Ion-exchangeable and sorptive reinforced membranes for efficient electrochemical removal of heavy metal ions in wastewater

Abstract

This study presents the design, characterization, and application of a novel multifunctional membrane specifically developed for an electrochemical system similar to electrodialysis, with the objective of removing low-concentration copper ions from semiconductor wastewater. The membranes were fabricated using the pore-filling method, where porous polytetrafluoroethylene (PTFE) substrates were impregnated with monomer blend solutions containing vinyl phosphonic acid (VPA) and crosslinking agents, such as polyethyleneglycol dimethacrylate (PEGDMA), acrylated thiourea (ATU), and acrylated tannic acid (ATA), with the ladder two synthesized crosslinkers serving roles as sorptive functionality. These pore-filling membranes exhibited excellent mechanical and dimensional stability, rendering them suitable for application in the electrochemical metal ion sorption system. To evaluate the performance of the fabricated membrane, several key parameters were assessed, including ion exchange capacity (IEC), ionic conductivity (∼110.6 mS/cm), and excellent reusability. Batch-type sorption experiments were conducted to investigate the sorption performance at pH 5 and pH 7, and as a result of applying the membranes to the electrochemical sorption removal system, the membranes demonstrated remarkable efficacy, reducing the copper concentration from 1 ppm to 0.01 ppm. Finally, we confirmed the membrane's ability to remove less than 0.01 ppm of copper even in industrial semiconductor wastewater, validating its practical applicability.