Fabrication, characterization and electrochemical analysis of a polyvinylidene fluoride plus zeolite embedded manganese phosphate composite ion exchange membrane

Abstract

Nanocomposite ion exchange membranes have significant potential in water purification, especially in desalination. In this study, a novel polyvinylidene fluoride and zeolite nanocomposite membrane, embedded with manganese phosphate (PVDF+Ze@MP), was prepared via the sol–gel method. This membrane demonstrated excellent ion exchange properties, and thermal, mechanical, and chemical stability. It showed resilience in both acidic and basic environments, with no visible degradation, and maintained a thickness of 0.085 cm and a water uptake of 0.070%. The structural configuration of PVDF+Ze@MP was ascertained by SEM, XRD, and FTIR, whereas the thermal properties were examined using TGA analysis. Electrochemical analysis, based on the Teorell–Meyer–Sievers (TMS) model, revealed that charge density significantly influenced ion transport and separation efficiency. The membrane exhibited high cation selectivity, with the membrane potential increasing as the electrolyte concentration decreased, indicating its ability to selectively transport specific ions. Additionally, performance metrics for mobility ratio, transport number, and membrane potential followed the trend KHCO₃ < NaHCO₃ < KCl < NaCl except for fixed charge density, which followed the reverse order highlighting the membrane's adaptability for efficient ion separation. The novelty of this work lies in the synergistic integration of PVDF, zeolites, and manganese phosphate to create a composite membrane with enhanced stability and selective ion exchange performance, making it a strong candidate for challenging water treatment applications. With superior electrochemical properties, low fouling behavior, and robust thermal and mechanical stability, this membrane holds strong potential for practical implementation in desalination and ion exchange processes.