Iranian Journal of Chemical Engineering (IJChE)

Abstract This study investigates the performance of an electrodialysis metathesis (EDM) process using polyvinyl chloride/carbon nanotube (PVC/MWCNTs) nanocomposite ion-exchange membranes (IEMs) for simultaneous water desalination and chemical production. IEMs, with MWCNTs loadings of 0% (M1), 4% (M2), 8% (M3), and 10% (M4) by weight, were fabricated and characterized for water sorption, areal electrical resistance, hydrophobicity, and mechanical strength. Their ion selectivity, separation performance, desalination efficiency, and production yield were systematically evaluated under varying applied voltages, feed compositions, and operation times. Among the fabricated membranes, M3 (8 wt% MWCNTs) exhibited the best performance, providing optimal ionic conductivity, selectivity, and structural stability. The maximum chemical yield was achieved when the solute concentrations in the electrode chambers exceeded those in the desalination chamber. In contrast, M4 (10 wt% MWCNTs) showed reduced efficiency, attributed to the agglomeration of MWCNTs and pore blockage that hindered ion transport. Increasing voltage improved ion transport to the optimal level, but excessive voltage (15 V) caused water splitting and concentration polarization, lowering both chemical yield and desalination efficiency. These results highlight the importance of optimizing MWCNT loading and controlled operating conditions. Overall, PVC/MWCNT composite IEMs exhibited significant potential for integrated chemical production and the treatment of saline wastewater, providing a cost-effective and scalable strategy for resource recovery.