Enhanced Permeability, Selectivity, and Antifouling Ability of CNTs/Al2O3 Membrane under Electrochemical Assistance

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• 作者：Xinfei Fan ; Huimin Zhao ; Yanming Liu ; Xie Quan ; Hongtao Yu ; Shuo Chen
• 刊名：Environmental Science & Technology
• 出版年：2015
• 出版时间：February 17, 2015
• 年：2015
• 卷：49
• 期：4
• 页码：2293-2300
• 全文大小：401K
• ISSN：1520-5851

文摘

Membrane filtration provides effective solutions for removing contaminants, but achieving high permeability, good selectivity, and antifouling ability remains a great challenge for existing membrane filtration technologies. In this work, membrane filtration coupled with electrochemistry has been developed to enhance the filtration performance of a CNTs/Al₂O₃ membrane. The as-prepared CNTs/Al₂O₃ membrane, obtained by coating interconnected CNTs on an Al₂O₃ substrate, presented good pore-size tunability, mechanical stability, and electroconductivity. For the removal of a target (silica spheres as a probe) with a size comparable to the membrane pore size, the removal efficiency and flux at +1.5 V were 1.1 and 1.5 times higher, respectively, than those without electrochemical assistance. Moreover, the membrane also exhibited a greatly enhanced removal efficiency for contaminants smaller than the membrane pores, providing enhancements of 4 orders of magnitude and a factor of 5.7 for latex particles and phenol, respectively. These results indicated that both the permeability and the selectivity of CNTs/Al₂O₃ membranes can be significantly improved by electrochemical assistance, which was further confirmed by the removal of natural organic matter (NOM). The permeate flux and NOM removal efficiency at +1.5 V were about 1.6 and 3.0 times higher, respectively, than those without electrochemical assistance. In addition, the lost flux of the fouled membrane was almost completely recovered by an electrochemically assisted backwashing process.