Synthesis and Characterization of Pan-Based Potassium Silver Iodide Composite Membrane for Industrial Separation Applications

A potassium silver iodide (PSI) nanocomposite embedded within a polyacrylonitrile (PAN) matrix at a 3:1 ratio was successfully engineered using the sol–gel mechanism. The nanocomposite's physicochemical characteristics were meticulously examined through thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and X-ray diffraction (XRD), confirming its composition, functional groups, crystalline nature, thermal stability and surface morphology. The electrochemical behavior of the PSI/PAN membrane, prepared with the most stable polymer composition, was assessed by measuring membrane potential and fixed charge density using various 1:1 strong electrolyte (KCl, NaCl, KNO₃, and NaNO₃) over a concentration range from 1 to 0.001 M. The membrane potential measurements revealed the following order of electrolyte response: NaCl > KCl > NaNO₃ > KNO₃. Based on these observations, the membrane's charge density was determined to evaluate its ion selectivity and separation capabilities. Additionally, the Teorell–Meyer–Sievers (TMS) model was employed to derive key electrochemical parameters, including membrane's charge effectiveness, cation transport number (t⁺), and mobility ratio (ω). NaCl demonstrated the highest values for charge effectiveness, ω, and t⁺, highlighting its superior cation selectivity. Overall, the above parameters well justify the separation performance of the membrane.