Optimal condition for modification of chitosan: a biopolymer for coagulation of colloidal particles

Chitosan, an acetylated derivative of chitin, is a biodegradable cationic polymer. Chitosan can be a promising substitute for alum in the coagulation process, because of its potential feasibility in coagulation without posing any health threat as the residual aluminium and other synthetic polymers do. In this study, various pretreatment conditions were tested in search of the optimum chitosan modification. Batch tests with synthetic source water suggest that the optimal pretreatment condition to prepare modified chitosan coagulant is deacetylation by 45% alkali solution for 60 min, followed by dissolution in 0.1% hydrochloric acid.