Biodegradable Flocculants Based on Partially Hydrolysed Starch-g-Polyacrylamide

Abstract

Partial hydrolysis of the Starch-g-Polyacrylamide was carried out in alkaline medium. Three grades of partially hydrolysed products were synthesized by varying the reaction parameters. The neutralization equivalent of these products was determined by titrating with standard NaOH solution. Flocculation characteristics of all the hydrolysed graft copolymers were determined in 0.25wt% silica suspension. The partially hydrolysed product with higher neutralization equivalent (Hyd St 3) shows better performance than other partially hydrolysed as well as unhydrolysed products in flocculation. The flocculation performance of Hyd St 3 was also compared with four commercially available flocculants Mag.156, Mag.155, Mag.351 and Rish 440 HV in 5 wt% iron ore and 0.25wt% of silica suspension. The flocculation performance of Hyd St 3 was also compared with Starch-g-polyacrylamide ( St-g-PAM) and Starch in 0.25wt% silica suspension. The results show that the flocculation performance of Starch-g-polyacrylamide is enhanced after partial alkaline hydrolysis and the performance of Hyd St 3 is at per of some commercial flocculants and is also better of some other commercial flocculants.