Boosting water flux and dye removal: Advanced composite membranes incorporating functionalized AC-PAA for wastewater treatment

Abstract

This study addresses the challenge of enhancing dye removal and antifouling properties in wastewater treatment by developing a composite membrane incorporating poly(acrylic acid)-functionalized activated carbon (AC-PAA) into a polyethersulfone (PES) matrix. The activated carbon was functionalized using surface-initiated atom transfer radical polymerization (SI-ATRP), followed by hydrolysis to introduce hydrophilic poly(acrylic acid) chains. The AC-PAA composite was characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy, and energy-dispersive X-ray analysis, confirming successful grafting and functionalization. Compared to pristine PES, the addition of 0.5 wt% AC-PAA led to significantly enhanced water flux (54 L/m²h vs. 30 L/m²h) and superior dye removal, achieving 63 % for methyl orange and 67 % for methylene blue at alkaline pH. Poly(acrylic acid) was selected for its carboxyl groups, which enhance adsorption capacity and antifouling characteristics. In addition to effective dye removal, the composite membranes were antifouling, with a flux recovery ratio of 72 %. Response surface methodology optimized parameters, confirming highest performance at pH 11 and 6 bar. AC-PAA functionalized membranes are an efficient solution in wastewater treatment, increasing dye removal and antifouling capacity versus current membrane technologies.