PTFE conductive membrane for EVMD process and the application of electro-catalysis

摘要

To inhibit membrane fouling and to overcome the disadvantages of traditional conductive membranes, polytetrafluoroethylene (PTFE) flat sheet membrane was used as the substrate to prepare a flexible conductive membrane. Multi-walled carbon nanotubes (MWCNTs) and mixture of MWCNTs/graphene (mass ratio 1:1) were employed as conductive layer. PTFE conductive membrane acted as a cathode which was applied in EVMD (Electric vacuum membrane distillation) process to mitigate membrane fouling. The MD flux increased from 4.97 to 8.89 L/m(2) h which was because of not only electric field repulsion but also the effect of electro-catalysis. MD flux recovered from 8.51 to 11.68 L/m(2) h after electrochemical cleaning (EC) for 4 h fixing electric field strength at 1.5 v/cm. Meanwhile PTFE conductive membrane was employed in electro-catalytic degradation experiment, in which nano-TiO2 was used as the electro-catalyst. In the electro-catalytic degradation experiment, the degradation rate of rhodamine red dye was up to 99.25%, and composite membranes exhibited good electro-catalytic stability. (C) 2017 Elsevier B.V. All rights reserved.