Review on magnetic chitosan nanomaterials as sustainable adsorbents for water pollution control

Adsorption stands out for its simplicity, cost-effectiveness, and high efficiency in removing a wide range of contaminants. However, traditional adsorbents often suffer from limited capacity, selectivity, and reusability. In response to these limitations, a significant research effort has recently focused on developing magnetic chitosan nanomaterials (MCNMs), which combine the inherent biodegradability and biocompatibility of chitosan with magnetic responsiveness for easy separation and reusability. Previous articles reviewed general MCNMs, primarily focusing on their adsorption mechanisms and performance in removing specific pollutants. This review comprehensively discusses recent advances in nanoscale modification of the materials and their applications for enhanced treatment of water containing various heavy metals and pharmaceuticals. A detailed comparison is provided between conventional chitosan materials and their magnetic nano-engineered counterparts (MCNMs), emphasizing improvements in adsorption capacity, kinetics, and regeneration potential. This review also highlights key factors that govern adsorption efficacy, such as pH, surface modification, and pollutant type. By reviewing current trends and challenges in the field, this work aims to guide future research toward the design of more efficient and sustainable water treatment systems, offering a forward-looking perspective on the potential of MCNMs for real-world water and wastewater treatment applications.