Preparation and testing of polyvinyl alcohol composite membranes for reverse osmosis

Abstract

Thin film composite membranes were prepared by coating porous polysulfone membranes with a polyvinyl alcohol layer and further cross-linking its surface. The thin layer of crciss-linked polyvinyl alcohol served as a selective membrane. The membranes were prepared under various conditions and tested for sodium chloride separation. A high sodium chloride separation was achieved but the permeation rate was low compared with commercially available thin film composite membranes. Resistance against the flow of solvent water and sodium chloride solute were determined for individual component barrier layers.On a prtpart des membranes composites h film mince en recouvrant des membranes de polysulfone poreuses d'une couche d'alcool ployvinylique ayant subi une dticulation de surface. L a couche fine d'alcool polyvinylique ainsi prtparck sert de membrane stlective. Les membranes ont t t t prtpartes dans des conditions variks et testks pour la stparation du chlore de sodium. On a obtenu une separation 6levck du chlore de sodium mais la vitesse de permhtion est faible si on fait des comparaisons avec les membranes de composites h film mince disponibles sur le marcht. Les rtsistances h I'koulement d'eau (solvant) et du chlorure de sodium (:;olutt) ont t t t dtterminks pour des couches barritres de composants individuels.

Tuning the molecular structure, separation performance and interfacial properties of poly(vinyl alcohol)–polysulfone interfacial composite membranes

“…Cross-linked PVA membranes are appropriate for pressuredriven separations designed for a variety of water treatment applications including microfiltration [3] (for particle and bacteria removal), ultrafiltration [4,5] (for virus and macromolecule removal), nanofiltration (NF) [6] (for organic acid, small molecule and divalent metal removal), and reverse osmosis (RO) [7][8][9][10] (for desalination). In addition, cross-linked PVA membranes have been commercialized for dehydration of organic solvents by pervaporation; such membranes are prepared by coating a thin cross-linked PVA layer over polylacrylonitrile ultrafiltration membranes [11,12].…”

“…In addition, cross-linked PVA membranes have been commercialized for dehydration of organic solvents by pervaporation; such membranes are prepared by coating a thin cross-linked PVA layer over polylacrylonitrile ultrafiltration membranes [11,12]. While there have been many previous attempts to develop cross-linked PVA membranes for RO [7][8][9][13][14][15][16][17][18] and NF applications [10,19,20], none of these past formulations achieved commercial success because the membranes exhibited relatively low permeability and selectivity due to defect formation, improper cross-linking, or excessive thickness of PVA coating layers. These results were most commonly observed for surface cross-linking and dip-coating methods.…”

Study on a novel polyamide-urea reverse osmosis composite membrane (ICIC–MPD)I. Preparation and characterization of ICIC–MPD membrane

“…In general, the strategy that has been used extensively to improve the surface performance of RO membrane is to either develop the new materials of the skin layer or modify the surface of commercial RO membrane. For example, RO membranes of better antifouling ability have been obtained via changing the surface charge [3,4] or improving the hydrophilicity [5][6][7][8][9][10][11][12][13][14][15][16][17][18].…”

Poly (vinyl alcohol)/carboxymethyl cellulose sodium blend composite nanofiltration membranes developed via interfacial polymerization

“…To create stable membranes with good mechanical properties, and to improve the selective permeability, PVA must be insolubilized by cross-linking or other modification methods due to its water solubility [5]. There have been numerous literatures reported on the membranes based on cross-linked PVA, including microfiltration (MF) [6], ultrafiltration (UF) [7][8][9][10][11][12][13], NF [14][15][16][17], and RO membranes [18][19][20][21][22][23]. However, the permeate fluxes of the resultant PVA membranes were rarely satisfactory: most of the RO or NF membranes showed low permeate flux at high operating pressure.…”