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Nakazawa Y, Kosaka K, Asami M, Matsui Y. Maximum desorption of perfluoroalkyl substances adsorbed on granular activated carbon used in full-scale drinking water treatment plants. WATER RESEARCH 2024; 254:121396. [PMID: 38479172 DOI: 10.1016/j.watres.2024.121396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 01/08/2024] [Accepted: 02/27/2024] [Indexed: 04/06/2024]
Abstract
Activated carbon adsorption is an effective method for removing perfluoroalkyl substances (PFAS) from water. However, the observation that higher concentrations of PFAS are observed after treatment than before (i.e., desorption) is an important, unsolved issue. In this study, to elucidate PFAS desorption and its relationship with PFAS properties, we conducted solvent extraction and long-term desorption experiments using granular activated carbon (GAC) that had been loaded with PFAS in two actual drinking water treatment plants. The amount of PFAS extracted from GAC depended on the depth in the GAC filter; longer-chain and hydrophobic PFAS were present in relatively higher amounts in the shallow part compared to the deep part of the GAC filter, whereas shorter-chain and hydrophilic PFAS were present in relatively higher amounts in the deep part compared to the shallow part. This pattern was probably due to a chromatographic effect by which hydrophilic PFAS adsorbed once, subsequently desorbed, and migrated from the shallow part of the GAC filter to the deeper part. The desorption potential of PFAS to water (i.e., the maximum amount of PFAS desorbed to water per unit mass of GAC) was estimated by conducting long-term bottle-point desorption tests and analyzing the relationship between the equilibrium water-phase concentration of PFAS in a bottle containing GAC and the amount of PFAS desorbed to water per unit GAC mass. The desorption ratio (ratio of desorption potential to loading) was the highest for PFAS for which the logarithm of the octanol/water distribution coefficient (Log DOW) ranged from -1 to 1. The implication was that most of those PFAS removed by GAC were likely to return to the water as the external water-phase concentrations dropped. The decrease of the desorption ratio to 20 % as Log DOW increased suggested irreversible adsorption due to hydrophobic affinity.
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Affiliation(s)
- Yoshifumi Nakazawa
- Department of Environmental Health, National Institute of Public Health, 2-3-6 Minami, Wako, Saitama 351-0197, Japan.
| | - Koji Kosaka
- Department of Environmental Health, National Institute of Public Health, 2-3-6 Minami, Wako, Saitama 351-0197, Japan
| | - Mari Asami
- Department of Environmental Health, National Institute of Public Health, 2-3-6 Minami, Wako, Saitama 351-0197, Japan
| | - Yoshihiko Matsui
- Faculty of Engineering, Hokkaido University, N13W8, Sapporo 060-8628, Japan
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The Influence of the Chemical Composition of Natural Waters about the Triclocarban Sorption on Pristine and Irradiated MWCNTs. SEPARATIONS 2023. [DOI: 10.3390/separations10010046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The influence of the chemical composition of natural waters on triclocarban (TCC) sorption on pristine and irradiated multi-walled carbon nanotubes (MWCNTs) at different temperatures was studied. Natural waters have been characterized in terms of the concentrations of cations and anions, pH, and electric conductivity. The sorption process of TCC on MWCNTs is influenced by both the chemical composition of natural waters and the variation of the temperature. The adsorption capacity of TCC on pristine and irradiated MWCNTs in the studied natural waters increased by increasing the temperature. The increase of the concentration of monovalent cations (Na+ and K+) in natural waters determined a significant decrease of the adsorption capacity of TCC on both pristine and irradiated MWCNTs while the increase of the bivalent cations (Ca2+ and Mg2+) determined an easy increase adsorption capacity. Freundlich and Langmuir models were selected to describe the steady adsorption of the TCC on the pristine and irradiated MWCNTs.
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Washburn SJ, Damond J, Sanders JP, Gilmour CC, Ghosh U. Uptake Mechanisms of a Novel, Activated Carbon-Based Equilibrium Passive Sampler for Estimating Porewater Methylmercury. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2022; 41:2052-2064. [PMID: 35698924 PMCID: PMC9420783 DOI: 10.1002/etc.5406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 10/25/2021] [Accepted: 06/10/2022] [Indexed: 06/15/2023]
Abstract
We describe the validation of a novel polymeric equilibrium passive sampler comprised of agarose gel with embedded activated carbon particles (ag+AC), to estimate aqueous monomethylmercury (MeHg) concentrations. Sampler behavior was tested using a combination of idealized media and realistic sediment microcosms. Isotherm bottle experiments with ag+AC polymers were conducted to constrain partitioning to these materials by various environmentally relevant species of MeHg bound to dissolved organic matter (MeHgDOM) across a range of sizes and character. Log of partitioning coefficients for passive samplers (Kps ) ranged from 1.98 ± 0.09 for MeHg bound to Suwannee River humic acid to 3.15 ± 0.05 for MeHg complexed with Upper Mississippi River natural organic matter. Reversible equilibrium exchange of environmentally relevant MeHg species was demonstrated through a series of dual isotope-labeled exchange experiments. Isotopically labeled MeHgDOM species approached equilibrium in the samplers over 14 days, while mass balance was maintained, providing strong evidence that the ag+AC polymer material is capable of equilibrium measurements of environmentally relevant MeHg species within a reasonable deployment time frame. Samplers deployed across the sediment-water interface of sediment microcosms estimated both overlying water and porewater MeHg concentrations within a factor of 2 to 4 of measured values, based on the average measured Kps values for species of MeHg bound to natural organic matter in the isotherm experiments. Taken together, our results indicate that ag+AC polymers, used as equilibrium samplers, can provide accurate MeHg estimations across many site chemistries, with a simple back-calculation based on a standardized Kps. Environ Toxicol Chem 2022;41:2052-2064. © 2022 SETAC.
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Affiliation(s)
- Spencer J. Washburn
- Smithsonian Environmental Research Center, 647 Contees
Wharf Road, Edgewater, Maryland 21037, United States
| | - Jada Damond
- Department of Chemical, Biochemical, and Environmental
Engineering University of Maryland Baltimore County, 5200 Westland Blvd., Baltimore,
Maryland 21250, United States
| | - James P. Sanders
- US Environmental Protection Agency, Office of Pollution
Prevention and Toxics, Washington, DC 20460, United States
| | - Cynthia C. Gilmour
- Smithsonian Environmental Research Center, 647 Contees
Wharf Road, Edgewater, Maryland 21037, United States
| | - Upal Ghosh
- Department of Chemical, Biochemical, and Environmental
Engineering University of Maryland Baltimore County, 5200 Westland Blvd., Baltimore,
Maryland 21250, United States
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Ma X, Wang L, Wang H, Deng J, Song Y, Li Q, Li X, Dietrich AM. Insights into metal-organic frameworks HKUST-1 adsorption performance for natural organic matter removal from aqueous solution. JOURNAL OF HAZARDOUS MATERIALS 2022; 424:126918. [PMID: 34775305 DOI: 10.1016/j.jhazmat.2021.126918] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 08/02/2021] [Accepted: 08/14/2021] [Indexed: 06/13/2023]
Abstract
Natural organic matter (NOM) has rich halogenation reactive sites, therefore acts as the main precursor of disinfection byproducts (DBPs) in the chlorine disinfection process during drinking water treatment. In this research, high-quality metal-organic framework HKUST-1 is rapidly synthesized by a solvothermal method, and we are the first to report adsorption of aqueous humic acid (HA), representing NOM, and its adsorption behavior, influencing factors, and recycling capability. The crystalline HKUST-1 possessed a microporous framework with a high 1385 m2/g specific surface area, and three-dimensional structure as characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM). 99% removal of 5 mg/L HA was observed at pH 5.8, room temperature, and 0.6 g/L HKUST-1. The maximum capacity was 14.42 mg HA/g HKUST-1 at room temperature. The Langmuir adsorption isotherm, quasi-second-order kinetic model, and thermodynamic parameters accurately describe the spontaneous and disorderly endothermic adsorption of HA by HKUST-1. The desorption regeneration process was accomplished by washing HKUST-1 with NaOH and calcination; it showed that HKUST-1 was viable in three regeneration cycles. The mechanism of HA adsorption by HKUST-1 is electrostatic and synergistic interaction between π-π bonding, and hydrogen bonding. HKUST-1 is a potential treatment strategy to remove NOM.
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Affiliation(s)
- Xiaoyan Ma
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou 310023, China
| | - Lei Wang
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou 310023, China
| | - Hong Wang
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou 310023, China
| | - Jing Deng
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou 310023, China
| | - Yali Song
- School of Civil Engineering and Architecture, Zhejiang University of Science and Technology, Hangzhou 310023, China.
| | - Qingsong Li
- Water Resources and Environmental Institute, Xiamen University of Technology, Xiamen 361005, China
| | - Xueyan Li
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, China
| | - Andrea M Dietrich
- Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, Blackburg, VA 24061, USA
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5
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Zhao Z, Sun W, Ray MB. Adsorption isotherms and kinetics for the removal of algal organic matter by granular activated carbon. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 806:150885. [PMID: 34634354 DOI: 10.1016/j.scitotenv.2021.150885] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 09/15/2021] [Accepted: 10/04/2021] [Indexed: 06/13/2023]
Abstract
Seasonal algal blooms in surface water release a significant amount of algal organic matter (AOM), which alters the composition of dissolved organic matter (DOM). AOM affects the drinking water treatment processes and finished water quality. In this study, the relative removal efficiency of AOM and humic acid by granular activated carbon (GAC) adsorption was determined. Batch experiments were conducted to evaluate the adsorption capacity of GAC, which varied from 4.235-31.45 mg/g for AOM originated from different algae. Freundlich isotherm models fitted the adsorption equilibrium data, and the adsorption kinetics data were fitted well using a pseudo-second order kinetic model. The calculated thermodynamics parameters (∆G0, ∆H0 and ∆S0) indicated that GAC adsorption for DOM removal was endothermic and spontaneous in nature.
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Affiliation(s)
- Ziming Zhao
- Luoyang R&D Center of Technology, SINOPEC Engineering (Group) Co., Ltd, Henan 471003, China; Department of Chemical and Biochemical Engineering, University of Western Ontario, London, Ontario N6A 5B9, Canada
| | - Wenjun Sun
- School of Environment, Tsinghua University, Beijing 100084, China.
| | - Madhumita B Ray
- Department of Chemical and Biochemical Engineering, University of Western Ontario, London, Ontario N6A 5B9, Canada.
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Yuan J, Huang Y, Nie Z, Hofmann R. The effect of water temperature on the removal of 2-methylisoborneol and geosmin by preloaded granular activated carbon. WATER RESEARCH 2020; 183:116065. [PMID: 32721706 DOI: 10.1016/j.watres.2020.116065] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 06/09/2020] [Accepted: 06/14/2020] [Indexed: 06/11/2023]
Abstract
Granular activated carbon (GAC) is widely used by drinking water treatment plants in the Great Lakes region to control 2-methylisoborneol (MIB) and geosmin associated with summertime algal blooms. Recently, however, taste and odour events are being detected in the winter, but there is limited information in the literature about the effect of temperature on GAC performance. In this study, batch isotherm experiments were conducted at 4 °C, 10 °C, and 20 °C to evaluate the temperature impact on adsorption thermodynamics. Pilot-scale column tests were then performed at the same temperatures to evaluate the temperature effect on overall removal, including both thermodynamics and kinetics. The pore and surface diffusion model (PSDM) was applied to fit the experimental data of the pilot-scale column tests, which allowed the kinetic parameters to be determined at each temperature. The isotherm results showed that water temperature did not have a significant effect on the equilibrium adsorption capacity (i.e., the thermodynamics) for MIB and geosmin under the conditions tested, but the pilot tests showed an increased removal of MIB and geosmin by 20-30% at 20 °C compared to the lower temperatures. This demonstrates that water temperature has more impact on kinetics than thermodynamics. Numerical simulations showed that the overall external mass transfer coefficient, Kf', had the greatest impact on breakthrough. An exponential equation was proposed to correlate temperature and Kf', and it could be incorporated into a site-specific PSDM to predict the removals of MIB and geosmin in GAC contactors at different temperatures. The model could then be used by a utility, for example, to predict the required increase in empty bed contact time needed to control taste and odour in the winter to the same extent as in the summer.
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Affiliation(s)
- Jie Yuan
- Drinking Water Research Group, Department of Civil & Mineral Engineering, University of Toronto, Ontario, M5S 1A4, Canada.
| | - Yifeng Huang
- Drinking Water Research Group, Department of Civil & Mineral Engineering, University of Toronto, Ontario, M5S 1A4, Canada
| | - Zhijie Nie
- Drinking Water Research Group, Department of Civil & Mineral Engineering, University of Toronto, Ontario, M5S 1A4, Canada
| | - Ronald Hofmann
- Drinking Water Research Group, Department of Civil & Mineral Engineering, University of Toronto, Ontario, M5S 1A4, Canada
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Haddad M, Oie C, Vo Duy S, Sauvé S, Barbeau B. Adsorption of micropollutants present in surface waters onto polymeric resins: Impact of resin type and water matrix on performance. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 660:1449-1458. [PMID: 30743938 DOI: 10.1016/j.scitotenv.2018.12.247] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 12/15/2018] [Accepted: 12/16/2018] [Indexed: 06/09/2023]
Abstract
The occurrence of micropollutants in water resources is raising substantial concerns, worldwide. These pollutants may have adverse impacts on the aquatic ecosystem and human health. Even though activated carbon is commonly used as an adsorbent to remove micropollutants from water, its low removal of hydrophilic components, energy-intensive regeneration procedure and slow adsorption can impair its applicability. Polymeric resins have been suggested as an effective alternative adsorbent due to their high porosity and accessible adsorption sites, significant adsorption concentration and stable chemical properties. In this work, we evaluated the performance of five commercially available polymeric resins (including two ion exchange resins) for the removal of nine selected micropollutants in water. More specifically, we investigated the effect of polymeric resin type and concentration, contact time and water matrix on the removal efficiency of five pharmaceuticals, two pesticides and two endocrine disruptors of high current concern (diclofenac, sulfamethoxazole, fluoxetine, caffeine, carbamazepine, 17-β estradiol, norethindrone, atrazine and desesthylatrazine). Results presented herein indicated that two hydrophobic polymeric resins can effectively adsorb over 80% of the targeted micropollutants within 30 min when the resin concentration was higher than 2.5 mL L-1. The adsorption data were well described with the Freundlich isotherm and the pseudo-second order kinetic model very well described the kinetic process of the selected micropollutants onto the polymeric resins. Moreover, we observed that increasing the synthetic water temperature from 4 to 22 °C led to a marginally higher micropollutant uptake and the presence of natural organic matter had no noted impact on the efficiency of the resins in removing the tested micropollutants when the resin dosage was 5.4 mL L-1. On the basis of these promising results, we conclude that polymeric resins are a promising alternative to activated carbon for micropollutants sorption in drinking water treatment.
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Affiliation(s)
- Maryam Haddad
- NSERC-Industrial Chair on Drinking Water, Polytechnique de Montréal, Canada.
| | - Celso Oie
- NSERC-Industrial Chair on Drinking Water, Polytechnique de Montréal, Canada
| | - Sung Vo Duy
- Department of Chemistry, Université de Montréal, Canada
| | | | - Benoit Barbeau
- NSERC-Industrial Chair on Drinking Water, Polytechnique de Montréal, Canada
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Hou X, Huang X, Ai Z, Zhao J, Zhang L. Ascorbic acid induced atrazine degradation. JOURNAL OF HAZARDOUS MATERIALS 2017; 327:71-78. [PMID: 28043044 DOI: 10.1016/j.jhazmat.2016.12.048] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 11/30/2016] [Accepted: 12/24/2016] [Indexed: 06/06/2023]
Abstract
In this study, we systematically investigated the degradation efficiency and the degradation mechanism of atrazine in the presence of ascorbic acid at different pH values. Although atrazine could be degraded by ascorbic acid in a wide pH range from 4 to 12, its degradation under either acidic (pH≤4) or alkaline (pH≥12) condition was more efficient than under neutral condition (pH=7). This pH dependent atrazine degradation was related to the reactive characteristic of atrazine and the reductive activity of ascorbic acid. The ascorbic acid induced atrazine degradation pathways at different pH were investigated by comparing the atrazine degradation intermediates with liquid chromatography-mass spectrometry, high performance liquid chromatography and ion chromatography. It was found that more products were detected in presence of ascorbic acid at alkaline condition. The appearance of chloride ions confirmed the dechlorination of atrazine by ascorbic acid in the absence of molecular oxygen, while its dechlorination efficiency reached highest at pH 12. These results can shed light on the application of AA for the organic pollutant remediation.
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Affiliation(s)
- Xiaojing Hou
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, PR China
| | - Xiaopeng Huang
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, PR China
| | - Zhihui Ai
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, PR China.
| | - Jincai Zhao
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, PR China
| | - Lizhi Zhang
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, PR China.
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9
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Nam SW, Choi DJ, Kim SK, Her N, Zoh KD. Adsorption characteristics of selected hydrophilic and hydrophobic micropollutants in water using activated carbon. JOURNAL OF HAZARDOUS MATERIALS 2014; 270:144-52. [PMID: 24572271 DOI: 10.1016/j.jhazmat.2014.01.037] [Citation(s) in RCA: 191] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2013] [Revised: 12/14/2013] [Accepted: 01/21/2014] [Indexed: 05/22/2023]
Abstract
In this study, we investigated adsorption characteristics of nine selected micropollutants (six pharmaceuticals, two pesticides, and one endocrine disruptor) in water using an activated carbon. The effects of carbon dosage, contact time, pH, DOM (dissolved organic matter), and temperature on the adsorption removal of micropollutants were examined. Increasing carbon dosage and contact time enhanced the removal of micropollutants. Sorption coefficients of hydrophilic compounds (caffeine, acetaminophen, sulfamethoxazole, and sulfamethazine) fit a linear isotherm and hydrophobic compounds (naproxen, diclofenac, 2, 4-D, triclocarban, and atrazine) fit a Freundlich isotherm. The removal of hydrophobic pollutants and caffeine were independent of pH changes, but acetaminophen, sulfamethazine, and sulfamethoxazole were adsorbed by mainly electrostatic interaction with activated carbon and so were affected by pH. The decrease in adsorption removal in surface water samples was observed and this decrease was more significant for hydrophobic than hydrophilic compounds. The decline in the adsorption capacity in surface water samples is caused by the competitive inhibition of DOM with micropollutants onto activated carbon. Low temperature (5°C) also decreased the adsorption removal of micropollutants, and affected hydrophobic compounds more than hydrophilic compounds. The results obtained in this study can be applied to optimize the adsorption capacities of micropollutants using activated carbon in water treatment process.
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Affiliation(s)
- Seung-Woo Nam
- Department of Environmental Health, School of Public Health, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, Republic of Korea
| | - Dae-Jin Choi
- Department of Environmental Health, School of Public Health, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, Republic of Korea
| | - Seung-Kyu Kim
- Department of Marine Science, College of Natural Science, Incheon National University, Incheon, Republic of Korea
| | - Namguk Her
- Department of Chemistry and Environmental Sciences, Korea Army Academy at Young-Cheon, Young-Cheon, Gyeongbuk, Republic of Korea
| | - Kyung-Duk Zoh
- Department of Environmental Health, School of Public Health, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, Republic of Korea.
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Kovalova L, Knappe DRU, Lehnberg K, Kazner C, Hollender J. Removal of highly polar micropollutants from wastewater by powdered activated carbon. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2013; 20:3607-3615. [PMID: 23299971 DOI: 10.1007/s11356-012-1432-9] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Accepted: 12/12/2012] [Indexed: 06/01/2023]
Abstract
Due to concerns about ecotoxicological effects of pharmaceuticals and other micropollutants released from wastewater treatment plants, activated carbon adsorption is one of the few processes to effectively reduce the concentrations of micropollutants in wastewater. Although aimed mainly at apolar compounds, polar compounds are also simultaneously removed to a certain extent, which has rarely been studied before. In this study, adsorption isotherm and batch kinetic data were collected with two powdered activated carbons (PACs) to assess the removal of the polar pharmaceuticals 5-fluorouracil (5-Fu) and cytarabine (CytR) from ultrapure water and wastewater treatment plant effluent. At pH 7.8, single-solute adsorption isotherm data for the weak acid 5-Fu and the weak base CytR showed that their adsorption capacities were about 1 order of magnitude lower than those of the less polar endocrine disrupting chemicals bisphenol A (BPA) and 17-α-ethinylestradiol (EE2). To remove 90 % of the adsorbate from a single-solute solution 14, 18, 70, and 87 mg L(-1) of HOK Super is required for EE2, BPA, CytR, and 5-Fu, respectively. Effects of solution pH, ionic strength, temperature, and effluent organic matter (EfOM) on 5-Fu and CytR adsorption were evaluated for one PAC. Among the studied factors, the presence of EfOM had the highest effect, due to a strong competition on 5-Fu and CytR adsorption. Adsorption isotherm and kinetic data and their modeling with a homogeneous surface diffusion model showed that removal percentage in the presence of EfOM was independent on the initial concentration of the ionizable compounds 5-Fu and CytR. These results are similar to neutral organic compounds in the presence of natural organic matter. Overall, results showed that PAC doses sufficient to remove >90 % of apolar adsorbates were able to remove no more than 50 % of the polar adsorbates 5-Fu and CytR and that the contact time is a critical parameter.
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Affiliation(s)
- Lubomira Kovalova
- Institute of Hygiene and Environmental Medicine, RWTH Aachen University, Pauwelstr. 50, 52074, Aachen, Germany
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Cork as a new (green) coating for solid-phase microextraction: Determination of polycyclic aromatic hydrocarbons in water samples by gas chromatography–mass spectrometry. Anal Chim Acta 2013; 772:33-9. [DOI: 10.1016/j.aca.2013.02.021] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Revised: 02/01/2013] [Accepted: 02/13/2013] [Indexed: 11/22/2022]
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12
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Hu E, Cheng H, Hu Y. Microwave-induced degradation of atrazine sorbed in mineral micropores. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:5067-5076. [PMID: 22489838 DOI: 10.1021/es204519d] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The herbicide atrazine is a common pollutant in reservoirs and other sources of drinking water worldwide. The adsorption of atrazine from water onto zeolites CBV-720 and 4A, mesoporous silica MCM-41, quartz sand, and diatomite, and its microwave-induced degradation when sorbed on these minerals, were studied. Dealuminated HY zeolite CBV-720 exhibited the highest atrazine sorption capacity among the mineral sorbents because of its high micropore volume, suitable pore sizes, and surface hydrophobicity. Atrazine sorbed on the minerals degraded under microwave irradiation due to interfacial selective heating by the microwave, while atrazine in aqueous solution and associated with PTFE powder was not affected. Atrazine degraded rapidly in the micropores of CBV-720 under microwave irradiation and its degradation intermediates also decomposed with further irradiation, suggesting atrazine could be fully mineralized. Two new degradation intermediates of atrazine, 3,5-diamino-1,2,4-triazole and guanidine, were first identified in this study. The evolution of degradation intermediates and changes in infrared spectra of CBV-720 after microwave irradiation consistently indicate the creation of microscale hot spots in the micropores and the degradation of atrazine following a pyrolysis mechanism. These results indicate that microporous mineral sorption coupled with microwave-induced degradation could serve as an efficient treatment technology for removing atrazine from drinking water.
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Affiliation(s)
- Erdan Hu
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
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13
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Cork-based activated carbons as supported adsorbent materials for trace level analysis of ibuprofen and clofibric acid in environmental and biological matrices. J Chromatogr A 2011; 1218:6263-70. [PMID: 21820664 DOI: 10.1016/j.chroma.2011.07.025] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Revised: 07/04/2011] [Accepted: 07/06/2011] [Indexed: 11/20/2022]
Abstract
In this contribution, powdered activated carbons (ACs) from cork waste were supported for bar adsorptive micro-extraction (BAμE), as novel adsorbent phases for the analysis of polar compounds. By combining this approach with liquid desorption followed by high performance liquid chromatography with diode array detection (BAμE(AC)-LD/HPLC-DAD), good analytical performance was achieved using clofibric acid (CLOF) and ibuprofen (IBU) model compounds in environmental and biological matrices. Assays performed on 30 mL water samples spiked at the 25.0 μg L(-1) level yielded recoveries around 80% for CLOF and 95% for IBU, under optimized experimental conditions. The ACs textural and surface chemistry properties were correlated with the results obtained. The analytical performance showed good precision (<15%), suitable detection limits (0.24 and 0.78 μg L(-1) for CLOF and IBU, respectively) and good linear dynamic ranges (r(2)>0.9922) from 1.0 to 600.0 μg L(-1). By using the standard addition methodology, the application of the present approach to environmental water and urine matrices allowed remarkable performance at the trace level. The proposed methodology proved to be a viable alternative for acidic pharmaceuticals analysis, showing to be easy to implement, reliable, sensitive and requiring low sample volume to monitor these priority compounds in environmental and biological matrices.
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Tsimas ES, Tyrovola K, Xekoukoulotakis NP, Nikolaidis NP, Diamadopoulos E, Mantzavinos D. Simultaneous photocatalytic oxidation of As(III) and humic acid in aqueous TiO2 suspensions. JOURNAL OF HAZARDOUS MATERIALS 2009; 169:376-85. [PMID: 19395168 DOI: 10.1016/j.jhazmat.2009.03.107] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2008] [Revised: 03/16/2009] [Accepted: 03/23/2009] [Indexed: 05/02/2023]
Abstract
The simultaneous photocatalytic oxidation of As(III) and humic acid (HA) in aqueous Degussa P25 TiO(2) suspensions was investigated. Preliminary photocatalytic studies of the binary As(III)/TiO(2) and HA/TiO(2) systems showed that As(III) was oxidized more rapidly than HA and the extent of photocatalytic oxidation of each individual component (i.e. As(III) or HA) increased with decreasing its initial concentration and/or increasing catalyst loading. The simultaneous photocatalytic oxidation of As(III) and HA in the ternary As(III)/HA/TiO(2) system showed that both As(III) and HA oxidation was reduced in the ternary system compared to the corresponding binary systems. The effect of operating conditions in the ternary system, such as initial As(III), HA and TiO(2) concentrations (in the range 3-20mg/L, 10-100mg/L and 50-250 mg/L respectively), initial solution pH (3.6-6.7) and reaction time (10-30 min), on photocatalytic As(III) and HA oxidation was assessed implementing a two-level factorial experimental design methodology. Seven and ten factors were found statistically important in the case of photocatalytic As(III) and HA oxidation respectively. Based on these statistically significant factors, a first order polynomial model describing As(III) and HA photocatalytic oxidation was constructed and a very good agreement was obtained between the experimental values and those predicted by the model, while the observed differences may be readily explained as random noise.
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Affiliation(s)
- Emmanuil S Tsimas
- Department of Environmental Engineering, Technical University of Crete, GR-73100 Chania, Greece
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