Antifouling electrically conductive membrane for forward osmosis prepared by polyaniline/graphene nanocomposite

Abstract

Forward Osmosis (FO) has been listed as one of the best strategies to combat growing worldwide water scarcity. Not only FO, but all membrane-based technologies are still suffering from unpleasant fouling propensity, hindering their continuous performance in a long-term application. Using polyaniline (PANI) and graphene, herein, we fabricated a novel electro-conductive membrane (graphene/PANI laminated membrane, GPANILM) through laminating by facile pressure-assisted technique onto polyamide-imide (PAI) support layer. To improve the mechanical stability of the fabricated film via crosslinking of PANI with graphene nanosheetsthe membrane was thermal treated in 140 °C for 3 h (GPANILM-140). Both nanocomposite membranes (GPANILM and GPANILM-140) demonstrated excellent mechanical stability and their performances in terms of water permeation (JW) and reverse salt flux (Js) were verified using a regular FO desalination system. Our results showed that the selectivity ratios (Js/Jw) of GPANILM and GPANILM-140 membranes are 0.79 and 0.69 g/L in FO mode (top active layer of nanocomposite was facing to feed solution (FS)) and 0.67 and 0.58 g/L in PRO mode (PAI support layer was facing to FS), respectively. The anti-fouling behaviors of the electro-conductive membranes were investigated by a FS containing alginate as a model organic foulant. By applying 2 V anodic potential, both flux recovery rate (FRR) and fouling resistance were substantially improved in both membranes.