Arsenic removal approaches: A focus on chitosan biosorption to conserve the water sources

Globally, millions of people have no access to clean drinking water and are either striving for that or oppressed to intake polluted water. Arsenic is considered one of the most hazardous contaminants in water bodies that reaches there due to various natural and anthropogenic activities. Modified chitosan has gained much attention from researchers due to its potential for arsenic removal. This review focuses on the need and potential of chitosan-based biosorbents for arsenic removal from water systems. Chitosan is a low-cost, abundant, biodegradable biopolymer that possesses unique structural aspects and functional sites for the adsorption of contaminants like arsenic species from contaminated water. The chitosan-based biosorbents had also been modified using various techniques to enhance their arsenic removal efficiencies. This article reviews various forms of chitosan and parameters involved in chitosan modification which eventually affect the arsenic removal efficiency of the resultant sorbents. The literature revealed that the modified chitosan-based sorbents could express higher adsorption efficiency compared to those prepared from native chitosan. The sustainability of the chitosan-based sorbents has also been considered in terms of reusability. Finally, some recommendations have been underlined for further improvements in this domain.