Characteristics of natural biopolymers and their derivative as sorbents for chromium adsorption:a review

Chromium is widely used in industry,and improper disposal of wastewater and industrial residues containing excessive chromium can contaminate water and soil,endangering both environmental and human health.Natural biopolymers and their derivatives have been investigated for removal of chromium(Cr)from wastewater.Cellulose,lignin,tannin,chitin,chitosan,and polypeptides are abundant in nature,and have high potential as adsorbents due to their easy access,low cost,and the recyclability of the captured heavy metals.In order to improve their mechanical strength,recyclability,specific surface area,binding site number,and adsorption rate as adsorbents,native materials have also been modified.This review discusses the source of chromium contamination and the main species of interest,as well as their toxicity.The structures of the aforementioned biopolymers were analyzed,and the adsorption mechanism of chromium and the main influencing factors on this process are discussed.The modification methods of various adsorbents and their adsorption effects on chromium are also detailed,and the developmental direction of research on the use of biopolymer adsorption remediation to control chromium contamination is discussed.