SUSTAINABLE ADSORBENTS FROM CARBOXYMETHYL CELLULOSE AND CHITOSAN COMPOSITES FOR HEAVY METAL REMOVAL IN WASTEWATER TREATMENT

Abstract

Heavy metal pollution in aquatic systems has emerged as a pressing environmental challenge due to its persistence, bioaccumulation, and toxicity. Among various remediation strategies, adsorption stands out as a simple, efficient, and scalable approach. In recent years, sustainable polymer-based biocomposites have attracted significant attention as alternative adsorbents for heavy metal removal. In particular, carboxymethyl cellulose (CMC) and chitosan (CS) offer unique advantages including biodegradability, environmental friendliness, and a high density of functional groups that enable efficient binding with metal ions. This review provides a comprehensive overview of CMC–chitosan-based composites for wastewater remediation. We summarize their synthesis strategies, structural features, adsorption mechanisms, and reported performances toward diverse heavy metals. Comparative insights with conventional adsorbents highlight the superior adsorption capacity, reusability, and environmental compatibility of these biopolymers. Finally, we discuss the challenges of large-scale implementation, regeneration efficiency, and selective adsorption in multi-ion systems, while outlining future opportunities for advancing green adsorbent design.