Radiation-induced modification of chitosan and applications for water and wastewater treatment

Chitosan and its derivatives are second abundant polysaccharides in nature, they have been widely applied in different fields because of their wide sources, abundant functional group sites, and various modification strategies. This review summarized recent development of radiation-induced modification of chitosan as well as its application in water treatment. Radiation-induced modification technology can effectively overcome the shortcomings of conventional chemical modification technology, such as large dosage of reagents and uneven modification. Radiation-induced modification can be divided into two types: pre-radiation or mutual radiation, which can achieve functional groups grafting, grafting copolymerization and crosslinking. Various chitosan derivatives synthesized through radiation-induced modification have become efficient functional materials for water and wastewater treatment, such as for adsorption, flocculation and membrane separation. Adsorption is the mostly studied field of their application. Radiation-induced modification can successfully improve the adsorption performances for removal of dyes, metal ions and drugs, which were also discussed in detail. This review will deepen the understanding of the principles and application development of radiation-induced modification of chitosan for water treatment, and provide a reference for the future research.