Experimental study on the performance of modified flocculant (PEI-T) for removal of turbidity and heavy metals from aqueous solution

The current study was focused on the evaluation of the performance of a modified flocculant (PEI-T) for the removal of turbidity and heavy metals from wastewater. Thioglycolic acid was introduced into the molecular chain of cationic flocculant polyethyleneimine (PEI) through an amidation reaction to form a new flocculant PEI-T. Results revealed that: (a) PEI-T and PEI had similar turbidity removal effect, but PEI-T had a good function of catching heavy metal copper and mercury; (b) when Cu2+ and turbidity-causing substances coexist in a water sample, Cu2+ and turbidity-causing substances promote the removal of each other and the residual concentration of Cu2+ and turbidity decrease further; and (c) the presence of Ca2+ and Mg2+ can promote the removal of copper ions by PEI-T. HIGHLIGHTS Modified flocculant (PEI-T) was evaluated for removal of turbidity and heavy metals from wastewater.; Thioglycolic acid was introduced into the molecular chain of cationic flocculant polyethyleneimine (PEI) to form a new flocculant, PEI-T.; These flocculants had similar turbidity removal effect.; Cu2+ and turbidity-causing substances promote their removal when Cu2+ and turbidity-causing substances coexist.;