Cross-linked quaternized polyethersulfone-amino crystalline nanocellulose composite membrane for enhanced phosphate removal from wastewater

Cross-linked quaternized polyethersulfone (QPES) hybrid mixed polymer membranes (MPMs) loading amino crystalline nanocellulose (ACNC) were successfully fabricated and applied for phosphate removal. The successful production of novel materials was validated by microscopic, spectral, and microanalytical methods. When compared to the native QPES membrane, the primary qualities of QPES hybrid membranes (hydrophilicity, porosity, permeability, antifouling) have been greatly improved overall. In addition, the surface zeta potential (SZP) and ion exchange capacity (IEC) measurements demonstrated the high positive surface charge densities of MPMs, which is beneficial for phosphate uptake. Phosphate adsorption by these membranes was studied at different temperatures, contact times, and initial phosphate concentrations using batch experiments, to investigate the optimal conditions for phosphate uptake. The MPMs showed excellent adsorption capacities with maximal removal capacities in the range of 68.8–87.95 %. Phosphate adsorption on MPMs was regulated primarily by the Sips isotherm model with multilayer adsorption capabilities and exhibited pseudo-second order kinetics (R2 = 0.9951–0.9976). The positive ΔH° and ΔS° values are indicative of the endothermic nature of phosphate adsorption and randomness increase. The negative ΔG° value indicates the spontaneousity of phosphate adsorption. Phosphate removal effectiveness of the membranes was maintained following recovery and regeneration with NaOH.