Preparation and characterization of different polyelectrolyte complexes and their application as flocculants

Abstract

Polyelectrolyte complexes (PEC) from poly(diallyl-dimethylammoniumchloride) PDADMAC and two different polyanions, formed in aqueous solution, were characterized by different methods (zeta-potential, net content, turbidity) and applied as flocculants. The flocculation of clay was investigated by sedimentation measurement as well as by a dynamic method, using a Fibre Optical Flocculation Sensor. The results of both methods showed that the most important advantages of PEC were the high velocity of sedimentation and a very broad range of the optimum flocculation concentration. In spite of the differences in the complex-forming behavior of the two polyanions used, no significant differences between complexes of the same composition but different polyanions are obtained. In contrast, the ratio of anionic to cationic charges is of great importance for the mechanism of flocculation. © Steinkopff Verlag 1998.