Development of a Cost-Effective Polyamide 6-Based Composite Ceramic Membrane for the Treatment of Cadmium-Contaminated Wastewater

Abstract Cadmium (Cd) is a toxic trace heavy metal commonly found in water bodies, posing a serious environmental threat and reducing water quality. In this study, an innovative and cost-effective polyamide-ceramic composite membrane was developed by dip-coating polyamide-6 (PA6) onto a ceramic support fabricated from natural raw materials, including clay, quartz, feldspar, and starch. The ceramic support was synthesized using a simple and scalable method. Membrane characterization was performed using scanning electron microscopy (SEM), pore size distribution (PSD), and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). The results confirmed the successful formation of a thin and defect-free PA6 selective layer with a reduced pore diameter and improved membrane structure with appropriate functional groups for heavy metal adsorption. The effects of fabrication parameters on porosity, mechanical strength, and water flux were investigated, revealing significant impacts on membrane performance. The performance of both the unmodified and modified membranes was evaluated for the removal of Cd(II) ions from synthetic wastewater. The optimized composite membrane achieved removal efficiencies of 92.00, 97.16, and 98.85% for feed concentrations of 25, 50, and 100 ppm, respectively, with corresponding permeate fluxes of 341.07, 312.30, and 174.64 Lh −1 m −2 , suggesting enhanced performance at higher concentrations, potentially due to increased mass transfer driving force and effective utilization of active sites. Additionally, the modified membrane exhibited favorable antifouling behavior, with a low flux decline ratio of 41% and a high flux recovery of 61%, demonstrating its potential as a practical and sustainable solution for heavy metal removal in wastewater treatment applications.