Synthesizing polyethersulphone membranes with hybrid iron/nickel nanoparticles for dyes removal: An efficient biogenesis approach

Abstract

Industrial wastewater contamination by azo dyes poses a significant environmental challenge. This study reports the green synthesis of bimetallic iron/nickel (Fe/Ni) nanoparticles using moringa leaf extract, which acted as both a reducing and capping agent, and their incorporation into polyethersulphone (PES) membranes to produce eco-friendly nanocomposite membranes for dye removal. The green-synthesized Fe/Ni nanoparticles exhibited uniform morphology and surface functional groups from moringa extract that promoted interaction with dye molecules. Embedding Fe/Ni nanoparticles into the PES matrix enhanced membrane properties, including hydrophilicity, surface smoothness, porosity, and pore size distribution. Among the tested compositions, membranes with 0.7 wt.% Fe/Ni nanoparticles achieved the optimal balance between water permeability and structural stability, with pure water fluxes of 84 and 86 L/m² · h for Naphthol Blue Black (NBB) and Congo Red (CR), respectively, compared to 58 and 54 L/m² · h for the unmodified PES membrane. Dye rejection improved from 81% to 93.2% for NBB and from 83% to 93% for CR, while antifouling performance and flux recovery were also enhanced. The functional groups introduced by moringa extract contributed to adsorption, hydrogen bonding, and van der Waals interactions with dye molecules, supporting reversible fouling and improved separation efficiency. These findings highlight the potential of natural plant extracts for synthesizing bimetallic nanoparticles and producing functional PES membranes with superior wastewater treatment performance. The developed membranes offer a sustainable, environmentally friendly solution for removing hazardous dyes from industrial effluents, demonstrating promise for large-scale water remediation applications.