Download or read book Novel Surface Modifications and Materials for Fouling Resistant Water Purification Membranes written by Bryan David McCloskey and published by . This book was released on 2009 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt: A major challenge facing widespread implementation of membrane-based water purification is fouling, which results in increased operating costs and reduced membrane lifetime. This thesis focuses on various methods, including novel membrane surface modifications and polymers that resist degradation when exposed to oxidizing agents used as disinfectants, to alleviate membrane fouling. Fouling-resistant ultrafiltration membrane coatings were prepared from poly(ethylene glycol) diglycidyl ether-crosslinked chitosan (chi-PEG hybrid). Composite membranes were prepared for oil-water emulsion filtration by coating the most promising chi-PEG hybrid onto a polysulfone ultrafiltration membrane. Optimization of the coating layer thickness led to composite membranes that exhibited water flux values more than 5 times higher than that of uncoated membranes after one day of oily-water crossflow filtration. The organic rejection of the coated membranes was also higher than that of the uncoated polysulfone membranes. Polydopamine (PDOPA) deposition was discovered to reduce fouling in water purification membranes. PDOPA was found to deposit from solution onto virtually any surface. When deposited on water purification membranes, PDOPA rendered the membrane more hydrophilic and less susceptible to fouling. Moreover, covalent binding of other molecules, such as amine-terminated poly (ethylene glycol) (PEG), to PDOPA is simple and performed using benign chemicals and conditions. Commercially-available polymeric membranes were modified with polydopamine, and all showed improved fouling resistance while filtering oil-water emulsions. To demonstrate the versatility and ease of PDOPA modification scalability, PDOPA was deposited on entire membrane modules, and the resulting modified module exhibited improved fouling resistance. Finally, high ion rejection, chlorine-tolerant sulfonated polysulfone thin-film composite membranes were prepared and characterized. Interestingly, freestanding thick sulfonated poly(arylene ether sulfone) (BPS) films exhibit nearly neutral electrostatic charge, even though sulfonation introduces fixed negative charge into the polymer structure. As a result, charge exclusion ion partitioning is not a dominant rejection mechanism in these films. However, composite membranes prepared from a BPS coating layer and a porous Udel polysulfone support exhibit a negatively charged surface and, presumably, charge exclusion would be a more important partitioning mechanism for these membranes. Therefore, thick BPS films do not exhibit certain drawbacks, such as reduced salt rejection of mixed-valence feeds, that are observed in BPS thin-film composite membranes.
Download or read book Surface Modification of Water Purification Membranes to Improve Fouling Resistance in Oily Water Filtration written by Sirirat Kasemset and published by . This book was released on 2015 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the biggest challenges in using water purification membranes is fouling. Surface modification using hydrophilic materials can reduce hydrophobic interactions between membrane surface and hydrophobic foulants, thereby alleviating fouling. In this Ph.D. research, polydopamine (PDA), a highly hydrophilic and universal coating agent, was used to surface-modified reverse osmosis (RO) and ultrafiltration (UF) membranes. PDA modification conditions (e.g., dopamine coating solution concentration, coating time, and pH of coating solution) control PDA deposition and can directly influence the modified membrane properties. Thus, the influence of PDA modification conditions on membrane physical, permeation, selective, and fouling properties were investigated systematically. A fundamental understanding relating the physical and permeation properties and the fouling characteristics of PDA-modified membranes was established. The RO membranes were modified with PDA at various modification conditions. Permeate fluxes during pure water and oil/water emulsion filtrations were studied. The PDA modification increased the permeate fluxes during oil/water emulsion filtration (thus, improved membrane fouling resistance) relative to unmodified membranes regardless of the initial dopamine concentration or deposition time used. However, these changes were only observed for the membranes coated under alkaline conditions, suggesting that the PDA did not deposit well under acidic condition. For UF membranes, molecular weight cutoff (MWCO) and pure water permeance decreased with increasing initial dopamine concentration or deposition time. A permeability and selectivity tradeoff was also observed. Membrane mean pore size and pore size distribution (modeled using log-normal pore size distribution) were investigated via modelling using a hindered solute transport model, Hagen-Poiseuille equation, and a stagnant film model. The PDA modification increased UF membrane surface hydrophilicity regardless of the coating conditions used, but it did not clearly change surface roughness or zeta potential (i.e., surface charge). Membrane fouling propensity was characterized using threshold flux. Compared to unmodified membranes, the threshold flux increased at minimal PDA coatings, but decreased at excessive PDA coatings. These threshold flux changes were likely governed by a tradeoff between surface hydrophilicity increase and pure water permeance decrease. Excessive PDA coatings resulted in decreased pure water permeance and possibly, pore blockage and pore size reduction, leading to higher local permeate flux causing severe fouling and decreased threshold flux.
Download or read book Membrane Modification written by Nidal Hilal and published by CRC Press. This book was released on 2016-04-19 with total page 503 pages. Available in PDF, EPUB and Kindle. Book excerpt: Membrane Modification: Technology and Applications is written for engineers, scientists, graduate students, and researchers in the field of membrane science and technology, materials science, applied physics, chemistry, and environmental science. The book presents the complete range of membrane modification techniques used to increase efficiency of
Download or read book Functional Nanostructured Materials and Membranes for Water Treatment written by Mikel Duke and published by John Wiley & Sons. This book was released on 2013-03-14 with total page 343 pages. Available in PDF, EPUB and Kindle. Book excerpt: Membranes have emerged over the last 30 years as a viable water treatment technology. Earth's population is growing and the need for alternative ways to generate potable water is rising. The recent advent of nanotechnology opens the door to improving processes in membrane technology, which is a promising step on the way to solving the earth's potable water problem. Current performance is enhanced and new concepts are possible by engineering on the nanoscale. This book presents key areas of nanotechnology such as fouling tolerant and robust membranes, enhanced destruction of pollutants and faster monitoring of water quality. 'Functional Nanostructured Materials and Membranes for Water Treatment' is part of the series on Materials for Sustainable Energy and Development edited by Prof. G.Q. Max Lu. The series covers advances in materials science and innovation for renewable energy, clean use of fossil energy, and greenhouse gas mitigation and associated environmental technologies.
Download or read book Fouling resistant Coating Materials for Water Purification written by Yuan-hsuan Wu and published by . This book was released on 2009 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt: Membrane technology has been used in water purification for decades. However, membrane fouling remains a limiting factor. One way to control fouling is through surface modification. Several studies report that increasing surface hydrophilicity can reduce membrane fouling. Surface modification via physical coating (i.e., thin-film composite membrane) was explored in this research to prevent membrane fouling. Before making thin-film composite membranes, it was important to study structure/property relations in a series of potential coating materials. This research aims to contribute to a better fundamental understanding of the structure/property relations which govern water transport, rejection of model foulants (i.e., emulsified oil droplet or protein), and fouling characteristics in hydrogels based on poly(ethylene glycol) diacrylate (PEGDA) and N-vinyl-2-pyrrolidone (NVP). Crosslinked poly(ethylene glycol) (PEG) free-standing films were prepared by UV-induced photopolymerization of PEGDA crosslinker in the presence of varying amounts of water or monofunctional poly(ethylene glycol) acrylate (PEGA). The crosslinked PEGDA films exhibited polymerization induced phase separation (PIPS) when the water content of the prepolymerization mixture was greater than 60 wt%. Visible light absorbance measurements, water uptake, water permeability, and salt kinetic desorption experiments were used to characterize the structure of these phase-separated, crosslinked hydrogels. The films with PIPS exhibited a porous morphology in cryogenic scanning electron microscope (CryoSEM) studies. Dead-end filtration experiments using deionized water and bovine serum albumin (BSA) solutions were performed to explore the fundamental transport and fouling properties of these materials. The total flux of pure water through the films after prior exposure to BSA solution was nearly equal to that of the as-prepared material, indicating that these PEGDA films resist fouling by BSA under the conditions studied. Crosslinked NVP free-standing films were prepared by UV-induced photopolymerization in the presence of water, with NVP as the monomer and N, N'-methylenebisacrylamide (MBAA) as the crosslinker. A series of crosslinked films were polymerized at various prepolymerization water contents, NVP/MBAA ratios and at various levels of UV light intensity in the polymerization. Like PEGDA, the NVP films also underwent phase-separation during polymerization. The influence of monomer/ crosslinker ratio, prepolymerization water content, and UV intensities on membrane morphology and water transport was characterized with CryoSEM, bio-atomic force microscope (Bio-AFM) and dead-end filtration. Molecular weight cutoff (MWCO) measurements were used to characterize the sieving property of crosslinked NVP films polymerized at different UV intensities. UV intensity was found to have an impact on the interconnectivity of crosslinked membranes. Finally, tests of fouling resistance to protein solution (bovine serum albumin) and oily water emulsion were performed. The NVP crosslinked films had good protein and oily water fouling resistance. Overall, both crosslinked PEGDA and NVP films exhibit fouling resistance to oily water emulsions or protein solution. NVP films had more porous structure and higher water permeability than did PEGDA films, while the more compact structure of PEGDA films led to better rejection of model foulants (e.g., protein) than in NVP films. Based on different applications (e.g., oil/water separation, protein filtration), different coating materials must be chosen according to the membrane morphology, transport property, and rejection of model foulants to achieve the highest water flux and foulant rejection in membranes used for water purification.
Download or read book Novel Fouling Reducing Coatings for Ultrafiltration Nanofiltration and Reverse Osmosis Membranes written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Polymeric membranes could potentially be the most flexible and viable long-term strategy for treatment of produced water from oil and gas production. However, widespread use of membranes, including reverse osmosis (RO) membranes, for produced water purification is hindered due to fouling caused by the impurities present in the water. Fouling of RO membranes is likely caused by surface properties including roughness, hydrophilicity, and charge, so surface modification is the most widely considered approach to improve the fouling properties of current RO membranes. This project focuses on two main approaches to surface modification: coating and grafting. Hydrophilic coating and grafting materials based on poly(ethylene glycol) (PEG) are applied to commercial RO membranes manufactured by Dow FilmTec and GE. Crossflow filtration experiments are used to determine the fouling resistance of modified membranes, and compare their performance to that of unmodified commercial RO membranes. Grafting and coating are shown to be two alternative methods of producing modified membranes with improved fouling resistance.
Download or read book Assessment of Fouling in Native and Surface modified Water Purification Membranes written by Daniel Joseph Lang Miller and published by . This book was released on 2013 with total page 772 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fouling is a major obstacle to the implementation of membranes in water purification applications. Hydrophilization of the membrane surface tends to mitigate fouling because hydrophobic interactions between foulants and the membrane are reduced. Polydopamine was deposited onto membranes to render their surfaces hydrophilic. The chemical structure of polydopamine, which was previously ambiguous, was investigated by many spectroscopic techniques. While previously thought to consist of covalently-linked monomers, polydopamine was found to be an aggregate of partly-oxidized dopamine units linked by strong, non-covalent secondary interactions. Polydopamine was also used as a platform for the molecular conjugation of other anti-fouling materials, such as poly(ethylene glycol), to the membrane surface. Membrane fouling was assessed by constant permeate flux crossflow filtration with an oil/water emulsion feed. The threshold flux--the flux at which the rate of fouling significantly increases--was determined by a well-established flux stepping technique. Membrane resistance evolution during fouling was compared for constant flux and constant transmembrane pressure operation using unmodified membranes. Below the threshold flux (slow fouling), good agreement in resistance evolution was found between the two operational modes; above the threshold flux, significant deviation was observed. The effect of polydopamine and polydopamine-g-poly(ethylene glycol) surface modifications was studied under constant flux crossflow fouling conditions. The surface modifications were found to increase the membrane resistance, resulting in higher transmembrane pressures in the modified membranes than in the unmodified membranes at fluxes below the threshold flux. Modified membranes were also compared to unmodified membranes with the same pure water permeance (same initial resistance). In this case, the modified membranes had lower transmembrane pressures during fouling than the unmodified membranes, suggesting that a preferred method of membrane surface modification is to begin with a membrane of higher permeance than required, and then surface-modify it to achieve the desired permeance. The efficacy of polydopamine and polydopamine-g-poly(ethylene glycol) surface modifications in reducing biofouling was also evaluated. Modified membranes showed reduced protein and bacterial adhesion in short-term tests, which are commonly used to assess biofouling propensity. However, long-term operation under hydrodynamic conditions mimicking those of an industrial module showed no benefit of the hydrophilic coatings in limiting biofouling.
Download or read book Advanced Materials for Membrane Fabrication and Modification written by Stephen Gray and published by CRC Press. This book was released on 2018-08-30 with total page 621 pages. Available in PDF, EPUB and Kindle. Book excerpt: Membranes are an energy efficient separation technology that are now the basis for many water treatment and food processing applications. However, there is the potential to improve the operating performance of these separations and to extend the application of membranes to energy production, gas separations, organic solvent-based separations, and biomedical applications through novel membrane materials. This book contains 20 chapters written by leading academic researchers on membrane fabrication and modification techniques and provides a comprehensive overview on the recent developments of membrane technology. Membranes can be manufactured from a range of materials including polymeric compounds, and ceramic materials, and both these materials are considered in the book. There are 5 chapters on water and wastewater membranes that cover the fabrication of thin film (TFC) composite membranes for nanofiltration(NF)/reverse osmosis (RO)/forward osmosis (FO) applications, stimuli responsive membranes, electrospun membranes, porous ceramic membranes, and polymeric ultrafiltration (UF) manufacture and modification. There are another 6 chapters on gas separation that consider carbon membranes, zeolite membranes, silica template and metal oxide silica membranes, TFC membranes, silica membranes, and metal organic framework (MOF) membranes. Zeolite membranes are also considered for organic solvent applications, as are solvent-resistant membranes manufactured by phase inversion, ceramic-supported composite membranes, and ceramic NF membranes. The emerging areas of membranes for energy and biomedical applications have 3 and 2 chapters, respectively. Energy applications consider ion exchange membranes for use in fuel cells, membranes for electrodialysis, and membranes for use in microbial fuel cells. For biomedical applications the chapters focus on hemodialysis membranes and redox responsive membranes.
Download or read book Membrane Fouling written by Alon Yeshayahu Kirschner and published by . This book was released on 2019 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt: Membrane systems are used for water treatment in many industries due to their small footprint, low chemical and energy use, and ease of operation. However, membrane fouling remains a challenge, especially for highly concentrated feeds. Fouling increases hydraulic resistance, lowers water permeance and increases energy consumption. Fouled membranes require expensive cleaning or replacement, increasing operating costs. This study focuses on understanding fouling mechanisms in constant flux crossflow operation, commonly used in industry, and on development of novel fouling-resistant membrane coatings. A model combining two accepted fouling mechanisms, intermediate pore blocking and cake filtration, was developed to describe fouling in constant flux crossflow ultrafiltration (UF). The model was fit to experimental fouling results using rigid and deformable particles. Observations of the model's accuracy at different fluxes shed light on the physical meaning of the threshold flux: the threshold flux is the flux below which cake buildup is negligible and above which cake filtration becomes the dominant fouling mechanism. Further development of the model may enable fouling prediction. To mitigate fouling in oil-water separations, two novel membrane coatings were developed. The first coating was based on polydopamine (PDA), a well-established fouling-resistant coating material. Poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC), a polymer zwitterion, was co-deposited with PDA to form a composite coating on polysulfone (PS) UF membranes. Fouling experiments showed that addition of PMPC to PDA significantly improved fouling resistance. The difference in fouling performance is likely due to the strongly hydrophilic surface properties contributed by PMPC. The co-deposition method opens opportunities for expansion of the concept in which PDA acts as a robust platform for the integration of non-fouling co-adsorbates. The second coating addresses a weakness of PDA coatings - their sensitivity to aqueous chlorine. Chlorine is widely used as a disinfectant in water purification processes. Chlorine oxidation results in rapid removal of PDA coatings from membrane surfaces, rendering them vulnerable to fouling. Poly(N-methylaniline) (PNMA) is a polyaniline derivative which contains a tertiary amine, rather than a secondary amine as in PDA, making PNMA less vulnerable to chlorine oxidation. PNMA-modified membranes were more stable and had higher fouling resistance than PDA-modified membranes after chlorine exposure
Download or read book Polymeric Membranes for Water Purification and Gas Separation written by Rasel Das and published by Materials Research Forum LLC. This book was released on 2021-11-25 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt: Various organic and synthetic polymers are important materials for the removal of organic and inorganic pollutants from wastewater and the separation of gases. The book discusses various types of membranes for microfiltration, ultrafiltration, nanofiltration, reverse osmosis, forward osmosis etc. A number of nanomaterials are available for the modification of polymeric membranes. Keywords: Polymeric Membrane, Water Purification, Water Softening, Water Desalination, Gas Separation, Osmosis Membranes, Microfiltration, Ultrafiltration, Nanofiltration, Carbon Nanotube, Nanosheets, MOFs, Porous Organic Cages, Titanium Dioxide, Zinc Oxide, Mesoporous Silica Nanoparticles, O2/N2 Separation, CO2/CH4 Separation, H2/N2 Separation.
Download or read book Enhancement of Membrane Fouling Resistance Through Surface Modification written by Michelle Chapman Wilbert and published by . This book was released on 1997 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Surface Modification of Polymer Membranes by Self organization written by Jonathan Forrest Hester and published by . This book was released on 2001 with total page 295 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Novel Fouling resistant Membranes for Water Purification written by Hao Ju and published by . This book was released on 2008 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Membranes for Water Treatment written by Klaus-Viktor Peinemann and published by John Wiley & Sons. This book was released on 2010-11-29 with total page 251 pages. Available in PDF, EPUB and Kindle. Book excerpt: This ready reference on Membrane Technologies for Water Treatment, is an invaluable source detailing sustainable, emerging processes, to provide clean, energy saving and cost effective alternatives to conventional processes. The editors are internationally renowned leaders in the field, who have put together a first-class team of authors from academia and industry to present a highly approach to the subject. The book is an instrumental tool for Process Engineers, Chemical Engineers, Process Control Technicians, Water Chemists, Environmental Chemists, Materials Scientists and Patent Lawyers.
Download or read book Membranes for Water Treatment and Remediation written by Ashok Kumar Nadda and published by Springer Nature. This book was released on 2023-03-03 with total page 299 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides comprehensive description of polymeric membranes in water treatment and remediation. It describes both the sustainability challenges and new opportunities to use membranes for water decontamination. It also discusses the environmental-related issues, challenges and advantages of using membrane-based systems and provides comprehensive description of various polymeric membranes, nanomaterials, biomolecules and their integrated systems for wastewater treatment. Various topics covered in this book are direct pressure-driven and osmotic-driven membrane processes, hybrid membrane processes (such as membrane bioreactors and integrating membrane separation with other processes), and resource recovery-oriented membrane-based processes. The book will be useful for students, researchers and professionals working in the area of materials science and environmental chemistry.
Download or read book Improving the Transport Properties and Fouling Resistance of Commercial Water Treatment Membranes Through Ion Beam Irradiation Surface Modifications written by Kevin Good and published by . This book was released on 2002 with total page 374 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Polymeric Membrane Bacterial Attachment Strategies written by Sweta Binod Kumar and published by . This book was released on 2023-09-28 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polymeric membranes are extensively used in various applications such as water treatment, wastewater treatment, desalination, and other filtration processes. However, their performance is often compromised due to the attachment of bacteria on their surfaces, leading to biofouling and membrane fouling. Therefore, developing strategies to control bacterial attachment on polymeric membranes is crucial for maintaining their efficiency and longevity. In this book, Several Strategies have been explore to minimize bacterial attachment, including surface modifications to make the membranes more antifouling, self-cleaning, and resistant to biofilm formation. These modifications can be achieved through the incorporation of hydrophilic, hydrophobic, or zwitterionic materials, as well as using nanotechnology-based methods. Biocides and disinfectants have also been used to prevent bacterial attachment, although their usage is limited due to environmental concerns. Cleaning the membranes is also an important aspect of maintaining their performance. Membrane cleaning methods such as filtration, ultrafiltration, nanofiltration, and reverse osmosis can help remove bacteria and other contaminants from the membrane surface. However, frequent cleaning can also damage the membrane and reduce its lifespan, highlighting the need for fouling-resistant membranes. Membrane bioreactors have emerged as a promising alternative to traditional wastewater treatment methods. In this process, biofilm formation on the membrane surface is encouraged to promote biodegradation of organic matter. Bio-inspired materials that mimic the surface charge, surface energy, and surface topography of biological organisms have also been developed to minimize bacterial adhesion. The attachment of bacteria on the membrane surface is influenced by various factors, including surface charge, surface energy, surface topography, microbial communities, and extracellular polymeric substances (EPS). Quorum sensing and other signaling mechanisms also play a critical role in the formation of biofilms. Therefore, understanding the microbial ecology and physiology is crucial for developing effective strategies to control bacterial attachment. Overall, the control of bacterial attachment on polymeric membranes is a complex issue that requires a multidisciplinary approach. Strategies to prevent biofouling and membrane fouling should be developed while considering environmental impact, biodegradation, and the antimicrobial resistance of bacteria. The use of microbial adhesion and microbial physiology research can aid in the development of new strategies for effective bacterial attachment control.
