Preparation, application and regeneration of chitosan composite adsorbents for arsenic removal: A review from a sustainable perspective

Abstract

Chitosan-based composite adsorbents have emerged as critical material for arsenic removal due to their cost-effectiveness and high-efficiency adsorption capabilities for heavy metals/pollutants. This review systematically addresses sustainable strategies for arsenic purification using chitosan composites. Synthesis strategies utilize industrial waste such as shrimp/crab shells and water treatment residues as raw materials, with a critical analysis of preparation methods including homogeneous synthesis and cross-linking polymerization to reduce reliance on traditional chemicals and achieve waste valorization. The adsorption mechanisms of chitosan composites with iron/aluminum and their oxides, such as electrostatic interactions and inner-sphere complexation, are elucidated, highlighting the synergistic effects in efficiently capturing arsenic. Post-adsorption separation and regeneration technologies, particularly alkaline desorption and magnetic separation, are reviewed to enable multiple adsorption cycles, while disposal solutions for end-of-life saturated adsorbents are proposed. Innovatively, a life cycle assessment (LCA) is introduced to evaluate the environmental impacts across the adsorbent's lifecycle, from raw material acquisition to end-of-life disposal, validating the sustainability of the "waste-to-resource" strategy. Future directions explore synergistic composite systems combining chitosan with advanced materials and intelligent platforms integrating point-of-zero-charge (pHpzc) with machine learning. This review provides a comprehensive, sustainability-oriented perspective, offering critical insights to advance chitosan-based adsorbents as sustainable, high-performance solutions for arsenic remediation challenges.

Keywords: Arsenic removal; Chitosan composite adsorbents; Life cycle assessment; Regeneration; Utilization of waste.