Characterizations of a functionalized disused plastic-derived membrane and investigation of the effects of process variables on its adsorptive uptake of Pb2+ from simulated effluent using response surface methodology

Abstract

This work focuses on the characterization and performance of the adsorptive membrane produced (via blending) functionalized waste polyethylene water sachets bags (PESWAB) with biopolymers. An adsorptive membrane (5.0 µm pore size) and (2.0 mm thickness) was fabricated from 9.0 g wt composite of PESWAB, chitosan, and cellulose acetate in the corresponding ratios of 1:2:1. Zeta potential, FTIR, SEM/EDX, water contact angle, and TGA/DTA were used to characterize the membrane. Response surface methodology (RSM) was used to model the effects of process variables on the adsorptive uptake of Pb2+ from simulated effluent. The zeta potential was shown to be between −26 and −68 mV at a pH between 4.6 and 9.5. This indicates a good level of stability and adsorptive potential. A hyrophilic membrane was suggested by the low average water contact angle of 79.0°. The gradual decomposition of the membrane indicated that the membrane dope solution was homogeneous. The membrane proved to be a quick and efficient adsorbent for the removal of aqueous Pb2+, as evidenced by the adsorption efficiency (92.0 %) realized at an optimum time of 65 min. The optimization result demonstrated that the RSM predicted and validated removal efficiencies were 96.78 % and 93.95 %, respectively. The regression model's applicability is supported by a low coefficient of variation (0.095 %), a P-value (<0.0001), a high model F-value of 4921.15, and a coefficient of determination (R2) value of 0.9996.

Keywords

• Plastic waste
• Membrane surface modification
• Adsorptive membrane
• Adsorption process optimization
• Lead (II) ion
• Response surface methodology (RSM)