Enhanced Permeability and Removal Efficiency for Phenol and Perfluorooctane Sulphonate by a Multifunctional CNT/Al₂O₃ Membrane with Electrochemical Assistance.

Abstract

Membrane separation is recognized to be a promising technology for addressing water crisis. Unfortunately, the emergence of membrane fouling and low removal efficiency makes it unattractive for practical application. Herein, an electrochemical multifunctional CNT/Al₂O₃ membrane was designed coupled multiple electrochemical functions with pore sieving, which could maintain high permeability and achieve good removal efficiency simultaneously, even for those molecules with size smaller than pore size. The multifunctional CNT/Al₂O₃ membrane possessing a pore size of 140 nm and pure water flux of 869.6 L · m-2 · h-1 · bar-1 was prepared. The results show that the multifunctional CNT/Al₂O₃ membrane exhibited a good anti-fouling properties for both bio-fouling and chemical fouling under electrochemical assistance with a permeability 3.6 and 1.5 times higher than those of CNT/Al₂O₃ membrane alone for the treatment of E. coli and humic acid, respectively. In addition, the CNT/Al₂O₃ membrane with electrochemical assistance also shows a high removal efficiency for the treatment of perfluorooctane sulphonate (PFOS) and phenol whose sizes are smaller than pore size. As for the treatment of surface water, it also presented a good performance. Finally, the regeneration of the membrane was investigated and the fouled membrane was reused through an electrochemical assisted back-wash method.