Flocculation of kaolinite suspensions in water by chitosan

Flocculation of kaolinite suspensions in water using chitosan was studied i n the pH range 5-9 and the turbidity ranging from 10 to 160 NTU. Chitosan, in presence of trace quantities of a substance present in aqueous soil extr acts, effectively reduces turbidity due to kaolinite by flocculation and se ttling. Flocculation efficiency is very sensitive to pH. and reaches a maxi mum at pH 7.5. The optimal chitosan concentration required to effect floccu lation is independent of kaolinite concentration within the range examined. Flocculation is faster at higher concentrations of kaolinite and the floes are large and settle rapidly. (C) 2001 Elsevier Science Ltd. All rights re served.