Chitosan-based adsorbents for analytical sample preparation and removal of pollutants from aqueous media: Progress, challenges and outlook

The development of greener and more efficient materials for extracting environmental contaminants from various matrices is a growing area of research. Materials that do not cause secondary pollution are highly desirable in such applications. Chitosan (CS) is a non-toxic biopolymer enriched with amino and hydroxyl groups, used not only for extracting pollutants but also for crosslinking and functionalizing CS with other materials. The composites of CS with carbon, metal-organic frameworks, metal and metal oxide nanoparticles, and magnetic materials have been used to extract various inorganic and organic analytes in aqueous samples. CS-based sorbents have been evaluated across multiple extraction techniques, such as dispersive solid phase extraction, magnetic solid phase extraction, solid phase microextraction, syringe solid phase extraction, membrane-protected solid phase extraction, and others. This review offers an overview of the CS-based sorbents in analytical extractions, highlighting their strengths, weaknesses, and potential solutions. At the end, a brief overview of the CS-based adsorbents in water treatment applications is also provided.