Chitosan-Based Adsorbents and Catalysts for Removal of Toxic Pollutants from Water and Wastewater

The discharge of industrial, agricultural, and domestic waste into water bodies has raised significant environmental concerns, necessitating effective water treatment techniques. Among the various strategies employed for pollutant removal, adsorption has emerged as a promising approach for the removal of various inorganic and organic pollutants. Chitosan, a biopolymer derived from chitin, has garnered considerable attention for removing a variety of harmful environmental contaminants due to its unique characteristics and active adsorption sites. This review provides a comprehensive analysis of utilizing chitosan-based adsorbents and catalytic materials for mitigation of various emerging contaminants in wastewater treatment. A particular emphasis is given on removing contaminants such as heavy metals, pharmaceutical compounds, organic dyes, phenolic compounds, pesticides, and the photocatalytic degradation of organic pollutants. The study also encompasses various factors influencing adsorption effectiveness, including electrostatic attraction, ion exchange, coordination, complexation, hydrogen bonding, and hydrophobic interactions. In addition, the effect of pH, contact time, initial concentration, and adsorbent dosage on adsorption capacity was also described. Furthermore, this comprehensive study explores the underlying physical and chemical interactions governing pollutant removal for a sustainable water treatment.