The impact of hydrolysis process on the performance of polyacrylonitrile membrane in the separation of dye substances

Water scarcity and pollution, driven by rapid industrialization and urbanization, pose critical challenges to global water security. Industrial wastewater, often laden with hazardous dyes, threatens ecosystems and human health due to its toxicity, non-biodegradability, and resistance to conventional treatments. This study addresses these challenges by developing and optimizing polyacrylonitrile (PAN) membranes for dye separation using the nanofiltration (NF) technique. PAN, recognized for its superior chemical stability, mechanical properties, and environmental safety, was fabricated using the Non-Solvent Induced Phase Separation (NIPS) method, followed by alkali hydrolysis for surface modification. The study systematically explores variations in casting solution concentrations (8–14 wt%) and hydrolysis durations (1–3 h) to enhance membrane hydrophilicity, permeability, and selectivity. The optimized membrane, hydrolyzed for 3 h with a 12 wt% PAN solution, achieved a permeation flux of 64.3 L m−2 h−1 bar−1 and a dye rejection efficiency exceeding 99 % for Congo Red. These results highlight the potential of hydrolyzed PAN membranes as a cost-effective and sustainable solution for wastewater treatment, offering a balance between high performance and operational feasibility.