Facile Synthesis of Electrically Conductive Membranes

Abstract

A facile and effective strategy that can be used to fabricate electrically conductive membranes (ECMs) of diverse filtration performance (i.e., water productivity and solute rejection) is not available yet. Herein, we report a facile method that enables the fabrication of ECMs of a broad performance range. The method is based on the use of polyethylenimine (PEI), glutaraldehyde, and any of a diverse set of conductive materials to cast an electrically conductive layer atop any of a diverse set of substrates (i.e., from microfiltration to reverse osmosis membranes). We developed the reported ECM fabrication method using graphite as the conductive material and PVDF membranes as substrates. We demonstrate that graphite-PVDF ECMs were stable and electrically conductive and could be successfully used for solute filtration and electrochemical degradation. We also confirmed that the PEI/glutaraldehyde-based ECM fabrication method is suitable for conductive materials other than graphite, including carbon nanotubes, reduced graphene oxide, activated charcoal, and silver nanoparticles. Compared with the substrates used for their fabrication, ECMs showed low electrical sheet resistances that varied with conductive material, increased solute rejection, and reduced water permeance. Taken together, this work presents a promising general strategy for the fabrication of ECMs for environmental applications from diverse substrates and conductive materials.