Study on preparation of chelating flocculant and its performance of removing cadmium

In this paper, according to the Mannich-Reaction, a kind of chelating flocculant grafted with triethylenetetramine was preparated from polyacrylamide (PAM), formaldehyde and triethylenetetramine. Using this flocculant to remove cadmium from waste water including Cd²⁺ was studied. Due to the chelate functional group grafted on long chain of the PAM, the flocculant is able to capture Cd²⁺ through the flocculating effect and the chelate effect. Obviously, the product can be used to flocculate, subside, and remove cadmium from waste water with low concentration of cadmium. The optimal conditions for synthesizing this flocculant and its usage of removal cadmium were experimented. The results show that the synthetic process of the flocculant is easy to operate, and its capability of removing cadmium is obvious and rapid. For the waste water of 10mg/L cadmium concentration, the above 96% of cadmium was removed from water by adding the flocculant with the ratio of 1:57(V/V). Thus, a novel and low-cost method to remove the deleterious cadmium from waste water is obtained.