Next-Generation Chitosan Nanocomposites for Water Purification: Mechanisms, Modifications, and Applications

Abstract - The increasing levels of water pollution caused by industrialization, urbanization, and agricultural activities have necessitated the development of efficient, sustainable, and eco-friendly water purification technologies. Among emerging materials, chitosan-based nanocomposites have gained significant attention due to their biodegradability, non-toxicity, cost-effectiveness, and excellent adsorption properties. This review provides a comprehensive overview of next-generation chitosan nanocomposites for water purification, focusing on their synthesis methods, surface modification strategies, mechanisms of pollutant removal, and practical applications.

Chitosan, a natural biopolymer derived from chitin, possesses functional groups such as amino and hydroxyl moieties that facilitate interactions with a wide range of contaminants, including heavy metals, dyes, and organic pollutants. However, its inherent limitations, such as poor mechanical strength and limited stability, have led to the development of advanced nanocomposites incorporating metal nanoparticles, metal oxides, graphene derivatives, and biodegradable polymers. These modifications significantly enhance the structural, mechanical, and adsorption properties of chitosan.

Various synthesis techniques, including ionic gelation, in situ synthesis, sol-gel methods, and green synthesis approaches, have been explored to fabricate efficient nanocomposites. The pollutant removal mechanisms primarily involve adsorption, chelation, electrostatic interactions, ion exchange, and photocatalytic degradation, often working synergistically to achieve high efficiency. Additionally, these materials demonstrate antimicrobial activity, making them suitable for comprehensive water treatment.

The review also highlights the diverse applications of chitosan nanocomposites in removing heavy metals, dyes, and microbial contaminants, along with their regeneration and reusability potential. Despite their advantages, challenges such as scalability, stability, and nanoparticle leaching remain critical concerns. Future research should focus on the development of smart, sustainable, and cost-effective nanocomposites to enable large-scale implementation.

Overall, next-generation chitosan nanocomposites represent a promising solution for addressing global water purification challenges and advancing sustainable environmental remediation technologies.

Keywords: Chitosan nanocomposites; Water purification; Wastewater treatment; Adsorption mechanisms; Surface modification; Green synthesis; Heavy metal removal; Photocatalytic degradation