Modification of Nanofiltration Membranes by Cationic Surfactant as a Promising Strategy for Treatment of Pharmaceutical Wastewater

In this investigation, cationic surfactant cetyltrimethylammonium chloride (CTAC)-modified nanofiltration (NF) membranes were investigated for sodium diclofenac (DFS) removal from aqueous solution. The effects of CTAC incorporation on the membranes at various concentrations below, at, and above the critical micelle concentration (CMC) were evaluated in terms of membrane permeability, morphology, antifouling properties, and performance. CTAC-modified membranes exhibited enhanced structural properties, increased hydrophilicity, higher pure water flux (461 L/m 2 h), and superior antifouling resistance (98% BSA protein rejection, 82.1% FRR). Consequently, the optimized 0.1 wt% CTAC-modified membrane at CMC concentration exhibited superior rejection efficiency compared to the unmodified membrane, increasing from 35.62 to 65.17% for sodium diclofenac removal. The findings of this study demonstrate that the optimized membrane exhibited the best performance in all parameters, making it suitable for practical application in the removal process of sodium diclofenac. Graphical Abstract Highlights Cationic surfactant were used to modify the NF membrane in three concentrations of CMC, above CMC and below CMC. Reactive cationic surfactant was used to improve the anti-fouling and pure water flux performance of membranes. Antifouling performance and hydrophilicity of membranes were enhanced. Drug removal according to membrane surface charge by Donnan's exclusion mechanism.