Mn-Fe Layered Double Hydroxide Modified Cellulose-Based Membrane for Sustainable Anionic Pollutant Removal

Abstract

This study aimed to investigate the adsorption of As(V), phosphate, and textile dye Acid Green 25 (AG-25) on layered double hydroxides Mn-Fe_LDH and corresponding membranes (wCell/Mn-Fe_LDH). The wCell membrane, derived from waste tobacco boxes, was formed by cross-linking of epoxy and amino modified cellulose fibers with epoxy modified Mn-Fe_LDH and lysine as cross-linker. Structural and morphological analyses were conducted for Mn-Fe_LDH and wCell/Mn-Fe_LDH. The batch system explored pH, contact time, temperature, and initial concentration effects on wCell/Mn-Fe_LDH adsorption efficiency. Adsorption capacities of 82.71, 106.9, and 130.3 mg g−1 were achieved for As(V), phosphate, and AG-25, respectively, indicating effective anionic species removal. Kinetic analysis suggested intraparticle diffusion as the rate-limiting step. Thermodynamic parameters and ionic strength effects indicated a physisorption mechanism for AG-25 and surface complexation for As(V) and phosphate. Biodegradation experiments after five adsorption/desorption cycles revealed the membrane’s decomposition, with phosphate’s strong bonding releasing essential elements valuable for soil fertilization. Effluent wastewater treatment demonstrated low environmental impact through the formation of insoluble As(V) salts and photocatalytic dye degradation.