Removal of Cu2+ and turbidity from wastewater by mercaptoacetyl chitosan

A macromolecule heavy metal flocculant mercaptoacetyl chitosan (MAC) was prepared by reacting chitosan with mercaptoacetic acid. In preliminary experiments, the flocculation performance of MAC was evaluated by using wastewater containing Cu2+ or/and turbidity. Some factors which affect the removal of Cu2+ and turbidity were also studied. The experimental results showed that: (1) MAC can remove both Cu2+ and turbidity from wastewater. The removal efficiency of Cu2+ by using MAC combined with hydrolyzed polyacrylamide is higher than that by only using MAC, the removal efficiency of Cu2+ reaches above 98%; (2) when water sample containing not only Cu2+ but also turbidity-causing substance, the removal efficiency of both Cu2+ and turbidity will be promoted by the cooperation effect of each other, the residual concentration of Cu2+ reaches below 0.5 mg L−1 and the turbidity reaches below 3 NTU, Cu2+ is more easily removed by MAC when turbidity is higher; (3) the removal efficiency of Cu2+ increases with the increase in pH value, contrarily removal efficiency of turbidity decreases with the increase in pH value.