Development of forward osmosis membranes modified by cross-linked layer by layer assembly for brackish water desalination (original) (raw)
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In this work, a novel surface modification strategy was developed to modify polyethersulfone membrane sub-strate to create membranes for forward osmosis applications. A novel poly(ethylenimine) crosslinked Hexadecafluorodecanedioic acid polyelectrolyte was synthesized, followed by layer deposition on the surface of an ultrafiltration membrane substrate. While the unmodified membrane was negatively charged, this procedure reversed the surface charge, leading to a positively charged forward osmosis-nanofiltration membrane. Interestingly, at pH 7, the zeta potential approached 6.9 mV for membrane coated 4.5 as compared to the pristine membrane with a zeta potential value of approximately −11.0 mV. Extensive characterization and chemical analyses were carried out to ensure the effectiveness of the developed separation layer. The results revealed that the poly(ethylenimine) crosslinked Hexadecafluorodecanedioic acid was successfully deposited on the poly-ethersulfone membrane substrate. Preparation conditions, such as curing temperature and time were optimized. It was found out that membrane coated with 3.5 bilayers and cured at 60 °C for one hour exhibited optimal water permeability of 21.9 L m −2 h −1 bar-1 of and solute permeability of 1.66 L m −2 h −1 as compared to the neat membrane.
Improved membrane structures for seawater desalination by studying the influence of sublayers
Desalination, 2012
This study describes the influence of polyethersulfone (PES) sublayers on the performance of polyamide (PA) reverse osmosis membranes. Asymmetric polymeric sublayers were synthesized by using the DIPS technique (Diffusion Induced Phase Separation). Sublayers are optimized mainly with respect to hydrophilicity, permeability and rejection potential by adjusting synthesis procedures. Parameters that were found to have an influence are the type of solvent (DMF and NMP were used), the air humidity, processing time, and concentrations of polymer. By carefully controlling these parameters, it was possible to prepare a range of sublayers with different characteristics, in the ultrafiltration-nanofiltration area. To visualize membrane surface characteristics, both scanning electron microscopy (SEM) and atomic force microscopy (AFM) measurements were performed. In addition, titanium (TiO 2 ) nanoparticles were assembled with polyethersulfone (PES) membranes at ultralow concentrations of nanoparticles to characterize TiO 2 /PES composite membranes and evaluate their permeate flux and solute rejection. Subsequently, a polyamide top layer was added by interfacial polymerization using typical reagents both in the aqueous and in the organic phase. The membrane performance was evaluated in terms of flux and salt rejection. Experimental design was performed in order to obtain the importance of some experimental variables during the polymerisation process. It was found that depending on the type of sublayer used in the procedure, a different membrane performance could be obtained.
Innovative Nanostructured Membranes for Reverse Osmosis Water Desalination
University of the Future: Re-Imagining Research and Higher Education
Reverse osmosis (RO) is considered as the most widely utilized technique worldwide for water treatment. However, the commercial thin-film composite (TFC) membranes, which are normally made of polyamide (PA) through interfacial polymerization (IP), still experience certain major issues in performance and fabrication. The spin assisted layer-by-layer (SA-LbL) technique was established for overcoming some drawbacks with commercially available PA membranes. Also, recent investigations have recognized the nanoparticle inclusion into the selective layer as a powerful technique for improving the membrane efficiency. Hence, two different methodologies are presented here to improve the membrane performance, i.e., (1) SA-LbL technique to fabricate TFC membrane by the deposition of alternate ultrathin layers of different polyelectrolytes on polysulfone (PSF) commercial ultrafiltration membrane and (2) the nanoclay incorporation into the membranes during IP process to develop TFC membrane. Two ...
Reverse Osmosis Membranes for Desalination of Brackish Water
University of Waterloo, 2020
Reverse osmosis (RO), which is commonly used for different water purification and desalination applications, is a remarkable process to separate dissolved inorganic and organic compounds from water. Over traditional methods of water treatment and purification, RO has many benefits such as production of high quality drinking water, simultaneous elimination of multiple pollutants, and simple operation procedure. As drinking water supplies are declining and demand for high quality water is increasing worldwide, RO membrane based water treatments will most probably continue to develop. This research was aimed at better understanding the behavior of the thin film composite (TFC) polyamide membrane used in RO process under various operating conditions. The performance of RO membrane was evaluated in terms of salt rejection and water flux to simulate brackish water desalination process. The operating conditions included salt concentrations ranging from 2000 to 6000 ppm and operating pressure ranging from 100 to 250 psi. Based on experimental results, the performance of the TFC polyamide RO membrane was estimated at higher operating pressures (300-1000 psi). Based on mass transfer coefficient , solute transport parameter and water permeability that is characteristic of the membrane. In addition, the potential of using the TFC RO membrane to process water during oil and gas productions (with 1.5-2.5 % salt by weight), was demonstrated in this study. Besides simulation, experiments were conducted using real water as the feed solution. Dedication This is dedicated to the one I love. v Table of Contents List of Figures viii List of Tables x List of Tables 2.1 Classification of pressure driven membrane separation processes[9].. .. . .
Membrane and Desalination Technologies
Handbook of Environmental Engineering, Volume 13, 2010
Lawrence K. Wang, Jiaping Paul Chen, Yung-Tse Hung, Nazih K. Shammas (2010), Membrane and Desalination Technologies, Humana Totowa, NJ, USA, 716 pages, ISBN 978-1-58829-940-6 , https://doi.org/10.1007/978-1-59745-278-6 ..... ABSTRACT: This book includes the following chapters: (1) Membrane Technology: Past, Present and Future; (2) Preparation of Polymeric Membranes; (3) Advanced Membrane Fouling Characterization in Full-Scale Reverse Osmosis Processes; (4) Membrane Filtration Regulations and Determination of Log Removal Value; (5) Treatment of Industrial Effluents, Municipal Wastes, and Potable Water by Membrane Bioreactors; (6) Treatment of Food Industry Foods and Wastes by Membrane Filtration; (7) Membrane Separation: Basics and Applications; (8) Membrane Systems Planning and Design; (9) Adsorption Desalination: A Novel Method; (10) Membrane Processes for Reclamation of Municipal Wastewater; (11) Potable Water Biotechnology, Membrane Filtration and Biofiltration; (12) Desalination of Seawater by Thermal Distillation and Electrodialysis Technologies; (13) Desalination of Seawater by Reverse Osmosis; (14) Membrane Technologies for Point-of-Use and Point-of-Entry Applications; (15) Membrane Technologies for Oil–Water Separation; and (16) Gas-Sparged Ultrafiltration: Recent Trends, Applications and Future Challenges.
Forward Osmosis Membrane: Review of Fabrication, Modification, Challenges and Potential
Membranes, 2023
Forward osmosis (FO) is a low-energy treatment process driven by osmosis to induce the separation of water from dissolved solutes/foulants through the membrane in hydraulic pressure absence while retaining all of these materials on the other side. All these advantages make it an alternative process to reduce the disadvantages of traditional desalination processes. However, several critical fundamentals still require more attention for understanding them, most notably the synthesis of novel membranes that offer a support layer with high flux and an active layer with high water permeability and solute rejection from both solutions at the same time, and a novel draw solution which provides low solute flux, high water flux, and easy regeneration. This work reviews the fundamentals controlling the FO process performance such as the role of the active layer and substrate and advances in the modification of FO membranes utilizing nanomaterials. Then, other aspects that affect the performance of FO are further summarized, including types of draw solutions and the role of operating conditions. Finally, challenges associated with the FO process, such as concentration polarization (CP), membrane fouling, and reverse solute diffusion (RSD) were analyzed by defining their causes and how to mitigate them. Moreover, factors affecting the energy consumption of the FO system were discussed and compared with reverse osmosis (RO). This review will provide in-depth details about FO technology, the issues it faces, and potential solutions to those issues to help the scientific researcher facilitate a full understanding of FO technology.
Membrane technologies for water treatment and agroindustrial sectors
Comptes Rendus Chimie, 2009
Although water is essential for human survival and progress, it is distributed very unevenly and with a different purity over the surface of the earth. A variety of contaminants can be present in raw water, depending on its origin. The size of these contaminants ranges from the micrometer (e.g. bacteria) to the tenths of a nanometer order (ions). Membrane processes like microfiltration, ultrafiltration, nanofiltration and reverse osmosis could be a solution for an advanced physical treatment of water for drinking purposes as well as for agroindustrial sectors. Many applications are well assessed and are expanding very quickly; however, to obtain an ever-growing performance, it is necessary to prepare membranes with tailored structure and transport properties. Characterisation methods play also a role of paramount importance for the selection of the more appropriate membrane for the above-mentioned applications. In this work the main membrane preparation techniques and characterisation methods will be reviewed and discussed. To cite this article: A.