A sustainable solution for environmental purification: A review of high-performance hydrogels based on chitosan

As the industrialization process accelerates, environmental pollution issues are becoming increasingly severe, especially water pollution, which poses a serious threat to the ecosystem and human health. Pollutants in water bodies that are difficult to degrade not only exert toxicity to aquatic life but may also accumulate through the food chain, affecting human health. Therefore, the development of efficient and environmentally friendly pollutant treatment technologies has become a popular topic in the field of environmental science. Chitosan (CS), as a natural polysaccharide, is considered an ideal choice for preparing environmentally friendly green materials due to its excellent compatibility, and rich functional groups. CS-based hydrogels, with their unique three-dimensional network structure, high specific surface area, and good hydrophilicity, show great potential in environmental purification. This review aims to systematically summarize and analyze the latest research progress of high-performance chitosan-based hydrogels (HPCSHs) in the field of environment, exploring their performance characteristics, enhancement strategies, and sustainability. Firstly, the structure and characteristics of HPCSHs are introduced, with an emphasis on their adsorptivity, degradability, reusability, environmental responsiveness, biocompatibility, and multifunctionality. Subsequently, four enhancement strategies for hydrogel performance are discussed in detail, including crosslinking modification, surface functionalization, nanomaterials composite, and structure regulation. Then, the environmental impact and sustainability of HPCSHs are assessed. Finally, the current challenges and future development trends are explored. This review provides references and guidance for the research of HPCSHs in the environmental field, offering new solutions for environmental pollution issues.