Enhancing fouling resistance of polyethylene anion exchange membranes using carbon nanotubes and iron oxide nanoparticles

Abstract

This work presents the enhancement of organic fouling resistance of nanocomposite anion exchange membranes made from a commercial polyethylene anion exchange membrane and a negative thin layer. This layer is composed of sulfonated poly (2,6-dimethyl-1,4-phenylene oxide) (sPPO) and two nanomaterials of different geometry and composition, oxidized multi-walled carbon nanotubes CNTs-COO− (0.2% g g− 1 to 0.8% g g− 1) or sulfonated iron oxide nanoparticles Fe2O3-SO42 − (0.2% g g− 1 to 0.6% g g− 1). The novel nanocomposite membranes showed a relevant improvement in fouling resistance caused by the modification of some physicochemical characteristics of membrane surface such as charge, roughness and hydrophilicity. The nanocomposite layer did not show a change in the membrane resistance. No remarkable differences were detected when changing the nanomaterial during characterization of nanocomposite membranes. The optimized loading of iron oxide nanoparticles and carbon nanotubes at 0.4% and 0.6% improved membrane fouling resistance by 45% and 53%, respectively. The improved fouling resistance of the best nanocomposite membranes AM-0.6CNTs remained after 12 h of operation. Energy savings between 49% and 60% were also achieved.