“…In this regard, a natural biopolymer is chitosan, which is considered an eco-bioadsorbent, being a complex copolymer of glucosamines and N-acetylglucosamines, thus bearing functional groups that are strongly reactive for different metal ions [5]. The ability of chitosan to chelate metal ions both in solution and solid state has been intensively studied in various polymer forms, such as powder, flakes, microspheres, nanoparticles, gel beads, membranes, sponge, and fibres [6,7]. Chitosan, obtained by deacetylation of chitin, is the most abundant polymer after cellulose, and is a good alternative for the retention of metal ions in wastewater.…”