A review on the use of chitosan and chitosan derivatives as the bio-adsorbents for the water treatment: Removal of nitrogen-containing pollutants

Chitosan and its derivatives have been widely used as the adsorbents for different types of water pollutants. This review paper lists various physically and chemically modified chitosan-based adsorbents such as chitosan beads, cross-linked chitosan, chitosan-polymer composites, chitosan-inorganic material composites, and chitosan-metal complexes for the removal of nitrogen-containing pollutants (nitrate, nitrite, ammonia, and ammonium ions) from aqueous solutions. It covers preparation strategies, the effect of modification on adsorbent structure, and the impact of adsorption variables using batch and fixed-bed column studies. In addition to demonstrating the applications of chitosan and its derivatives in the removal of nitrogenous pollutants from water, it helps researchers understand the influence of modification of chitosan on its adsorption capacity as well as physical and chemical properties.