Anti-Fouling Electroconductive Forward Osmosis Membranes: Electrochemical and Chemical Properties

Forward osmosis (FO) has been emerging and gaining attention within the membrane-based processes because it can achieve high water fluxes while minimizing energy consumption, making it a cost-effective approach for wastewater treatment. However, membrane fouling remains an obstacle to this application. To address this concern, we fabricated an electroconductive membrane composed of polysulfone and polyaniline (PAni). These membranes have the potential to oxidize targeted organic compounds and/or electrostatically remove the fouling layer. After optimizing the PAni loading, we performed bench-scale tests using sodium alginate as model foulant. The membranes were fouled resulting in a decrease in FO efficiency of 72%. Fouled membranes were treated with a cathodic potential for 30 min, the fouling and antifouling processes were monitored with scanning electron microscopy (SEM), and contact angle and electrochemical methods were used. The fouled membrane exhibited a clogged surface and high electrical resistance, while the treated membrane recovered the PAni nanofibers morphology, its electrical and hydrophilic properties, and 84% of its FO efficiency. Thus, PAni can improve the overall membrane permeability while incorporating antifouling properties. Moreover, the EIS results of this study shed light on the mechanisms that govern the water separation process before and after fouling in the FO mode.