts 2022; 24:1181-1194. [PMID: 35766907 DOI: 10.1039/d2em00027j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
There is evidence that contaminants can transform at the elevated temperatures of thermal remediation; however, the contribution of redox active minerals to transformation has not been investigated. Three redox active minerals (i.e., birnessite (MnO2), magnetite (Fe3O4), and hematite (Fe2O3)) and one redox inactive mineral (Ottawa sand (SiO2)) were spiked with pyrene and thermally treated. Under dry, anoxic conditions, 100%, 75% ± 3%, 70% ± 15%, and 14% ± 28% of the initial pyrene mass was removed with birnessite, magnetite, hematite, and Ottawa sand, respectively, after treatment at 250 °C for 30 min. Under wet, oxic conditions, 92% ± 8%, 86% ± 12%, 79% ± 4%, and 42% ± 7% was removed for the same minerals, respectively, after treatment at only 150 °C for 30 min. Baseline studies with Ottawa sand resulted in volatilization alone of pyrene with no transformation observed. Increased pyrene loading was used to evaluate potential transformation pathways based on identified by-products, demonstrating that both oxidative and reductive pathways were operative depending on the conditions. Reaction products in the presence of redox active minerals indicate transformation was dominated by reduction via hydrogenation in dry experiments, and by oxidation via hydroxyl radicals in wet experiments. The latter was unexpected, because only low hydroxyl radical concentrations have been detected in mineral-water systems at ambient temperature. These results indicate that understanding dominant reaction pathways and products is advantageous for the design of efficient and safe thermally enhanced treatment systems.
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Affiliation(s)
- Cameron P Oden
- University of Texas at Austin, USA
- University of Colorado Boulder, USA.
| | | | - Luiza Notini
- University of Texas at Austin, USA
- ETH Zurich, Switzerland
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10
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Brodfuehrer SH, Goodman JB, Wahman DG, Speitel GE, Katz LE. Apparent Reactivity of Bromine in Bromochloramine Depends on Synthesis Method: Implicating Bromine Chloride and Molecular Bromine as Important Bromine Species. J Environ Eng (New York) 2022; 148:10.1061/(asce)ee.1943-7870.0002070. [PMID: 36337256 PMCID: PMC9628185 DOI: 10.1061/(asce)ee.1943-7870.0002070] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 07/11/2022] [Indexed: 06/16/2023]
Abstract
The chloramination of bromide containing waters results in the formation of bromine containing haloamines: monobromamine (NH2Br), dibromamine (NHBr2), and bromochloramine (NHBrCl). Many studies have directly shown that bromamines are more reactive than chloramines in oxidation and substitution reactions with organic water constituents because the bromine atom in oxidants is more labile than the chlorine atom. However, similar studies have not been performed with NHBrCl. It has been assumed that NHBrCl has similar reactivity as bromamines with organic constituents in both oxidation and substitution reactions because NHBrCl, like bromamines, rapidly oxidizes N,N-diethyl-p-phenylenediamine. In this study, we examined the reactivity of NHBrCl with phenol red to determine if NHBrCl reacts as readily as bromamines in an isolated substitution reaction. NHBrCl was synthesized two ways to assess whether NHBrCl or the highly reactive intermediates, bromine chloride (BrCl) and molecular bromine (Br2), were responsible for bromine substitution of phenol red. NHBrCl was found to be much less reactive than bromamines with phenol red and that BrCl and Br2 appeared to be the true brominating agents in solutions where NHBrCl is formed. This work highlights the need to reexamine what the true brominating agents are in chloraminated waters containing bromide.
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Affiliation(s)
- Samuel H Brodfuehrer
- Graduate Student, Dept. of Civil, Architectural, and Environmental Engineering, Univ. of Texas at Austin, 301 E. Dean Keaton St., Stop C1786, Austin, TX 78712-0284
| | - Jacob B Goodman
- Graduate Student, Dept. of Civil, Architectural, and Environmental Engineering, Univ. of Texas at Austin, 301 E. Dean Keaton St., Stop C1786, Austin, TX 78712-0284
| | - David G Wahman
- Research Environmental Engineer, United States Environmental Protection Agency, Office of Research and Development, 26 W MLK Dr., Cincinnati, OH 45268
| | - Gerald E Speitel
- Professor and Associate Dean of Academic Affairs, Dept. of Civil, Architectural, and Environmental Engineering, Univ. of Texas at Austin, 301 E. Dean Keaton St., Stop C1786, Austin, TX 78712-0284
| | - Lynn E Katz
- Professor, Dept. of Civil, Architectural, and Environmental Engineering, Univ. of Texas at Austin, 301 E. Dean Keaton St., Stop C1786, Austin, TX 78712-0284
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11
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Spearing L, Tiedmann HR, Sela L, Nagy Z, Kaminsky JA, Katz LE, Kinney KA, Kirisits MJ, Faust KM. Human-Infrastructure Interactions during the COVID-19 Pandemic: Understanding Water and Electricity Demand Profiles at the Building Level. ACS ES T Water 2021; 1:2327-2338. [PMID: 34778873 PMCID: PMC8577189 DOI: 10.1021/acsestwater.1c00176] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 10/14/2021] [Accepted: 10/15/2021] [Indexed: 06/13/2023]
Abstract
When engineers design and manage a building's water and electricity utilities, they must make assumptions about resource use. These assumptions are often challenged when unexpected changes in demand occur, such as the spatial and temporal changes observed during the coronavirus (COVID-19) pandemic. Social distancing policies (SDPs) enacted led many universities to close their campuses and implement remote learning, impacting utility consumption patterns. Yet, little is known about how consumption changed at the building level. Here, we aim to understand how water and electricity consumption changed during the pandemic by identifying characteristic weekly demand profiles and understanding how these changes were related to regulatory and social systems. We performed k-means clustering on utility demand data measured before and as the pandemic evolved from five buildings of different types at the University of Texas at Austin. As expected, after SDPs were enacted both water and electricity use shifted, with most buildings seeing a sharp initial decline that remained low until the university partially reopened. In contrast to electricity use, we found that water use was tightly coupled with SDPs. Our study provides actionable information for managers to mitigate negative impacts (e.g., water stagnation) and capitalize on opportunities to minimize resource use.
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Affiliation(s)
- Lauryn
A. Spearing
- Civil,
Architectural and Environmental Engineering, The University of Texas at Austin, 301 Dean Keeton C1752, Austin, Texas 78751, United States
| | - Helena R. Tiedmann
- Civil,
Architectural and Environmental Engineering, The University of Texas at Austin, 301 Dean Keeton C1752, Austin, Texas 78751, United States
| | - Lina Sela
- Civil,
Architectural and Environmental Engineering, The University of Texas at Austin, 301 Dean Keeton C1752, Austin, Texas 78751, United States
| | - Zoltan Nagy
- Civil,
Architectural and Environmental Engineering, The University of Texas at Austin, 301 Dean Keeton C1752, Austin, Texas 78751, United States
| | - Jessica A. Kaminsky
- Civil
and Environmental Engineering, The University
of Washington, 3760 E. Stevens Way NE, Seattle, Washington 98195, United States
| | - Lynn E. Katz
- Civil,
Architectural and Environmental Engineering, The University of Texas at Austin, 301 Dean Keeton C1752, Austin, Texas 78751, United States
| | - Kerry A. Kinney
- Civil,
Architectural and Environmental Engineering, The University of Texas at Austin, 301 Dean Keeton C1752, Austin, Texas 78751, United States
| | - Mary Jo Kirisits
- Civil,
Architectural and Environmental Engineering, The University of Texas at Austin, 301 Dean Keeton C1752, Austin, Texas 78751, United States
| | - Kasey M. Faust
- Civil,
Architectural and Environmental Engineering, The University of Texas at Austin, 301 Dean Keeton C1752, Austin, Texas 78751, United States
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12
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Sujanani R, Katz LE, Paul DR, Freeman BD. Aqueous ion partitioning in Nafion: Applicability of Manning's counter-ion condensation theory. J Memb Sci 2021. [DOI: 10.1016/j.memsci.2021.119687] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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13
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Landsman MR, Rivers F, Pedretti BJ, Freeman BD, Lawler DF, Lynd NA, Katz LE. Boric acid removal with polyol-functionalized polyether membranes. J Memb Sci 2021. [DOI: 10.1016/j.memsci.2021.119690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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14
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Kim KT, Jagannath MSP, Su GM, Freychet G, Zeng T, Mohanty KK, Henkelman G, Katz LE, Werth CJ. Surfactant inhibition mechanisms of carbonate mineral dissolution in shale. Colloids Surf A Physicochem Eng Asp 2021. [DOI: 10.1016/j.colsurfa.2021.126857] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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15
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Spearing LA, Thelemaque N, Kaminsky JA, Katz LE, Kinney KA, Kirisits MJ, Sela L, Faust KM. Implications of Social Distancing Policies on Drinking Water Infrastructure: An Overview of the Challenges to and Responses of U.S. Utilities during the COVID-19 Pandemic. ACS ES T Water 2021; 1:888-899. [PMID: 37607034 PMCID: PMC7805597 DOI: 10.1021/acsestwater.0c00229] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 12/18/2020] [Accepted: 12/21/2020] [Indexed: 05/04/2023]
Abstract
Social distancing policies (SDPs) implemented throughout the United States in response to COVID-19 have led to spatial and temporal shifts in drinking water demand and, for water utilities, created sociotechnical challenges. During this unique period, many water utilities have been forced to operate outside of design conditions with reduced workforce and financial capacities. Few studies have examined how water utilities respond to a pandemic; such methods are even absent from many emergency response plans. Here, we documented how utilities have been impacted by the COVID-19 pandemic. We conducted a qualitative analysis of 30 interviews with 53 practitioners spanning 28 U.S. water utilities. Our aim was to, first, understand the challenges experienced by utilities and changes to operations (e.g., demand and deficit accounts) and, second, to document utilities' responses. Results showed that to maintain service continuity and implement SDPs, utilities had to overcome various challenges. These include supply chain issues, spatiotemporal changes in demand, and financial losses, and these challenges were largely dependent on the type of customers served (e.g., commercial or residential). Examples of utilities' responses include proactively ordering extra supplies and postponing capital projects. Although utilities' adaptations ensured the immediate provision of water services, their responses might have negative repercussions in the future (e.g., delayed projects contributing to aging infrastructure).
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Affiliation(s)
- Lauryn A. Spearing
- Civil, Architectural and Environmental Engineering,
The University of Texas at Austin, 301 Dean Keeton C1752,
Austin, Texas 78751, United States
| | - Nathalie Thelemaque
- Civil and Environmental Engineering, The
University of Washington, 3760 East Stevens Way Northeast, Seattle,
Washington 98195, United States
| | - Jessica A. Kaminsky
- Civil and Environmental Engineering, The
University of Washington, 3760 East Stevens Way Northeast, Seattle,
Washington 98195, United States
| | - Lynn E. Katz
- Civil, Architectural and Environmental Engineering,
The University of Texas at Austin, 301 Dean Keeton C1752,
Austin, Texas 78751, United States
| | - Kerry A. Kinney
- Civil, Architectural and Environmental Engineering,
The University of Texas at Austin, 301 Dean Keeton C1752,
Austin, Texas 78751, United States
| | - Mary Jo Kirisits
- Civil, Architectural and Environmental Engineering,
The University of Texas at Austin, 301 Dean Keeton C1752,
Austin, Texas 78751, United States
| | - Lina Sela
- Civil, Architectural and Environmental Engineering,
The University of Texas at Austin, 301 Dean Keeton C1752,
Austin, Texas 78751, United States
| | - Kasey M. Faust
- Civil, Architectural and Environmental Engineering,
The University of Texas at Austin, 301 Dean Keeton C1752,
Austin, Texas 78751, United States
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Faust KM, Katz LE, Kirisits MJ, Kinney KA, Sela L, Kopytkovskiy M, Russell C, Kaminsky J. Consider How Social Distancing Policies Can Affect Drinking Water Infrastructure Performance. J Am Water Works Assoc 2021; 113:74-77. [PMID: 33821012 PMCID: PMC8014058 DOI: 10.1002/awwa.1673] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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17
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Monroe JI, Jiao S, Davis RJ, Robinson Brown D, Katz LE, Shell MS. Affinity of small-molecule solutes to hydrophobic, hydrophilic, and chemically patterned interfaces in aqueous solution. Proc Natl Acad Sci U S A 2021; 118:e2020205118. [PMID: 33372161 PMCID: PMC7821046 DOI: 10.1073/pnas.2020205118] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Performance of membranes for water purification is highly influenced by the interactions of solvated species with membrane surfaces, including surface adsorption of solutes upon fouling. Current efforts toward fouling-resistant membranes often pursue surface hydrophilization, frequently motivated by macroscopic measures of hydrophilicity, because hydrophobicity is thought to increase solute-surface affinity. While this heuristic has driven diverse membrane functionalization strategies, here we build on advances in the theory of hydrophobicity to critically examine the relevance of macroscopic characterizations of solute-surface affinity. Specifically, we use molecular simulations to quantify the affinities to model hydroxyl- and methyl-functionalized surfaces of small, chemically diverse, charge-neutral solutes represented in produced water. We show that surface affinities correlate poorly with two conventional measures of solute hydrophobicity, gas-phase water solubility and oil-water partitioning. Moreover, we find that all solutes show attraction to the hydrophobic surface and most to the hydrophilic one, in contrast to macroscopically based hydrophobicity heuristics. We explain these results by decomposing affinities into direct solute interaction energies (which dominate on hydroxyl surfaces) and water restructuring penalties (which dominate on methyl surfaces). Finally, we use an inverse design algorithm to show how heterogeneous surfaces, with multiple functional groups, can be patterned to manipulate solute affinity and selectivity. These findings, importantly based on a range of solute and surface chemistries, illustrate that conventional macroscopic hydrophobicity metrics can fail to predict solute-surface affinity, and that molecular-scale surface chemical patterning significantly influences affinity-suggesting design opportunities for water purification membranes and other engineered interfaces involving aqueous solute-surface interactions.
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Affiliation(s)
- Jacob I Monroe
- Department of Chemical Engineering, University of California, Santa Barbara, CA 93106
| | - Sally Jiao
- Department of Chemical Engineering, University of California, Santa Barbara, CA 93106
| | - R Justin Davis
- Department of Civil, Architectural and Environmental Engineering, University of Texas at Austin, Austin, TX 78712
| | - Dennis Robinson Brown
- Department of Chemical Engineering, University of California, Santa Barbara, CA 93106
| | - Lynn E Katz
- Department of Civil, Architectural and Environmental Engineering, University of Texas at Austin, Austin, TX 78712
| | - M Scott Shell
- Department of Chemical Engineering, University of California, Santa Barbara, CA 93106;
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18
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Brodfuehrer SH, Wahman DG, Alsulaili A, Speitel GE, Katz LE. Role of Carbonate Species on General Acid Catalysis of Bromide Oxidation by Hypochlorous Acid (HOCl) and Oxidation by Molecular Chlorine (Cl 2). Environ Sci Technol 2020; 54:16186-16194. [PMID: 33263389 PMCID: PMC7891864 DOI: 10.1021/acs.est.0c04563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Kinetic models for disinfectant decay and disinfection byproduct (DBP) formation are necessary for predicting water quality from the treatment plant to the tap. A kinetic model for conditions relevant to chloramine disinfection of drinking water (pH 6-9 and carbonate-buffered) was developed to simulate incomplete bromide (Br-) oxidation during short prechlorination periods because it is the first step in a complex system of reactions that leads to disinfectant loss and DBP formation. Hypochlorous acid (HOCl+Br-→kHOClHOBr+Cl-) and molecular chlorine (Cl2+Br-+H2O→kCl2HOBr+2Cl-+H+) were the free chlorine species relevant to Br- oxidation, and Cl2 hydrolysis and formation reactions (Cl2+H2O+A-⇌k-4k4HOCl+HA+Cl-) were necessary to accurately simulate Cl2 concentrations instead of assuming equilibrium. Previous work has shown that Br- oxidation by HOCl and Cl2 formation are acid-catalyzed and Cl2 hydrolysis is base-catalyzed, but the impact of carbonate species had not been studied. This work showed that the carbonate species have an enhanced catalytic impact with rate constants up to 1000 times larger than would be estimated by the Brønsted relationship for similar acids, which causes the oxidation by HOCl rate constant (kHOCl) to nearly double and oxidation by Cl2 to occur above pH 7 in high-alkalinity waters.
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Affiliation(s)
- Samuel H Brodfuehrer
- Department of Civil, Architectural and Environmental Engineering, University of Texas at Austin, 301 E. Dean Keaton Street, Stop C1786, Austin, Texas 78712-0284, United States
| | - David G Wahman
- Office of Research and Development, United States Environmental Protection Agency, Cincinnati, Ohio 45268, United States
| | | | - Gerald E Speitel
- Department of Civil, Architectural and Environmental Engineering, University of Texas at Austin, 301 E. Dean Keaton Street, Stop C1786, Austin, Texas 78712-0284, United States
| | - Lynn E Katz
- Department of Civil, Architectural and Environmental Engineering, University of Texas at Austin, 301 E. Dean Keaton Street, Stop C1786, Austin, Texas 78712-0284, United States
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19
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Davis RJ, Liljestrand HM, Katz LE. Evidence for multiple removal pathways in low-temperature (200-400 °C) thermal treatment of pentachlorophenol-laden soils. J Hazard Mater 2020; 400:122870. [PMID: 32947725 DOI: 10.1016/j.jhazmat.2020.122870] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 04/28/2020] [Accepted: 04/29/2020] [Indexed: 06/11/2023]
Abstract
Polychlorinated aromatic compounds (PCACs) pose significant remediation challenges, since their high soil affinities preclude mobile-phase partitioning and subsurface extraction. To enhance partitioning and desorption, subsurface temperatures are raised using a technique called thermal conduction heating-soil vapor extraction (TCH-SVE). While this technique improves PCAC partitioning, it can also promote several degradation reactions under temperatures typical of low-temperature TCH-SVE (200-400 °C). While these reactions are labile, the extent to which they occur in flow-through TCH-SVE is unclear. The current research used bench-scale, flow-through TCH-SVE to assess relative importance of three removal pathways: (1) target volatilization, (2) reductive dechlorination, and (3) oxidation via OH-addition. Pentachlorophenol was used as a representative PCAC, and pathway contributions, extents, and regioselectivity were examined as a function of temperature (225-375 °C) and gas-phase oxygen content (air vs. nitrogen). Across treatments, OH-addition and dechlorination occurred in parallel and accounted for significantly more removal than PCP volatilization. OH-addition byproducts had highest yields (regardless of oxygen content) and were consistent with surface-mediated OH production and ring addition. OH-addition increased with temperature while volatilization and dechlorination decreased. Notable exceptions occurred between 225 and 325 °C (where dechlorination dropped 10-fold) and 325 and 375 °C (where OH-addition fell 75%), signifying major mechanism shifts in these intervals.
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Affiliation(s)
- R Justin Davis
- Center for Water and the Environment, The University of Texas at Austin, Austin, TX, USA.
| | - Howard M Liljestrand
- Center for Water and the Environment, The University of Texas at Austin, Austin, TX, USA.
| | - Lynn E Katz
- Center for Water and the Environment, The University of Texas at Austin, Austin, TX, USA.
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20
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Sujanani R, Landsman MR, Jiao S, Moon JD, Shell MS, Lawler DF, Katz LE, Freeman BD. Designing Solute-Tailored Selectivity in Membranes: Perspectives for Water Reuse and Resource Recovery. ACS Macro Lett 2020; 9:1709-1717. [PMID: 35617076 DOI: 10.1021/acsmacrolett.0c00710] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Treatment of nontraditional source waters (e.g., produced water, municipal and industrial wastewaters, agricultural runoff) offers exciting opportunities to expand water and energy resources via water reuse and resource recovery. While conventional polymer membranes perform water/ion separations well, they do not provide solute-specific separation, a key component for these treatment opportunities. Herein, we discuss the selectivity limitations plaguing all conventional membranes, which include poor removal of small, neutral solutes and insufficient discrimination between ions of the same valence. Moreover, we present synthetic approaches for solute-tailored selectivity including the incorporation of single-digit nanopores and solute-selective ligands into membranes. Recent progress in these areas highlights the need for fundamental studies to rationally design membranes with selective moieties achieving desired separations.
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Affiliation(s)
- Rahul Sujanani
- McKetta Department of Chemical Engineering, The University of Texas at Austin, 200 East Dean Keeton Street, Austin, Texas 78712, United States
| | - Matthew R. Landsman
- Department of Civil, Architectural, and Environmental Engineering, The University of Texas at Austin, 301 East Dean Keeton Street, Austin, Texas 78712, United States
| | - Sally Jiao
- Department of Chemical Engineering, The University of California Santa Barbara, 3357 Engineering II, Santa Barbara, California 93106, United States
| | - Joshua D. Moon
- Department of Chemical Engineering, The University of California Santa Barbara, 3357 Engineering II, Santa Barbara, California 93106, United States
| | - M. Scott Shell
- Department of Chemical Engineering, The University of California Santa Barbara, 3357 Engineering II, Santa Barbara, California 93106, United States
| | - Desmond F. Lawler
- Department of Civil, Architectural, and Environmental Engineering, The University of Texas at Austin, 301 East Dean Keeton Street, Austin, Texas 78712, United States
| | - Lynn E. Katz
- Department of Civil, Architectural, and Environmental Engineering, The University of Texas at Austin, 301 East Dean Keeton Street, Austin, Texas 78712, United States
| | - Benny D. Freeman
- McKetta Department of Chemical Engineering, The University of Texas at Austin, 200 East Dean Keeton Street, Austin, Texas 78712, United States
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21
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22
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Landsman MR, Sujanani R, Brodfuehrer SH, Cooper CM, Darr AG, Davis RJ, Kim K, Kum S, Nalley LK, Nomaan SM, Oden CP, Paspureddi A, Reimund KK, Rowles LS, Yeo S, Lawler DF, Freeman BD, Katz LE. Water Treatment: Are Membranes the Panacea? Annu Rev Chem Biomol Eng 2020; 11:559-585. [DOI: 10.1146/annurev-chembioeng-111919-091940] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Alongside the rising global water demand, continued stress on current water supplies has sparked interest in using nontraditional source waters for energy, agriculture, industry, and domestic needs. Membrane technologies have emerged as one of the most promising approaches to achieve water security, but implementation of membrane processes for increasingly complex waters remains a challenge. The technical feasibility of membrane processes replacing conventional treatment of alternative water supplies (e.g., wastewater, seawater, and produced water) is considered in the context of typical and emerging water quality goals. This review considers the effectiveness of current technologies (both conventional and membrane based), as well as the potential for recent advancements in membrane research to achieve these water quality goals. We envision the future of water treatment to integrate advanced membranes (e.g., mixed-matrix membranes, block copolymers) into smart treatment trains that achieve several goals, including fit-for-purpose water generation, resource recovery, and energy conservation.
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Affiliation(s)
- Matthew R. Landsman
- Department of Civil, Architectural, and Environmental Engineering, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Rahul Sujanani
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Samuel H. Brodfuehrer
- Department of Civil, Architectural, and Environmental Engineering, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Carolyn M. Cooper
- Department of Civil, Architectural, and Environmental Engineering, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Addison G. Darr
- Department of Civil, Architectural, and Environmental Engineering, The University of Texas at Austin, Austin, Texas 78712, USA
| | - R. Justin Davis
- Department of Civil, Architectural, and Environmental Engineering, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Kyungtae Kim
- Department of Civil, Architectural, and Environmental Engineering, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Soyoon Kum
- Department of Civil, Architectural, and Environmental Engineering, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Lauren K. Nalley
- Department of Civil, Architectural, and Environmental Engineering, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Sheik M. Nomaan
- Department of Civil, Architectural, and Environmental Engineering, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Cameron P. Oden
- Department of Civil, Architectural, and Environmental Engineering, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Akhilesh Paspureddi
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Kevin K. Reimund
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Lewis Stetson Rowles
- Department of Civil, Architectural, and Environmental Engineering, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Seulki Yeo
- Department of Civil, Architectural, and Environmental Engineering, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Desmond F. Lawler
- Department of Civil, Architectural, and Environmental Engineering, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Benny D. Freeman
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Lynn E. Katz
- Department of Civil, Architectural, and Environmental Engineering, The University of Texas at Austin, Austin, Texas 78712, USA
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23
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Abstract
The role of calcite heterogeneous nucleation was studied in a particle-coagulation treatment process for removing microalgae from water. Batch experiments were conducted with Scenedesmus sp. and Chlorella sp. in the presence and absence of carbonate and in the presence and absence of magnesium to delineate the role of CaCO3(S) nucleation on microalgae removal. The results indicate that effective algae coagulation (e.g., up to 81% algae removal efficiency) can be achieved via heterogeneous nucleation with CaCO3(S); however, supersaturation ratios between 120 and 200 are required to achieve at least 50% algae removal, depending on ion concentrations. Algae removal was attributed to the adsorption of Ca2+ onto the cell surface, which provides nucleation sites for CaCO3(S) precipitation. Bridging of calcite particles between the algal cells led to rapid aggregation and formation of larger flocs. However, at higher supersaturation conditions, algae removal was diminished due to the dominance of homogeneous nucleation of CaCO3(S). The removal of algae in the presence of Ca2+ and Mg2+ required higher supersaturation values; however, the shift from heteronucleation to homonucleation with increasing supersaturation was still evident. The results suggest that water chemistry, pH, ionic strength, alkalinity, and Ca2+ concentration can be optimized for algae removal via coagulation and sedimentation.
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Affiliation(s)
- Jin Yong Choi
- Department of Civil, Architectural and Environmental Engineering , The University of Texas at Austin , Austin , Texas 78712 , United States
| | - Kerry A Kinney
- Department of Civil, Architectural and Environmental Engineering , The University of Texas at Austin , Austin , Texas 78712 , United States
| | - Lynn E Katz
- Department of Civil, Architectural and Environmental Engineering , The University of Texas at Austin , Austin , Texas 78712 , United States
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24
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Blaney L, Lawler DF, Katz LE. Transformation kinetics of cyclophosphamide and ifosfamide by ozone and hydroxyl radicals using continuous oxidant addition reactors. J Hazard Mater 2019; 364:752-761. [PMID: 30428451 DOI: 10.1016/j.jhazmat.2018.09.075] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Revised: 09/21/2018] [Accepted: 09/27/2018] [Indexed: 06/09/2023]
Abstract
The detection of pharmaceuticals in water and wastewater has triggered human and ecological health concerns. As highly toxic compounds, chemotherapy agents (CAs), such as the cyclophosphamide (CYP) and ifosfamide (IFO) structural isomers, represent a unique threat. This research elucidated the fate of CYP and IFO during ozonation and advanced oxidation by hydroxyl radicals (HO•). Novel semi-batch reactors were used to determine the second-order rate constants for CYP and IFO with O3 and HO•. These reactors provided independent control of the oxidant exposure through continuous and constant aqueous ozone and peroxone (O3-H2O2) addition. The rate constants for transformation of CYP and IFO by ozone were 2.58 ± 0.40 M-1s-1 and 6.95 ± 0.21 M-1s-1, respectively, indicating that ozone alone is not suitable for treating CAs. Transformation of CYP and IFO by hydroxyl radicals was fast, with rate constants of 2.69(±0.17)×109 M-1s-1 and 2.73(±0.16)×109 M-1s-1, respectively. The major transformation products formed by O3 and HO attack consisted of the 4-hydroxy-, 4-keto-, dechloroethyl-, and imino- derivatives of CYP and IFO. Low yields of the active metabolites of the CAs, namely phosphoramide mustard and isophosphoramide mustard, were detected. These findings suggest that treated water may retain the ability to alkylate DNA and confer toxicity.
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Affiliation(s)
- Lee Blaney
- University of Maryland Baltimore County, Department of Chemical, Biochemical, and Environmental Engineering, 1000 Hilltop Circle, Engineering 314, Baltimore, MD, 21250-0002, USA.
| | - Desmond F Lawler
- University of Texas at Austin, Department of Civil, Architectural and Environmental Engineering, Environmental and Water Resources Engineering Program, 301 East Dean Keeton Street, Stop C1786, Austin, TX, 78712-1173, USA
| | - Lynn E Katz
- University of Texas at Austin, Department of Civil, Architectural and Environmental Engineering, Environmental and Water Resources Engineering Program, 301 East Dean Keeton Street, Stop C1786, Austin, TX, 78712-1173, USA
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25
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Wahman DG, Speitel GE, Katz LE. Bromamine Decomposition Revisited: A Holistic Approach for Analyzing Acid and Base Catalysis Kinetics. Environ Sci Technol 2017; 51:13205-13215. [PMID: 29072449 PMCID: PMC6058976 DOI: 10.1021/acs.est.7b02661] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Chloramine chemistry is complex, with a variety of reactions occurring in series and parallel and many that are acid or base catalyzed, resulting in numerous rate constants. Bromide presence increases system complexity even further with possible bromamine and bromochloramine formation. Therefore, techniques for parameter estimation must address this complexity through thoughtful experimental design and robust data analysis approaches. The current research outlines a rational basis for constrained data fitting using Brønsted theory, application of the microscopic reversibility principle to reversible acid or base catalyzed reactions, and characterization of the relative significance of parallel reactions using fictive product tracking. This holistic approach was used on a comprehensive and well-documented data set for bromamine decomposition, allowing new interpretations of existing data by revealing that a previously published reaction scheme was not robust; it was not able to describe monobromamine or dibromamine decay outside of the conditions for which it was calibrated. The current research's simplified model (3 reactions, 17 constants) represented the experimental data better than the previously published model (4 reactions, 28 constants). A final model evaluation was conducted based on representative drinking water conditions to determine a minimal model (3 reactions, 8 constants) applicable for drinking water conditions.
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Affiliation(s)
- David G. Wahman
- United States Environmental Protection Agency, Office of Research and Development, Cincinnati, OH 45268
| | - Gerald E. Speitel
- University of Texas at Austin, Department of Civil, Architectural and Environmental Engineering, Austin, TX 78712
| | - Lynn E. Katz
- University of Texas at Austin, Department of Civil, Architectural and Environmental Engineering, Austin, TX 78712
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26
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Saleh NB, Milliron DJ, Aich N, Katz LE, Liljestrand HM, Kirisits MJ. Importance of doping, dopant distribution, and defects on electronic band structure alteration of metal oxide nanoparticles: Implications for reactive oxygen species. Sci Total Environ 2016; 568:926-932. [PMID: 27350094 DOI: 10.1016/j.scitotenv.2016.06.145] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 06/18/2016] [Accepted: 06/18/2016] [Indexed: 05/10/2023]
Abstract
Metal oxide nanoparticles (MONPs) are considered to have the potency to generate reactive oxygen species (ROS), one of the key mechanisms underlying nanotoxicity. However, the nanotoxicology literature demonstrates a lack of consensus on the dominant toxicity mechanism(s) for a particular MONP. Moreover, recent literature has studied the correlation between band structure of pristine MONPs to their ability to introduce ROS and thus has downplayed the ROS-mediated toxicological relevance of a number of such materials. On the other hand, material science can control the band structure of these materials to engineer their electronic and optical properties and thereby is constantly modulating the pristine electronic structure. Since band structure is the fundamental material property that controls ROS-producing ability, band tuning via introduction of dopants and defects needs careful consideration in toxicity assessments. This commentary critically evaluates the existing material science and nanotoxicity literature and identifies the gap in our understanding of the role of important crystal structure features (i.e., dopants and defects) on MONPs' electronic structure alteration as well as their ROS-generation capability. Furthermore, this commentary provides suggestions on characterization techniques to evaluate dopants and defects on the crystal structure and identifies research needs for advanced theoretical predictions of their electronic band structures and ROS-generation abilities. Correlation of electronic band structure and ROS will not only aid in better mechanistic assessment of nanotoxicity but will be impactful in designing and developing ROS-based applications ranging from water disinfection to next-generation antibiotics and even cancer therapeutics.
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Affiliation(s)
- Navid B Saleh
- Department of Civil, Architectural, and Environmental Engineering, University of Texas, Austin, TX 78712, United States.
| | - Delia J Milliron
- McKetta Department of Chemical Engineering, University of Texas, Austin, TX 78712, United States
| | - Nirupam Aich
- Department of Civil, Structural and Environmental Engineering, University at Buffalo, The State University of New York, Buffalo, NY, 14260, United States
| | - Lynn E Katz
- Department of Civil, Architectural, and Environmental Engineering, University of Texas, Austin, TX 78712, United States
| | - Howard M Liljestrand
- Department of Civil, Architectural, and Environmental Engineering, University of Texas, Austin, TX 78712, United States
| | - Mary Jo Kirisits
- Department of Civil, Architectural, and Environmental Engineering, University of Texas, Austin, TX 78712, United States
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27
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Ha Y, Wang X, Liljestrand HM, Maynard JA, Katz LE. Bioavailability of Fullerene under Environmentally Relevant Conditions: Effects of Humic Acid and Fetal Bovine Serum on Accumulation in Lipid Bilayers and Cellular Uptake. Environ Sci Technol 2016; 50:6717-6727. [PMID: 26943027 DOI: 10.1021/acs.est.5b04964] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Carbon fullerene (C60) has emerged at the forefront of nanoscale research and application due to its unique properties. As the production of this nanoparticle rapidly increases, it can be released into natural aquatic environments and can accumulate in biological systems. This research examined the effects of humic acid and fetal bovine serum (FBS), which are ubiquitous in aquatic environments and representative of blood plasma in living organisms, respectively, on bioavailability of fullerene. Bioavailability was investigated using in vitro methods for lipid membrane accumulation and cellular uptake studies. Humic acid and FBS significantly changed the characteristics of fullerene including its particle size and surface charge. The effects of humic acid on lipid accumulation of fullerene depended on the lipid head charge. FBS also significantly decreased the lipid accumulation when positively charged and zwitterionic head groups were present on the lipids, possibly due to the higher steric repulsion of the protein coated nanoparticles. In addition, both humic acid and FBS protein effectively lowered the amounts of fullerene taken up by Caco-2 cells, which are derived from a human colorectal adenocarcinoma and have similar functions to the small intestinal epithelium. Results of this study suggest that surface modification of fullerene by environmentally relevant matrices can significantly affect the biological transport, as well as the possible toxicity of this nanomaterial.
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Affiliation(s)
- Yeonjeong Ha
- Department of Civil, Architectural and Environmental Engineering, The University of Texas at Austin , Austin, Texas 78712, United States
| | - Xianzhe Wang
- Department of Biochemistry, The University of Texas at Austin , Austin, Texas 78712, United States
| | - Howard M Liljestrand
- Department of Civil, Architectural and Environmental Engineering, The University of Texas at Austin , Austin, Texas 78712, United States
| | - Jennifer A Maynard
- Department of Chemical Engineering, The University of Texas at Austin , Austin, Texas 78712, United States
| | - Lynn E Katz
- Department of Civil, Architectural and Environmental Engineering, The University of Texas at Austin , Austin, Texas 78712, United States
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Park CM, Katz LE, Liljestrand HM. Mercury speciation during in situ thermal desorption in soil. J Hazard Mater 2015; 300:624-632. [PMID: 26275352 DOI: 10.1016/j.jhazmat.2015.07.076] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Revised: 07/09/2015] [Accepted: 07/29/2015] [Indexed: 05/08/2023]
Abstract
Metallic mercury (Hg(0)) and its compounds are highly mobile and toxic environmental pollutants at trace level. In situ thermal desorption (ISTD) is one of the soil remediation processes applying heat and vacuum simultaneously. Knowledge of thermodynamic mercury speciation is imperative to understand the fate and transport of mercury during thermal remediation and operate the treatment processes in a cost-effective manner. Hence, speciation model for inorganic mercury was developed over a range of environmental conditions to identify distribution of dissolved mercury species and potential transformations of mercury at near source environment. Simulation of phase transitions for metallic mercury, mercury(II) chloride and mercury sulfide with temperature increase showed that complete vaporization of metallic mercury and mercury(II) chloride were achieved below the boiling point of water. The effect of soil compositions on mercury removal was also evaluated to better understand thermal remediation process. Higher vapor pressures expected both from soil pore water and inorganic carbonate minerals in soil as well as creation of permeability were significant for complete vaporization and removal of mercury.
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Affiliation(s)
- Chang Min Park
- Department of Civil, Architectural and Environmental Engineering, The University of Texas at Austin, 301 E Dean Keeton Street Stop C1786, Austin, TX 78712-1173, USA.
| | - Lynn E Katz
- Department of Civil, Architectural and Environmental Engineering, The University of Texas at Austin, 301 E Dean Keeton Street Stop C1786, Austin, TX 78712-1173, USA
| | - Howard M Liljestrand
- Department of Civil, Architectural and Environmental Engineering, The University of Texas at Austin, 301 E Dean Keeton Street Stop C1786, Austin, TX 78712-1173, USA
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Ha Y, Katz LE, Liljestrand HM. Distribution of Fullerene Nanoparticles between Water and Solid Supported Lipid Membranes: Thermodynamics and Effects of Membrane Composition on Distribution. Environ Sci Technol 2015; 49:14546-53. [PMID: 26569041 DOI: 10.1021/acs.est.5b03339] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The distribution coefficient (Klipw) of fullerene between solid supported lipid membranes (SSLMs) and water was examined using different lipid membrane compositions. Klipw of fullerene was significantly higher with a cationic lipid membrane compared to that with a zwitterionic or anionic lipid membrane, potentially due to the strong interactions between negative fullerene dispersions and positive lipid head groups. The higher Klipw for fullerene distribution to ternary lipid mixture membranes was attributed to an increase in the interfacial surface area of the lipid membrane resulting from phase separation. These results imply that lipid composition can be a critical factor that affects bioconcentration of fullerene. Distribution of fullerene into zwitterionic unsaturated lipid membranes was dominated by the entropy contribution (ΔS) and the process was endothermic (ΔH > 0). This result contrasts the partitioning thermodynamics of highly and moderately hydrophobic chemicals indicating that the lipid-water distribution mechanism of fullerene may be different from that of molecular level chemicals. Potential mechanisms for the distribution of fullerene that may explain these differences include adsorption on the lipid membrane surfaces and partitioning into the center of lipid membranes (i.e., absorption).
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Affiliation(s)
- Yeonjeong Ha
- Department of Civil, Architectural and Environmental Engineering, The University of Texas at Austin , Austin, Texas 78712, United States
| | - Lynn E Katz
- Department of Civil, Architectural and Environmental Engineering, The University of Texas at Austin , Austin, Texas 78712, United States
| | - Howard M Liljestrand
- Department of Civil, Architectural and Environmental Engineering, The University of Texas at Austin , Austin, Texas 78712, United States
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Ortega HG, Liu MC, Pavord ID, Brusselle GG, FitzGerald JM, Chetta A, Humbert M, Katz LE, Keene ON, Yancey SW, Chanez P. Mepolizumab treatment in patients with severe eosinophilic asthma. N Engl J Med 2014; 371:1198-207. [PMID: 25199059 DOI: 10.1056/nejmoa1403290] [Citation(s) in RCA: 1489] [Impact Index Per Article: 148.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND Some patients with severe asthma have frequent exacerbations associated with persistent eosinophilic inflammation despite continuous treatment with high-dose inhaled glucocorticoids with or without oral glucocorticoids. METHODS In this randomized, double-blind, double-dummy study, we assigned 576 patients with recurrent asthma exacerbations and evidence of eosinophilic inflammation despite high doses of inhaled glucocorticoids to one of three study groups. Patients were assigned to receive mepolizumab, a humanized monoclonal antibody against interleukin-5, which was administered as either a 75-mg intravenous dose or a 100-mg subcutaneous dose, or placebo every 4 weeks for 32 weeks. The primary outcome was the rate of exacerbations. Other outcomes included the forced expiratory volume in 1 second (FEV1) and scores on the St. George's Respiratory Questionnaire (SGRQ) and the 5-item Asthma Control Questionnaire (ACQ-5). Safety was also assessed. RESULTS The rate of exacerbations was reduced by 47% (95% confidence interval [CI], 29 to 61) among patients receiving intravenous mepolizumab and by 53% (95% CI, 37 to 65) among those receiving subcutaneous mepolizumab, as compared with those receiving placebo (P<0.001 for both comparisons). Exacerbations necessitating an emergency department visit or hospitalization were reduced by 32% in the group receiving intravenous mepolizumab and by 61% in the group receiving subcutaneous mepolizumab. At week 32, the mean increase from baseline in FEV1 was 100 ml greater in patients receiving intravenous mepolizumab than in those receiving placebo (P=0.02) and 98 ml greater in patients receiving subcutaneous mepolizumab than in those receiving placebo (P=0.03). The improvement from baseline in the SGRQ score was 6.4 points and 7.0 points greater in the intravenous and subcutaneous mepolizumab groups, respectively, than in the placebo group (minimal clinically important change, 4 points), and the improvement in the ACQ-5 score was 0.42 points and 0.44 points greater in the two mepolizumab groups, respectively, than in the placebo group (minimal clinically important change, 0.5 points) (P<0.001 for all comparisons). The safety profile of mepolizumab was similar to that of placebo. CONCLUSIONS Mepolizumab administered either intravenously or subcutaneously significantly reduced asthma exacerbations and was associated with improvements in markers of asthma control. (Funded by GlaxoSmithKline; MENSA ClinicalTrials.gov number, NCT01691521.).
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Affiliation(s)
- Hector G Ortega
- From the Respiratory Therapeutic Area Unit, GlaxoSmithKline, Research Triangle Park, NC (H.G.O., L.E.K., S.W.Y.); Johns Hopkins Asthma and Allergy Center, Baltimore (M.C.L.); Respiratory Medicine Unit, Nuffield Department of Medicine, University of Oxford, Oxford (I.D.P.), and Clinical Statistics, GlaxoSmithKline, Stockley Park, Middlesex (O.N.K.) - both in the United Kingdom; the Department of Respiratory Medicine, Ghent University Hospital, Ghent, Belgium (G.G.B.); the Lung Centre, Institute for Heart and Lung Health, Vancouver, BC, Canada (J.M.F.); the Department of Clinical and Experimental Medicine, University of Parma, Parma, Italy (A.C.); and Assistance Publique-Hôpitaux de Paris, Département Hospitalo-Universitaire Thorax Innovation, Service de Pneumologie, Hôpital Bicêtre, Université Paris-Sud, and INSERM Unité Mixte de Recherche 999, Le Kremlin-Bicêtre (M.H.), and Unités Mixtes de Recherche INSERM Unité 1067 Centre Nationale de la Recherche Scientifique 7733, Aix-Marseille Université, Department of Respiratory Diseases and Clinical Investigation Center, Assistance Publique-Hôpitaux de Marseille, Hôpital Nord, Marseille (P.C.) - both in France
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Carter EM, Jackson MC, Katz LE, Speitel GE. A coupled sensor-spectrophotometric device for continuous measurement of formaldehyde in indoor environments. J Expo Sci Environ Epidemiol 2014; 24:305-310. [PMID: 24084757 DOI: 10.1038/jes.2013.61] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 07/31/2013] [Indexed: 06/02/2023]
Abstract
Despite long-standing awareness of adverse health effects associated with chronic human exposure to formaldehyde, this hazardous air pollutant remains a challenge to measure in indoor environments. Traditional analytical techniques evaluate formaldehyde concentrations over several hours to several days in a single location in a residence, making it difficult to characterize daily temporal and spatial variation in human exposure to formaldehyde. There is a need for portable, easy-to-use devices that are specific and sensitive to gas-phase formaldehyde over short sampling periods so that dynamic processes governing formaldehyde fate, transport, and potential remediation in indoor environments may be studied more effectively. A recently developed device couples a chemical sensor element with spectrophotometric analysis for detection and quantification of part per billion (ppbv) gas-phase formaldehyde concentrations. This study established the ability of the coupled sensor-spectrophotometric device (CSSD) to report formaldehyde concentrations accurately and continuously on a 30-min sampling cycle at low ppbv concentrations previously untested for this device in a laboratory setting. Determination of the method detection limit (MDL), based on 40 samples each at test concentrations of 5 and 10 ppbv, was found to be 1.9 and 2.0 ppbv, respectively. Performance of the CSSD was compared with the dinitrophenylhydrazine (DNPH) derivatization method for formaldehyde concentrations ranging from 5-50 ppbv, and a linear relationship with a coefficient of determination of 0.983 was found between these two analytical techniques. The CSSD was also used to monitor indoor formaldehyde concentrations in two manufactured homes. During this time, formaldehyde concentrations varied from below detection limit to 65 ppbv and were above the US National Institute for Occupational Safety and Health (NIOSH) recommended exposure limit (REL) of 16 ppbv, which is also the exposure limit value now adopted by the US Federal Emergency Management Agency (FEMA) to procure manufactured housing, 80% and 100% of the time, respectively.
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Affiliation(s)
- Ellison M Carter
- Department of Civil, Architectural, and Environmental Engineering, University of Texas at Austin, Cockrell School of Engineering, 1 University Station C1786, Austin, Texas 78712-1173, USA
| | - Mark C Jackson
- Department of Civil, Architectural, and Environmental Engineering, University of Texas at Austin, Cockrell School of Engineering, 1 University Station C1786, Austin, Texas 78712-1173, USA
| | - Lynn E Katz
- Department of Civil, Architectural, and Environmental Engineering, University of Texas at Austin, Cockrell School of Engineering, 1 University Station C1786, Austin, Texas 78712-1173, USA
| | - Gerald E Speitel
- Department of Civil, Architectural, and Environmental Engineering, University of Texas at Austin, Cockrell School of Engineering, 1 University Station C1786, Austin, Texas 78712-1173, USA
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Mangold JE, Park CM, Liljestrand HM, Katz LE. Surface complexation modeling of Hg(II) adsorption at the goethite/water interface using the Charge Distribution Multi-Site Complexation (CD-MUSIC) model. J Colloid Interface Sci 2014; 418:147-61. [DOI: 10.1016/j.jcis.2013.10.066] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Accepted: 10/31/2013] [Indexed: 10/26/2022]
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Katz LE, Criscenti LJ, Chen CC, Larentzos JP, Liljestrand HM. Temperature effects on alkaline earth metal ions adsorption on gibbsite: Approaches from macroscopic sorption experiments and molecular dynamics simulations. J Colloid Interface Sci 2013; 399:68-76. [DOI: 10.1016/j.jcis.2012.05.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Revised: 05/07/2012] [Accepted: 05/08/2012] [Indexed: 11/15/2022]
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Jubb AM, Verreault D, Posner R, Criscenti LJ, Katz LE, Allen HC. Sulfate adsorption at the buried hematite/solution interface investigated using total internal reflection (TIR)-Raman spectroscopy. J Colloid Interface Sci 2013; 400:140-6. [DOI: 10.1016/j.jcis.2013.02.031] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Revised: 02/14/2013] [Accepted: 02/18/2013] [Indexed: 11/28/2022]
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35
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Ha Y, Liljestrand HM, Katz LE. Effects of lipid composition on partitioning of fullerene between water and lipid membranes. Water Sci Technol 2013; 68:290-295. [PMID: 23863419 DOI: 10.2166/wst.2013.211] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Fullerene partition coefficients (Klipw) between water and solid supported lipid membranes were determined for membranes of various lipid types and composition over a range of temperatures. The log Klipw (L/kg) values for fullerene, which range from 3.1 to 5.3, depend on the lipid type in the lipid membranes. Partition coefficients increased with increasing temperature, increasing acyl chain length of unsaturated lipids. The results indicate that lipid composition is a critical factor for bioconcentration of fullerene.
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Affiliation(s)
- Yeonjeong Ha
- Department of Civil, Architectural and Environmental Engineering, The University of Texas at Austin, 1 University Station C1786, Austin, TX 78712, USA
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London MR, De Long SK, Strahota MD, Katz LE, Speitel GE. Autohydrogenotrophic perchlorate reduction kinetics of a microbial consortium in the presence and absence of nitrate. Water Res 2011; 45:6593-6601. [PMID: 22033308 DOI: 10.1016/j.watres.2011.10.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Revised: 08/04/2011] [Accepted: 10/08/2011] [Indexed: 05/31/2023]
Abstract
This is the first study to model the effects of nitrate on autohydrogenotrophic perchlorate biokinetics. Batch experiments demonstrated that the presence of nitrate significantly inhibited perchlorate degradation by a hydrogen-oxidizing, perchlorate-reducing microbial consortium. However, the consortium was capable of significant perchlorate reduction while the bulk of the nitrate was still present. Results showed that a modified competitive inhibition model successfully predicted autohydrogenotrophic perchlorate degradation in the presence of nitrate (initial concentrations of ∼230 μg ClO(4)(-)/L and 2.2-4.6 mg NO(3)(-)-N/L). The model describes perchlorate degradation as a function of the biomass, perchlorate, hydrogen, and nitrate concentrations, as well as the single-component perchlorate (28 μg/L), hydrogen (2.3 × 10(-6) M (aq)), and nitrate (0.15 mg/L as N) half-saturation coefficients (K(s)) and perchlorate maximum substrate utilization rate (k) (1.8 μg ClO(4)(-)/mg TSS-hr). Single-component parameters were obtained through a series of batch experiments performed under perchlorate-, nitrate-, and hydrogen-limiting conditions with initial concentrations of 80-340 μg ClO(4)(-)/L, 2.7-3.6 mg NO(3)(-)-N/L, and 1%-3% H(2) (g) by volume.
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Affiliation(s)
- Mara R London
- Department of Civil, Architectural and Environmental Engineering, The University of Texas at Austin, 1 University Station C1786, Austin, TX 78712-0273, USA
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Kwon S, Sullivan EJ, Katz LE, Bowman RS, Kinney KA. Laboratory and field evaluation of a pretreatment system for removing organics from produced water. Water Environ Res 2011; 83:843-854. [PMID: 22073732 DOI: 10.2175/106143011x12928814445212] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Co-produced water from the oil and gas industry accounts for a significant waste stream in the United States. This "produced water" is characterized by saline water containing a variety of pollutants, including water soluble and immiscible organics and many inorganic species. To reuse produced water, removal of both the inorganic dissolved solids and organic compounds is necessary. In this research, the effectiveness of a pretreatment system consisting of surfactant modified zeolite (SMZ) adsorption followed by a membrane bioreactor (MBR) was evaluated for simultaneous removal of carboxylates and hazardous substances, such as benzene, toluene, ethylbenzene, and xylenes (BTEX) from saline-produced water. A laboratory-scale MBR, operated at a 9.6-hour hydraulic residence time, degraded 92% of the carboxylates present in synthetic produced water. When BTEX was introduced simultaneously to the MBR system with the carboxylates, the system achieved 80 to 95% removal of BTEX via biodegradation. These results suggest that simultaneous biodegradation of both BTEX and carboxylate constituents found in produced water is possible. A field test conducted at a produced water disposal facility in Farmington, New Mexico confirmed the laboratory-scale results for the MBR and demonstrated enhanced removal of BTEX using a treatment train consisting of SMZ columns followed by the MBR. While most of the BTEX constituents of the produced water adsorbed onto the SMZ adsorption system, approximately 95% of the BTEX that penetrated the SMZ and entered the MBR was biodegraded in the MBR. Removal rates of acetate (influent concentrations of 120 to 170 mg/L) ranged from 91 to 100%, and total organic carbon (influent concentrations as high as 580 mg/L) ranged from 74 to 92%, respectively. Organic removal in the MBR was accomplished at a low biomass concentration of 1 g/L throughout the field trial. While the transmembrane pressure during the laboratory-scale tests was well-controlled, it rose substantially during the field test, where no pH control was implemented. The results suggest that pretreatment with an SMZ/MBR system can provide substantial removal of organic compounds present in produced water, a necessary first step for many water-reuse applications.
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Carter EM, Katz LE, Speitel GE, Ramirez D. Gas-phase formaldehyde adsorption isotherm studies on activated carbon: correlations of adsorption capacity to surface functional group density. Environ Sci Technol 2011; 45:6498-6503. [PMID: 21736331 DOI: 10.1021/es104286d] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Formaldehyde (HCHO) adsorption isotherms were developed for the first time on three activated carbons representing one activated carbon fiber (ACF) cloth, one all-purpose granular activated carbon (GAC), and one GAC commercially promoted for gas-phase HCHO removal. The three activated carbons were evaluated for HCHO removal in the low-ppm(v) range and for water vapor adsorption from relative pressures of 0.1-0.9 at 26 °C where, according to the IUPAC isotherm classification system, the adsorption isotherms observed exhibited Type V behavior. A Type V adsorption isotherm model recently proposed by Qi and LeVan (Q-L) was selected to model the observed adsorption behavior because it reduces to a finite, nonzero limit at low partial pressures and it describes the entire range of adsorption considered in this study. The Q-L model was applied to a polar organic adsorbate to fit HCHO adsorption isotherms for the three activated carbons. The physical and chemical characteristics of the activated carbon surfaces were characterized using nitrogen adsorption isotherms, X-ray photoelectron spectroscopy (XPS), and Boehm titrations. At low concentrations, HCHO adsorption capacity was most strongly related to the density of basic surface functional groups (SFGs), while water vapor adsorption was most strongly influenced by the density of acidic SFGs.
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Affiliation(s)
- Ellison M Carter
- Department of Civil, Architectural, and Environmental Engineering, University of Texas at Austin, Cockrell School of Engineering, Austin, Texas 78712-0284, United States
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Wahman DG, Katz LE, Speitel GE. Performance and biofilm activity of nitrifying biofilters removing trihalomethanes. Water Res 2011; 45:1669-1680. [PMID: 21195446 DOI: 10.1016/j.watres.2010.12.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2010] [Revised: 12/07/2010] [Accepted: 12/08/2010] [Indexed: 05/30/2023]
Abstract
Nitrifying biofilters seeded with three different mixed-culture sources removed trichloromethane (TCM) and dibromochloromethane (DBCM) with removals reaching 18% for TCM and 75% for DBCM. In addition, resuspended biofilm removed TCM, bromodichloromethane (BDCM), DBCM, and tribromomethane (TBM) in backwash batch kinetic tests, demonstrating that the biofilters contained organisms capable of biotransforming the four regulated trihalomethanes (THMs) commonly found in treated drinking water. Upon the initial and subsequent increased TCM addition, total ammonia nitrogen (TOTNH(3)) removal decreased and then reestablished, indicating an adjustment by the biofilm bacteria. In addition, changes in DBCM removal indicated a change in activity related to DBCM. The backwash batch kinetic tests provided a useful tool to evaluate the biofilm's bacteria. Based on these experiments, the biofilters contained bacteria with similar THM removal kinetics to those seen in previous batch kinetic experiments. Overall, performance or selection does not seem based specifically on nutrients, source water, or source cultures and most likely results from THM product toxicity, and the use of GAC media appeared to offer benefits over anthracite for biofilter stability and long-term performance, although the reasons for this advantage are not apparent based on research to date.
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Affiliation(s)
- David G Wahman
- United States Environmental Protection Agency, Office of Research and Development, 26 W. Martin Luther King Dr., Cincinnati, OH 45268, USA.
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Abstract
In-situ capping has shown promise as a management strategy for contaminated aquatic sediments, however, little is known about how mercury methylation in underlying sediments will be affected. Changes to the location and extent of sulfate reduction and other biological processes were studied in estuarine sediment using laboratory microcosms. Observations in a model sediment showed increases of in situ total methylmercury concomitant with an upward extension of anaerobic bacterial activity beneath a sediment cap and under anoxic conditions. Increased methylmercury (up to 50%) was observed beneath a sediment cap in a region 2-3 cm higher than in an uncapped sediment. A 1-dimensional, unsteady, reaction transport model was used to simulate the transient response to mercury-related biogeochemical processes. The location, magnitude, and expected duration of the increased methylmercury was such that a significant impact on near cap-water interface methylmercury was not expected for the sediments studied. Explicit consideration of the biogeochemical effects of capping on mercury contaminated sediment, however, may be necessary for very thin or unstable capping layers where the physical sequestration provided by a cap may be compromised.
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Affiliation(s)
- Nathan W Johnson
- Department of Civil Architectural and Environmental Engineering, University of Texas at Austin, USA
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Russell CG, Lawler DF, Speitel GE, Katz LE. Effect of softening precipitate composition and surface characteristics on natural organic matter adsorption. Environ Sci Technol 2009; 43:7837-7842. [PMID: 19921902 DOI: 10.1021/es900991n] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Natural organic matter (NOM) removal during water softening is thought to occur through adsorption onto or coprecipitation with calcium and magnesium solids. However, details of precipitate composition and surface chemistry and subsequent interactions with NOM are relatively unknown. In this study, zeta potentiometry analyses of precipitates formed from inorganic solutions under varying conditions (e.g., Ca-only, Mg-only, Ca + Mg, increasing lime or NaOH dose) indicated that both CaCO3 and Mg(OH)2 were positively charged at higher lime (Ca(OH)2) and NaOH doses (associated with pH values above 11.5), potentially yielding a greater affinity for adsorbing negatively charged organic molecules. Environmental scanning electron microscopy (ESEM) images of CaCO3 solids illustrated the rhombohedral shape characteristic of calcite. In the presence of increasing concentrations of magnesium, the CaCO3 rhombs shifted to more elongated crystals. The CaCO3 solids also exhibited increasingly positive surface charge from Mg incorporation into the crystal lattice, potentially creating more favorable conditions for adsorption of organic matter. NOM adsorption experiments using humic substances extracted from Lake Austin and Missouri River water elucidated the role of surface charge and surface area on adsorption.
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Affiliation(s)
- Caroline G Russell
- The University of Texas at Austin, Department of Civil, Architectural, and Environmental Engineering, Austin, Texas 78712, USA.
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Kwon JH, Katz LE, Liljestrand HM. Modeling binding equilibrium in a competitive estrogen receptor binding assay. Chemosphere 2007; 69:1025-31. [PMID: 17559906 DOI: 10.1016/j.chemosphere.2007.04.047] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2006] [Revised: 04/11/2007] [Accepted: 04/16/2007] [Indexed: 05/15/2023]
Abstract
Although the free concentration is more significant in the environmental chemistry and toxicology of receptor-mediated toxicants, few studies have been conducted to use it as a dose-metric. The relative binding affinity of three model endocrine disrupting compounds, diethylstilbestrol (DES), ethynylestradiol (EE2), and bisphenol A (BPA), were evaluated using a competitive ELISA with human estrogen receptor alpha. After measuring the available receptors and the dissociation constant for 17beta-estradiol, binding inhibition curves using the free concentration as the dose-metric were obtained by assuming species equilibrium in the ELISA system and compared with apparent inhibition curves generated using the nominal concentration as the dose-metric. Because ligand binding to estrogen receptors may reduce its free concentration in the assay system, the differences between the two curves for free and nominal concentrations are more significant for more strongly binding ligands. The ratio of a compound's nominal concentration causing 50% inhibition (IC50) to the IC50 of DES, the positive control, was strongly affected by specific assay conditions, while that estimated by modeling free concentration is independent of receptor concentration, indicating that the free concentration is a better dose-metric for a competitive binding assay.
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Affiliation(s)
- Jung-Hwan Kwon
- Department of Civil, Architectural and Environmental Engineering, The University of Texas at Austin, 1 University Station C1786, Austin, TX 78712-0273, USA
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Kwon JH, Liljestrand HM, Katz LE, Yamamoto H. Partitioning thermodynamics of selected endocrine disruptors between water and synthetic membrane vesicles: effects of membrane compositions. Environ Sci Technol 2007; 41:4011-8. [PMID: 17612183 DOI: 10.1021/es0618200] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The thermodynamics of partitioning of selected endocrine disruptors between water and synthetic membrane vesicles were investigated. For most of the chemicals investigated, partitioning is dominated by the enthalpy change for unsaturated lipid membrane vesicles and by the entropy contribution for saturated lipid membrane vesicles. The contribution of the entropy terms in determining the free-energy change becomes more important compared with the enthalpy terms with increased branching of p-substituted phenols. These results suggest that the thermal energy required for and the entropy gain associated with the creation of the cavity in the lipid bilayer is of critical importance in differentiating the process from 1-octanol/water partitioning. In addition, partitioning thermodynamics are significantly influenced by cholesterol content in the lipid membranes. Results of the present study and those in the literature suggest that partitioning processes significantly depend on the physical state of the lipid membranes and log K(ow)-based quantitative structure-activity relationships should be carefully applied for predicting bioconcentration by considering lipid compositions.
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Affiliation(s)
- Jung-Hwan Kwon
- Department of Civil, Architectural and Environmental Engineering, The University of Texas at Austin, 1 University Station C1786, Austin, Texas 78712-0273, USA
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Wahman DG, Katz LE, Speitel GE. Modeling of trihalomethane cometabolism in nitrifying biofilters. Water Res 2007; 41:449-57. [PMID: 17129595 DOI: 10.1016/j.watres.2006.10.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2005] [Revised: 08/09/2006] [Accepted: 10/11/2006] [Indexed: 05/12/2023]
Abstract
The computer program AQUASIM was used to model biofilter experiments seeded with Lake Austin, Texas mixed-culture nitrifiers. These biofilters degraded four trihalomethanes (THMs) (trichloromethane (TCM) or chloroform, bromodichloromethane (BDCM), dibromochloromethane (DBCM), tribromomethane (TBM) or bromoform) commonly found in treated drinking water. Apparent steady-state data from the biofilter experiments and supporting batch experiments were used to estimate kinetic parameters for TCM, DBCM and ammonia degradation. Subsequently, the model was verified against other experimental biofilter data. To allow for full-scale simulations, BDCM and TBM rate constants were estimated using data from batch kinetic studies. Finally, the model was used to simulate full-scale filter performance under different filter surface loading rates and THM speciation seen in practice. Overall, total THM removals ranged from 16% to 54% in these simulations with influent total THM concentrations of 75-82microg/L, which illustrates the potential of THM cometabolism to have a significant impact on treated water quality.
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Affiliation(s)
- David G Wahman
- Department of Civil, Architectural and Environmental Engineering, University of Texas at Austin, Austin, TX 78712, USA
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Kwon JH, Katz LE, Liljestrand HM. Use of a parallel artificial membrane system to evaluate passive absorption and elimination in small fish. Environ Toxicol Chem 2006; 25:3083-92. [PMID: 17220075 DOI: 10.1897/06-013r.1] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
A parallel artificial lipid membrane system was developed to mimic passive mass transfer of hydrophobic organic chemicals in fish. In this physical model system, a membrane filter-supported lipid bilayer separates two aqueous phases that represent the external and internal aqueous environments of fish. To predict bioconcentration kinetics in small fish with this system, literature absorption and elimination rates were analyzed with an allometric diffusion model to quantify the mass transfer resistances in the aqueous and lipid phases of fish. The effect of the aqueous phase mass transfer resistance was controlled by adjusting stirring intensity to mimic bioconcentration rates in small fish. Twenty-three simple aromatic hydrocarbons were chosen as model compounds for purposes of evaluation. For most of the selected chemicals, literature absorption/elimination rates fall into the range predicted from measured membrane permeabilities and elimination rates of the selected chemicals determined by the diffusion model system.
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Affiliation(s)
- Jung-Hwan Kwon
- Department of Civil, Architectural and Environmental Engineering, The University of Texas at Austin, I University Station C1786, Austin, Texas 78712-0273, USA
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Wahman DG, Henry AE, Katz LE, Speitel GE. Cometabolism of trihalomethanes by mixed culture nitrifiers. Water Res 2006; 40:3349-58. [PMID: 16970971 DOI: 10.1016/j.watres.2006.07.033] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2005] [Revised: 06/28/2006] [Accepted: 07/28/2006] [Indexed: 05/11/2023]
Abstract
Three mixed-culture nitrifier sources degraded low concentrations (25-450 microg/L) of four trihalomethanes (THMs) (trichloromethane (TCM) or chloroform, bromodichloromethane (BDCM), dibromochloromethane (DBCM), tribromomethane (TBM) or bromoform) commonly found in treated drinking water. Individual THM rate constants (k1THM) increased with increasing THM bromine-substitution with TBM>DBCM>BDCM>TCM and were comparable to previous studies with the pure culture nitrifier, Nitrosomonas europaea. A decrease in temperature resulted in a decrease in both ammonia and THM degradation rates with ammonia rates affected to a greater extent than THM degradation rates. The significant effect of temperature indicates that seasonal variations in water temperature should be a consideration for technology implementation. Product toxicity, measured by transformation capacity (T(c)), was similar to that observed with N. europaea. Because both rate constants and product toxicities increase with increasing THM bromine-substitution, a water's THM speciation is an important consideration for process implementation during drinking water treatment. Even though a given water is kinetically favored, the resulting THM product toxicity may not allow stable treatment process performance.
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Affiliation(s)
- David G Wahman
- Department of Civil, Architectural and Environmental Engineering, University of Texas at Austin, 1 University Station C1700, Austin, TX 78712-0273, USA
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Wiesner AD, Katz LE, Chen CC. The impact of ionic strength and background electrolyte on pH measurements in metal ion adsorption experiments. J Colloid Interface Sci 2006; 301:329-32. [PMID: 16765363 DOI: 10.1016/j.jcis.2006.05.011] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2006] [Revised: 05/02/2006] [Accepted: 05/03/2006] [Indexed: 11/22/2022]
Abstract
Our understanding of metal ion adsorption to clay minerals has progressed significantly over the past several decades, and theories have been promulgated to describe and predict the impacts of pH, ionic strength, and background solution composition on the extent of adsorption. Studies evaluating the effects of ionic strength on adsorption typically employ a broad range of background electrolyte concentrations. Measurement of pH in these systems can be inaccurate when pH values are measured with liquid junction pH probes calibrated with standard buffers due to changes in the liquid junction potential between standard, low ionic strength (0.05 M) buffers and high ionic strength solutions (>0.1 M). The objective of this research is to determine the extent of the error in pH values measured at high ionic strength, and to develop an approach for accurately measuring pH over a range of ionic strengths using a combined pH electrode. To achieve this objective, the adsorption of cobalt (10(-5) M) onto gibbsite (10 g/L) from various electrolyte solutions (0.01-1 M) was studied. The pH measurements were determined from calibrations with standard buffers and ionic strength corrected buffer calibrations. The results show a significant effect of the aqueous solution background electrolyte anion and ionic strength on pH measurement. The 0.5 and 1 M ionic strength metal ion adsorption edges shifted to lower pH with increasing ionic strength when pH was calibrated with standard buffers whereas no shift in the adsorption edges was observed when calibrated with ionic strength corrected buffers. Therefore, to obtain an accurate pH measurement, pH calibration should contain the same electrolyte and ionic strength as the samples.
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Affiliation(s)
- Andrew D Wiesner
- Department of Civil, Architectural and Environmental Engineering, College of Engineering, The University of Texas at Austin, 1 University Station C1700, Austin, TX 78712, USA
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Kwon JH, Liljestrand HM, Katz LE. Partitioning of moderately hydrophobic endocrine disruptors between water and synthetic membrane vesicles. Environ Toxicol Chem 2006; 25:1984-92. [PMID: 16916015 DOI: 10.1897/05-550r.1] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The partition coefficient between water and lipid membrane vesicles (Klipw) has been used as an alternative to the 1-octanol-water partition coefficient (Kow) between water and organic solvent, because it more closely represents actual biological membranes. Despite theoretical differences, log Klipw correlates well with log Kow for conventional nonpolar organic pollutants. In the present study, Klipw values of 11 structurally diverse endocrine-disrupting chemicals (EDCs) were measured for three different types of lipid membrane vesicles from dipalmitoylphosphatidylcholine (DPPC), DPPC/cholesterol, and palmitoyloleoylphosphatidylcholine. Correlation analyses were conducted to evaluate the effects of hydrophobicity, molar liquid volume (MLV), and polar surface area (PSA) for 20 EDCs, including nine from a previous study. Correlations that include MLV and PSA reduce the predicted value of log Klipw, suggesting that lipid membranes are less favorable than 1-octanol for a hydrophobic solute because of the higher molar volume and higher hydrogen-bonding potential. These results suggested that Kow alone has limited potential for estimating Klipw and that additional descriptors are required. In addition, Klipw values vary by as much as two orders of magnitude because of the changes in membrane fluidity and the amount of cholesterol in the lipid bilayer. Therefore, lipid components should be chosen carefully to evaluate the bioconcentration of these compounds.
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Affiliation(s)
- Jung-Hwan Kwon
- Department of Civil, Architectural and Environmental Engineering, University of Texas at Austin, 1 University Station C1786, Austin, Texas 78712-0273, USA
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