In-situ combined dual-layer CNT/PVDF membrane for electrically-enhanced fouling resistance.

Electrically conductive membrane possesses a remarkable performance in antifouling with the assistance of applied external electric fields. However, its widespread application is hampered due to the poor properties of existing conductive membranes, such as low conductivity and inadequate strength. The present study demonstrates a novel in-situ combination approach for the fabrication of a highly conductive carbon nanotube (CNT)/polyvinylidene fluoride (PVDF) membrane. During membrane fabrication, the casting solution film was pre-mantled with a CNT layer before the occurrence of polymer precipitation, thereby ensuring a natural and tight in-situ mergence between the CNT layer and supporting PVDF. The obtained CNT/PVDF membrane was characterized in terms of physicochemical properties and filtration performance. An electrically-enhanced cross-flow filtration system was devised to evaluate the antifouling performance of the pristine PVDF and CNT/PVDF membranes. Compared with the pristine PVDF membrane, the CNT/PVDF membrane possesses a greater electrical conductivity and a higher permeability. The incorporation of the CNT layer led to a completely different surface composition in terms of elemental components and functional groups. Being used as a cathode, the CNT/PVDF membrane exhibited a remarkable antifouling performance in the presence of external electric fields, and performed better in a 0 V/2 V-pulsed mode as compared with a 2 V-constant mode. This in-situ combination method provides a simple and practical approach for the fabrication of composite conductive membranes, suggesting promising applications in various membrane-fabrication areas. [ABSTRACT FROM AUTHOR]