3551
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3552
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Nguyen BTT, Toh CS. Development of an electrode-membrane-electrode system for selective Faradaic response towards charged redox species. Electrochim Acta 2009. [DOI: 10.1016/j.electacta.2009.01.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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3553
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Influence of surface modifying macromolecules on the surface properties of poly(ether sulfone) ultra-filtration membranes. J Memb Sci 2009. [DOI: 10.1016/j.memsci.2009.04.017] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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3554
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Vrouwenvelder J, van Paassen J, Kruithof J, van Loosdrecht M. Sensitive pressure drop measurements of individual lead membrane elements for accurate early biofouling detection. J Memb Sci 2009. [DOI: 10.1016/j.memsci.2009.04.016] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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3555
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Direct observation of bacterial deposition onto clean and organic-fouled polyamide membranes. J Colloid Interface Sci 2009; 336:13-20. [DOI: 10.1016/j.jcis.2009.03.063] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2008] [Revised: 03/28/2009] [Accepted: 03/30/2009] [Indexed: 11/21/2022]
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3556
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Nielsen CH. Biomimetic membranes for sensor and separation applications. Anal Bioanal Chem 2009; 395:697-718. [DOI: 10.1007/s00216-009-2960-0] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2009] [Revised: 07/02/2009] [Accepted: 07/07/2009] [Indexed: 01/04/2023]
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3557
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Suk ME, Aluru NR. Effect of induced electric field on single-file reverse osmosis. Phys Chem Chem Phys 2009; 11:8614-9. [PMID: 19774295 DOI: 10.1039/b903541a] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We investigated the effect of the electric field on single-file reverse osmosis (RO) water flux using molecular dynamics simulations. The electric field is generated by introducing oppositely charged biomolecules to the salt solution and pure water chambers attached to the nanopore. Simulation results indicate that an electric field in the direction of RO enhances the water flux while in the direction opposite to RO it suppresses the water flux. When the RO water flux is enhanced, the single-file water dipoles are aligned in the direction of the electric field. The addition of an electric field in the direction of RO led to a flux of 3 water molecules ns(-1) by constantly maintaining water dipole vectors in the direction of the electric field, and this water flux is superimposed on the pressure driven water flux.
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Affiliation(s)
- M E Suk
- Department of Mechanical Science and Engineering, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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3558
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Kim AS, Contreras AE, Li Q, Yuan R. Fundamental mechanisms of three-component combined fouling with experimental verification. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:7815-7827. [PMID: 19480394 DOI: 10.1021/la803706n] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The present article describes a novel fundamental theory for investigating combined fouling by colloids (STXL), macromolecules, and solute ions (NaCl). Three macromolecules were used for the combined fouling study, bovine serum albumin (BSA), alginate, and dextran. The presented theory unifies singlet, doublet, and triplet fouling phenomena, including cake-enhanced osmotic pressure and binary colloidal fouling models, giving rise to the combined flux equation for three-component fouling assuming a completely mixed fouling layer. The predicted combined flux was compared to two equivalent fluxes calculated from individual foulant contributions. The strong form of the equivalent flux, known as the additive flux, was based on a linear superposition of flux decline due to individual foulants. The weak form of equivalent flux assumed stratification of individual foulant layers and hence a linear superposition of the individual fouling resistance. A comparison of experimental data and theoretical calculations revealed that the weak form of equivalent flux and the combined flux that was predicted by the novel theory provided the upper and lower limits, respectively, of the observed permeate flux. Furthermore, the model simulation results suggested a structural compression of the BSA gel layer, whereas such a compression did not occur in cases of alginate and dextran. The gel concentrations of alginate and dextran in the combined fouling layer seemed to be less than those in the macromolecular gel layer.
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Affiliation(s)
- Albert S Kim
- Department of Civil and Environmental Engineering, University of Hawaii at Manoa, Honolulu, Hawaii 96822, USA
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3559
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Stewart TA, Trudell DE, Alam TM, Ohlin CA, Lawler C, Casey WH, Jett S, Nyman M. Enhanced water purification: a single atom makes a difference. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2009; 43:5416-5422. [PMID: 19708375 DOI: 10.1021/es803683t] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The aluminum Keggin polycation (Al13) has been identified as an effective specie for neutralization and coagulation of anionic contaminants in water. In this study, we compare efficacy of the aluminum Keggin-ion to the analogues containing a single Ga-atom or single Ge-atom (GaAl12 and GeAl12, respectively) substituted into the center of the polycation in water-treatment studies. We investigated removal of bacteriophage (model viruses), Cryptosporidium, dissolved organic carbon (DOC), and turbidity. In every study, the order of contaminant removal efficacy trends GaAl12 > Al13 > GeAl12. By ESI MS (electrospray ionization mass spectrometry), we noted the GaAl12 deprotonates least of the three aluminum polycations, and thus probably carries the highest charge, and also optimal contaminant-neutralization ability. The ESI MS studies of the aluminum polycation solutions, as well as solid-state characterization of their resulting precipitates both reveal some conversion of Al13 to larger polycations, Al30 for instance. The GaAl12 does not show any evidence for this alteration that is responsible for poor shelf life of commercial prehydrolyzed aluminum coagulants such as polyaluminum chloride. Based on these studies, we conclude that substitution of a single Ga-atom in the center of the aluminum Keggin polycation produces an optimal water-treatment product due to enhanced shelf life and efficacy in neutralization of anionic contaminants.
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Affiliation(s)
- Tom A Stewart
- Sandia National Laboratories, P.O. Box 5800 MS-0750, Albuquerque, New Mexico 87185, USA
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3560
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3561
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Herzberg M, Kang S, Elimelech M. Role of extracellular polymeric substances (EPS) in biofouling of reverse osmosis membranes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2009; 43:4393-8. [PMID: 19603652 DOI: 10.1021/es900087j] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
This study elucidates the mechanisms by which extracellular polymeric substances (EPS) impact permeate water flux and salt rejection during biofouling of reverse osmosis (RO) membranes. RO fouling experiments were conducted with Pseudomonas aeruginosa PAO1, EPS extracted from PAO1 biofilms, and dead PAO1 cells fixed in formaldehyde. While a biofouling layer of dead bacterial cells decreases salt rejection and permeate flux by a biofilm-enhanced osmotic pressure mechanism, the EPS biofouling layer adversely impacts permeate flux by increasing the hydraulic resistance to permeate flow. During controlled fouling experiments with extracted EPS in a simulated wastewater solution, polysaccharides adsorbed on the RO membranes much more effectively than proteins (adsorption efficiencies of 61.2-88.7% and 11.6-12.4% for polysaccharides and proteins, respectively). Controlled fouling experiments with EPS in sodium chloride solutions supplemented with 0.5 mM calcium ions (total ionic strength of 15 mM) indicate that calcium increases the adsorption efficiency of polysaccharides and DNA by 2- and 3-fold, respectively. The increased adsorption of EPS onto the membrane resulted in a significant decrease in permeate water flux. Corroborating with these calcium effects, atomic force microscopy (AFM) measurements demonstrated that addition of calcium ions to the feed solution results in a marked increase in the adhesion forces between a carboxylated particle probe and the EPS layer. The increase in the interfacial adhesion forces is attributed to specific EPS-calcium interactions that play a major role in biofouling of RO membranes.
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Affiliation(s)
- Moshe Herzberg
- Department of Desalination and Water Treatment, Zuckerberg Institute for Water Research, Ben-Gurion University of the Negev, Sede Boqer Campus 84990, Israel.
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3562
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Gikas P, Tchobanoglous G. Sustainable use of water in the Aegean Islands. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2009; 90:2601-2611. [PMID: 19243876 DOI: 10.1016/j.jenvman.2009.01.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2008] [Revised: 12/27/2008] [Accepted: 01/21/2009] [Indexed: 05/27/2023]
Abstract
Water demands in the Aegean Islands have increased steadily over the last decade as a result of a building boom for new homes, hotels, and resorts. The increase in water demand has resulted in the disruption of past sustainable water management practices. At present, most freshwater needs are met through the use of the limited groundwater, desalinated seawater, and freshwater importation. Wastewater reclamation, not used extensively, can serve as an alternative source of water, for a variety of applications now served with desalinated and imported water. Three alternative processes: desalination, importation, and water reclamation are compared with respect to cost, energy requirements and long-term sustainability. Based on the comparisons made, water reclamation and reuse should be components of any long-term water resources management strategy.
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Affiliation(s)
- Petros Gikas
- Department of Civil and Environmental Engineering, University of California at Davis, Engineering III, Davis, CA 95616, USA.
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3563
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Krogman KC, Lowery JL, Zacharia NS, Rutledge GC, Hammond PT. Spraying asymmetry into functional membranes layer-by-layer. NATURE MATERIALS 2009; 8:512-8. [PMID: 19377464 DOI: 10.1038/nmat2430] [Citation(s) in RCA: 129] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2008] [Accepted: 03/19/2009] [Indexed: 05/25/2023]
Abstract
As engineers strive to mimic the form and function of naturally occurring materials with synthetic alternatives, the challenges and costs of processing often limit creative innovation. Here we describe a powerful yet economical technique for developing multiple coatings of different morphologies and functions within a single textile membrane, enabling scientists to engineer the properties of a material from the nanoscopic level in commercially viable quantities. By simply varying the flow rate of charged species passing through an electrospun material during spray-assisted layer-by-layer deposition, individual fibres within the matrix can be conformally functionalized for ultrahigh-surface-area catalysis, or bridged to form a networked sublayer with complimentary properties. Exemplified here by the creation of selectively reactive gas purification membranes, the myriad applications of this technology also include self-cleaning fabrics, water purification and protein functionalization of scaffolds for tissue engineering.
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Affiliation(s)
- Kevin C Krogman
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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3564
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Peng X, Jin J, Nakamura Y, Ohno T, Ichinose I. Ultrafast permeation of water through protein-based membranes. NATURE NANOTECHNOLOGY 2009; 4:353-357. [PMID: 19498395 DOI: 10.1038/nnano.2009.90] [Citation(s) in RCA: 200] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2009] [Accepted: 03/23/2009] [Indexed: 05/27/2023]
Abstract
Pressure-driven filtration by porous membranes is widely used in the production of drinking water from ground and surface water. Permeation theory predicts that filtration rate is proportional to the pressure difference across the filtration membrane and inversely proportional to the thickness of the membrane. However, these membranes need to be able to withstand high water fluxes and pressures, which means that the active separation layers in commercial filtration systems typically have a thickness of a few tens to several hundreds of nanometres. Filtration performance might be improved by the use of ultrathin porous silicon membranes or carbon nanotubes immobilized in silicon nitride or polymer films, but these structures are difficult to fabricate. Here, we report a new type of filtration membrane made of crosslinked proteins that are mechanically robust and contain channels with diameters of less than 2.2 nm. We find that a 60-nm-thick membrane can concentrate aqueous dyes from fluxes up to 9,000 l h(-1) m(-2) bar(-1), which is approximately 1,000 times higher than the fluxes that can be withstood by commercial filtration membranes with similar rejection properties. Based on these results and molecular dynamics simulations, we propose that protein-surrounded channels with effective lengths of less than 5.8 nm can separate dye molecules while allowing the ultrafast permeation of water at applied pressures of less than 1 bar.
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Affiliation(s)
- Xinsheng Peng
- Organic Nanomaterials Center, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Japan
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3565
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Ma Z, Hong Y, Ma L, Su M. Superhydrophobic membranes with ordered arrays of nanospiked microchannels for water desalination. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:5446-5450. [PMID: 19341278 DOI: 10.1021/la900494u] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Membrane distillation can desalinate seawater using low-grade heat energy or solar heat, but it has limited mass fluxes and membrane fouling issues. Glass membranes with integrated arrays of nanospiked microchannels and a narrow pore size distribution are made through a process that involves glass fiber drawing, dissolving template material from microchannels and differential chemical etching. After surface modification, superhydrophobic glass membranes with water contact angles of over 160 degrees are produced because of the formations of ordered arrays of spiked nanostructures. The superhydrophobic membrane has shown better antifouling ability and higher flux than those of existing polymer membranes, especially at high salt concentration, owing to its large pore diameter, straight pore shape, narrow pore size distribution, high chemical and thermal stabilities, and water-repelling ability.
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Affiliation(s)
- Zeyu Ma
- NanoScience Technology Center, Department of Mechanical, Materials, and Aerospace Engineering, University of Central Florida, Orlando, Florida 32826, USA
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3566
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Manos M, Kanatzidis M. Sequestration of Heavy Metals from Water with Layered Metal Sulfides. Chemistry 2009; 15:4779-84. [DOI: 10.1002/chem.200900353] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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3567
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Liang S, Liu C, Song L. Two-step optimization of pressure and recovery of reverse osmosis desalination process. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2009; 43:3272-3277. [PMID: 19534146 DOI: 10.1021/es803692h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Driving pressure and recovery are two primary design variables of a reverse osmosis process that largely determine the total cost of seawater and brackish water desalination. A two-step optimization procedure was developed in this paper to determine the values of driving pressure and recovery that minimize the total cost of RO desalination. It was demonstrated that the optimal net driving pressure is solely determined by the electricity price and the membrane price index, which is a lumped parameter to collectively reflect membrane price, resistance, and service time. On the other hand, the optimal recovery is determined by the electricity price, initial osmotic pressure, and costs for pretreatment of raw water and handling of retentate. Concise equations were derived for the optimal net driving pressure and recovery. The dependences of the optimal net driving pressure and recovery on the electricity price, membrane price, and costs for raw water pretreatment and retentate handling were discussed.
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Affiliation(s)
- Shuang Liang
- College of Environmental Science and Engineering Shandong University 27 Shanda Nanlu, Jinan, Shandong 250100, China
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3568
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Yield stress and rheological characteristics of activated sludge in an airlift membrane bioreactor. J Memb Sci 2009. [DOI: 10.1016/j.memsci.2009.02.022] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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3569
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Padhye L, Tezel U, Mitch WA, Pavlostathis SG, Huang CH. Occurrence and fate of nitrosamines and their precursors in municipal sludge and anaerobic digestion systems. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2009; 43:3087-3093. [PMID: 19534118 DOI: 10.1021/es803067p] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The fate of six nitrosamines and their secondary amine precursors and total precursors in three municipal wastewater treatment plants' primary sludge (PS), waste-activated sludge (WAS), and anaerobic digester mixed liquor (ADML) was investigated. N-Nitrosodimethylamine was detected at significant concentrations, with mean concentrations at 678 +/- 302, 394 +/- 322, and 271 +/- 100 ng/L in PS, WAS, and ADML samples, respectively. N-Nitrosopyrrolidine was the other nitrosamine detected in sludge samples but at about an order of magnitude lower concentrations. PS samples also contained the highest concentrations of secondary amines(mostly dimethylamine (DMA) and pyrrolidine) followed by WAS and ADML samples, with mean DMA concentrations at 1280 +/- 689, 210 +/- 266, and 6.2 +/- 3.9 microg/L, respectively. Secondary amines in ADML and some WAS samples accounted for only 20-30% of total nitrosamine precursors underlining the significance of as of yet uncharacterized precursors. Overall, anaerobic sludge digestion was a sink for nitrosamines and secondary amines on the basis of the decreasing trends of these compounds from PS to WAS to ADML after taking mass balances into account An anaerobic bioassay conducted with ADML showed complete degradation of secondary amines even without additional carbon sources, while nitrosamine removal required carbon addition and was directly related to the chemical oxygen demand consumption.
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Affiliation(s)
- Lokesh Padhye
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
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3570
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Li G, Kang ET, Neoh KG, Yang X. Concentric hollow nanospheres of mesoporous silica shell-titania core from combined inorganic and polymer syntheses. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:4361-4364. [PMID: 19366218 DOI: 10.1021/la900756u] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Nearly monodispersed concentric hollow nanospheres with a mesoporous silica shell and anatase titania inner core were synthesized by the combination of sol-gel reaction and distillation-precipitation polymerization. The well-defined mesoporous concentric hollow nanospheres, comprising two nanostructured functional inorganics, can be used for confined catalytic reactions. The direct synthesis procedures can be readily extended to preparation of the concentric hollow nanospheres with multiple cores, or other functional concentric hollow nanospheres having different core-shell compositions.
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Affiliation(s)
- Guoliang Li
- Department of Chemical & Biomolecular Engineering, National University of Singapore, Kent Ridge, Singapore 119260
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3571
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Wang KY, Yang Q, Chung TS, Rajagopalan R. Enhanced forward osmosis from chemically modified polybenzimidazole (PBI) nanofiltration hollow fiber membranes with a thin wall. Chem Eng Sci 2009. [DOI: 10.1016/j.ces.2008.12.032] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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3572
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Meng F, Chae SR, Drews A, Kraume M, Shin HS, Yang F. Recent advances in membrane bioreactors (MBRs): membrane fouling and membrane material. WATER RESEARCH 2009; 43:1489-1512. [PMID: 19178926 DOI: 10.1016/j.watres.2008.12.044] [Citation(s) in RCA: 922] [Impact Index Per Article: 61.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2008] [Revised: 12/19/2008] [Accepted: 12/22/2008] [Indexed: 05/27/2023]
Abstract
Membrane bioreactors (MBRs) have been actively employed for municipal and industrial wastewater treatments. So far, membrane fouling and the high cost of membranes are main obstacles for wider application of MBRs. Over the past few years, considerable investigations have been performed to understand MBR fouling in detail and to develop high-flux or low-cost membranes. This review attempted to address the recent and current developments in MBRs on the basis of reported literature in order to provide more detailed information about MBRs. In this paper, the fouling behaviour, fouling factors and fouling control strategies were discussed. Recent developments in membrane materials including low-cost filters, membrane modification and dynamic membranes were also reviewed. Lastly, the future trends in membrane fouling research and membrane material development in the coming years were addressed.
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Affiliation(s)
- Fangang Meng
- Key Laboratory of Industrial Ecology and Environmental Engineering, MOE, School of Environmental and Biological Science and Technology, Dalian University of Technology, Dalian 116024, PR China.
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3573
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Liu Q, Ren W, Wang DW, Chen ZG, Pei S, Liu B, Li F, Cong H, Liu C, Cheng HM. In situ assembly of multi-sheeted buckybooks from single-walled carbon nanotubes. ACS NANO 2009; 3:707-713. [PMID: 19249871 DOI: 10.1021/nn800852n] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We report a simple approach for the direct and nondestructive assembly of multi-sheeted single-walled carbon nanotube book-like macrostructures (buckybooks) with good control of the nanotube diameter, the sheet packing density, and the book thickness during the floating catalytic growth process. The promise of such buckybooks is highlighted by demonstrating their high capacitance and high-efficiency molecular separation by directly using them as a binder-free electrode and as a filter, respectively. Our approach also provides a flexible and reliable way to easily assemble various other types of nanotubes into book-like or even more sophisticated sandwich-like hybrid macrostructures, realizing the shape-engineering of one-dimensional nanostructures to macroscopic well-defined architectures for various applications.
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Affiliation(s)
- Qingfeng Liu
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, People's Republic of China
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3574
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Shao Q, Zhou J, Lu L, Lu X, Zhu Y, Jiang S. Anomalous hydration shell order of Na+ and K+ inside carbon nanotubes. NANO LETTERS 2009; 9:989-994. [PMID: 19206198 DOI: 10.1021/nl803044k] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We performed molecular dynamics simulations of the hydration of Na+ and K+ in infinitely long single-walled armchair carbon nanotubes (CNTs) at 298 K. Simulation results indicate that the preferential orientation of water molecules in coordination shells of these two cations presents an anomalous change in the CNTs and causes a diameter-dependent variation for the interaction energy between the cation and water molecules in its coordination shell. In the five CNTs of this work, it is energetically favorable for confining a hydrated K+ inside the two narrow CNTs with diameters of 0.60 and 0.73 nm, whereas the situation is reverse inside the wide CNTs with diameters of 0.87, 1.0, and 1.28 nm. This finding is important for CNT applications in ionic systems that control the selectivity and the ionic flow.
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Affiliation(s)
- Qing Shao
- State Key Laboratory of Materials-oriented Chemical Engineering, Nanjing University of Technology, Nanjing 210009, People's Republic of China
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3575
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Lu CH, Huang CF, Kuo SW, Chang FC. Synthesis and Characterization of Poly(ε-caprolactone-b-4-vinylpyridine): Initiation, Polymerization, Solution Morphology, and Gold Metalation. Macromolecules 2009. [DOI: 10.1021/ma801413s] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Chu-Hua Lu
- Institute of Applied Chemistry, National Chiao Tung University, 30010 Hsinchu, Taiwan, and Department of Materials and Optoelectronic Science, Center for Nanoscience and Nanotechnology, National Sun Yat-Sen University, 804 Kaohsiung, Taiwan
| | - Chih-Feng Huang
- Institute of Applied Chemistry, National Chiao Tung University, 30010 Hsinchu, Taiwan, and Department of Materials and Optoelectronic Science, Center for Nanoscience and Nanotechnology, National Sun Yat-Sen University, 804 Kaohsiung, Taiwan
| | - Shiao-Wei Kuo
- Institute of Applied Chemistry, National Chiao Tung University, 30010 Hsinchu, Taiwan, and Department of Materials and Optoelectronic Science, Center for Nanoscience and Nanotechnology, National Sun Yat-Sen University, 804 Kaohsiung, Taiwan
| | - Feng-Chih Chang
- Institute of Applied Chemistry, National Chiao Tung University, 30010 Hsinchu, Taiwan, and Department of Materials and Optoelectronic Science, Center for Nanoscience and Nanotechnology, National Sun Yat-Sen University, 804 Kaohsiung, Taiwan
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3576
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Cheng H, Hu Y, Zhao J. Meeting China's water shortage crisis: current practices and challenges. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2009; 43:240-244. [PMID: 19238946 DOI: 10.1021/es801934a] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
China needs to and is undertaking several initiatives to conserve its water supply for human health and national productivity.
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Affiliation(s)
- Hefa Cheng
- State Key Laboratory of Pollution Control and Resources Reuse, Tongji University, Shanghai.
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3577
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Vrouwenvelder J, van Paassen J, van Agtmaal J, van Loosdrecht M, Kruithof J. A critical flux to avoid biofouling of spiral wound nanofiltration and reverse osmosis membranes: Fact or fiction? J Memb Sci 2009. [DOI: 10.1016/j.memsci.2008.09.029] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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3578
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3579
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Koehler FM, Rossier M, Waelle M, Athanassiou EK, Limbach LK, Grass RN, Günther D, Stark WJ. Magnetic EDTA: coupling heavy metal chelators to metal nanomagnets for rapid removal of cadmium, lead and copper from contaminated water. Chem Commun (Camb) 2009:4862-4. [DOI: 10.1039/b909447d] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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3580
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Vrouwenvelder JS, Hinrichs C, Van der Meer WGJ, Van Loosdrecht MCM, Kruithof JC. Pressure drop increase by biofilm accumulation in spiral wound RO and NF membrane systems: role of substrate concentration, flow velocity, substrate load and flow direction. BIOFOULING 2009; 25:543-555. [PMID: 19437193 DOI: 10.1080/08927010902972225] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In an earlier study, it was shown that biofouling predominantly is a feed spacer channel problem. In this article, pressure drop development and biofilm accumulation in membrane fouling simulators have been studied without permeate production as a function of the process parameters substrate concentration, linear flow velocity, substrate load and flow direction. At the applied substrate concentration range, 100-400 microg l(-1) as acetate carbon, a higher concentration caused a faster and greater pressure drop increase and a greater accumulation of biomass. Within the range of linear flow velocities as applied in practice, a higher linear flow velocity resulted in a higher initial pressure drop in addition to a more rapid and greater pressure drop increase and biomass accumulation. Reduction of the linear flow velocity resulted in an instantaneous reduction of the pressure drop caused by the accumulated biomass, without changing the biofilm concentration. A higher substrate load (product of substrate concentration and flow velocity) was related to biomass accumulation. The effect of the same amount of accumulated biomass on the pressure drop increase was related to the linear flow velocity. A decrease of substrate load caused a gradual decline in time of both biomass concentration and pressure drop increase. It was concluded that the pressure drop increase over spiral wound reverse osmosis (RO) and nanofiltration (NF) membrane systems can be reduced by lowering both substrate load and linear flow velocity. There is a need for RO and NF systems with a low pressure drop increase irrespective of the biomass formation. Current efforts to control biofouling of spiral wound membranes focus in addition to pretreatment on membrane improvement. According to these authors, adaptation of the hydrodynamics, spacers and pressure vessel configuration offer promising alternatives. Additional approaches may be replacing heavily biofouled elements and flow direction reversal.
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Affiliation(s)
- J S Vrouwenvelder
- Wetsus, Centre of Excellence for Sustainable Water Technology, Leeuwarden, The Netherlands.
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3581
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Abstract
A chemosensor array comprising 45 off-the-shelf colorimetric dyes, dubbed the Singapore Tongue (SGT), that is capable of discriminating different brands of bottled water and waters of different geographical attribute is described. Twelve kinds of bottled waters were tested by the SGT, and changes of absorbance spectra were analyzed by unsupervised classification methods to validate the SGT system for water analysis. All 12 bottled waters were discriminated at 1 × concentration, and SGT could distinguish the identity of samples of the waters diluted up to 100 times, except distilled waters. Following the study of 63 tap waters in different mass rapid transit stations in Singapore, two distinct clusters were observed from a principal component analysis plot, which correspond to the origin of the tap water. The successful discrimination and identification of in this study demonstrates the practical application of the SGT as a simple tool for water analysis.
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3582
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Manjón F, García-Fresnadillo D, Orellana G. Water disinfection with Ru(ii) photosensitisers supported on ionic porous silicones. Photochem Photobiol Sci 2009; 8:926-32. [DOI: 10.1039/b902014d] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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3583
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Vrouwenvelder JS, Manolarakis SA, van der Hoek JP, van Paassen JAM, van der Meer WGJ, van Agtmaal JMC, Prummel HDM, Kruithof JC, van Loosdrecht MCM. Quantitative biofouling diagnosis in full scale nanofiltration and reverse osmosis installations. WATER RESEARCH 2008; 42:4856-4868. [PMID: 18929382 DOI: 10.1016/j.watres.2008.09.002] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2008] [Revised: 08/13/2008] [Accepted: 09/02/2008] [Indexed: 05/26/2023]
Abstract
Biofilm accumulation in nanofiltration and reverse osmosis membrane elements results in a relative increase of normalised pressure drop (DeltaNPD). However, an increase in DeltaNPD is not exclusively linked to biofouling. In order to quantify biofouling, the biomass parameters adenosine triphosphate (ATP), total cell count and heterotrophic plate count in membrane elements were investigated during membrane autopsies and compared with DeltaNPD in test rigs and 15 full scale investigations with different types of feed water. The combination of biomass related parameters ATP and total cell count in membrane elements seem to be suitable parameters for diagnosis of biofouling, whereas plate counts were not appropriate to assess biofouling. The applied DeltaNPD measurement was too insensitive for early detection of fouling. Measurements of biological parameters in the water were shown to be not appropriate in quantifying biofouling. Evidently, there is a need for a practical tool, sensitive pressure drop data and systematic research.
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3584
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McGinnis RL, Elimelech M. Global challenges in energy and water supply: the promise of engineered osmosis. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2008; 42:8625-8629. [PMID: 19192773 DOI: 10.1021/es800812m] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
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3585
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Preparation of thin-film-composite polyamide membranes for desalination using novel hydrophilic surface modifying macromolecules. J Memb Sci 2008. [DOI: 10.1016/j.memsci.2008.07.037] [Citation(s) in RCA: 152] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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3586
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Li Q, Mahendra S, Lyon DY, Brunet L, Liga MV, Li D, Alvarez PJJ. Antimicrobial nanomaterials for water disinfection and microbial control: potential applications and implications. WATER RESEARCH 2008; 42:4591-4602. [PMID: 18804836 DOI: 10.1016/j.watres.2008.08.015] [Citation(s) in RCA: 1028] [Impact Index Per Article: 64.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2008] [Revised: 08/11/2008] [Accepted: 08/14/2008] [Indexed: 05/26/2023]
Abstract
The challenge to achieve appropriate disinfection without forming harmful disinfection byproducts by conventional chemical disinfectants, as well as the growing demand for decentralized or point-of-use water treatment and recycling systems calls for new technologies for efficient disinfection and microbial control. Several natural and engineered nanomaterials have demonstrated strong antimicrobial properties through diverse mechanisms including photocatalytic production of reactive oxygen species that damage cell components and viruses (e.g. TiO2, ZnO and fullerol), compromising the bacterial cell envelope (e.g. peptides, chitosan, carboxyfullerene, carbon nanotubes, ZnO and silver nanoparticles (nAg)), interruption of energy transduction (e.g. nAg and aqueous fullerene nanoparticles (nC(60))), and inhibition of enzyme activity and DNA synthesis (e.g. chitosan). Although some nanomaterials have been used as antimicrobial agents in consumer products including home purification systems as antimicrobial agents, their potential for disinfection or microbial control in system level water treatment has not been carefully evaluated. This paper reviews the antimicrobial mechanisms of several nanoparticles, discusses their merits, limitations and applicability for water disinfection and biofouling control, and highlights research needs to utilize novel nanomaterials for water treatment applications.
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Affiliation(s)
- Qilin Li
- Department of Civil and Environmental Engineering, Rice University, 6100 Main Street, Houston, TX 77005, USA
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3587
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Carter TG, Yantasee W, Sangvanich T, Fryxell GE, Johnson DW, Addleman RS. New functional materials for heavy metal sorption: "supramolecular" attachment of thiols to mesoporous silica substrates. Chem Commun (Camb) 2008:5583-5. [PMID: 18997959 DOI: 10.1039/b810576f] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new class of sorbent material, which exhibits exceptional metal capture from contaminated natural water, features aromatic thiol ligands reversibly bound to functionalized mesoporous silica through non-covalent interactions and have the potential of being regenerable.
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Affiliation(s)
- Timothy G Carter
- Department of Chemistry and Materials Science, University of Oregon, Eugene, OR 97403-1253, USA
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3588
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Mauter MS, Elimelech M. Environmental applications of carbon-based nanomaterials. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2008; 42:5843-59. [PMID: 18767635 DOI: 10.1021/es8006904] [Citation(s) in RCA: 653] [Impact Index Per Article: 40.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The unique and tunable properties of carbon-based nanomaterials enable new technologies for identifying and addressing environmental challenges. This review critically assesses the contributions of carbon-based nanomaterials to a broad range of environmental applications: sorbents, high-flux membranes, depth filters, antimicrobial agents, environmental sensors, renewable energy technologies, and pollution prevention strategies. In linking technological advance back to the physical, chemical, and electronic properties of carbonaceous nanomaterials, this article also outlines future opportunities for nanomaterial application in environmental systems.
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Affiliation(s)
- Meagan S Mauter
- Department of Chemical Engineering, Environmental Engineering Program, Yale University, P.O. Box 208286, New Haven, Connecticut 06520-8286, USA
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3589
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