Biowaste-alkaline lignin and GO integrated polysulfone ultrafiltration membrane fabrication for Pb2+ and Eosin Y dye removal

The textile industry uses a variety of lead compounds, including lead acetate for textile dyeing, lead chloride for lead salt manufacture, and lead molybdate for pigments. Furthermore, Eosin Y, a water-soluble red dye, is commonly used in textile dyeing and ink production. The presence of Eosin Y dye and lead metal ions in textile industry effluents is prevalent. Integrating adsorbent nanofillers into the membrane matrix serves a dual purpose of membrane filtration and adsorption functionalities. In this study, Lignin/GO incorporated polysulfone composite membranes were fabricated with the phase inversion method and with PEG 6000 as a pore-forming agent. Zeta potential, pure water flux, mechanical strength, and hydrophilicity of the membranes were all improved by the integration of lignin and GO into the membrane matrix. Filtration operations were carried out using an aqueous solution containing both lead (Pb) and Eosin Y dye. Additionally, the influence of their electrostatic interactions on membrane fouling and the regeneration process was examined. The electrostatic interaction, specifically the linking effect between Pb2+ ions and negatively charged Eosin Y molecules, formed larger Eosin-Pb complexes. This led to an enhanced Pb2+ removal through membrane filtration. During the second filtration cycle, the membrane, comprising 0.75 wt% lignin and 0.75 wt% GO, achieved 100 % removal of Pb2+ ions and an 81 % rejection of Eosin Y. A Pb2+ adsorption study was conducted using the optimized lignin/GO membrane. The adsorption process was investigated through Langmuir and Freundlich isotherms exhibiting a superior fit and assured R2 values of 0.977 and 0.994, respectively. According to the isotherm data the adsorption process involves multilayer physisorption. The developed Lignin/GO-incorporated polysulfone composite membranes hold the promise for tackling issues in a variety of domains, including water treatment and biomedical applications, demonstrating versatility and ability to make positive impacts across industries.