Toward Improved Boron Removal in RO by Membrane Modification: Feasibility and Challenges

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• 作者：Roy Bernstein ; Sofia Belfer ; Viatcheslav Freger
• 刊名：Environmental Science & Technology
• 出版年：2011
• 出版时间：April 15, 2011
• 年：2011
• 卷：45
• 期：8
• 页码：3613-3620
• 全文大小：853K
• 年卷期：v.45,no.8(April 15, 2011)
• ISSN：1520-5851

文摘

Membrane modification by concentration polarization (CP)-enhanced radical graft polymerization using a dilute aqueous solution of appropriate monomer was examined as a method for increasing rejection of boric acid by reverse osmosis (RO) membranes. On the basis of suggested physicochemical rationales a number of monomers were examined in order to determine those with the lowest affinity toward boric acid as compared to water. The improvement in the modified membrane performance was mainly attributed to sealing less selective areas (鈥渄efects鈥? inherently present in the original low pressure RO (LPRO) membranes. However, the effect clearly differed for different monomers. Among the examined monomers glycidyl methacrylate (GMA) exhibited the lowest affinity and the largest improvement in removal of boric acid along with a moderate loss of permeability and slightly improved NaCl rejection. Modification of LPRO membrane thus resulted in a membrane with a permeability in the brackish water RO (BWRO) range but with removal of boric acid and salt superior to those reported for most commercial BWRO membranes.