Viscosity of Some Cationic Polyelectrolyte and its Potential Use as Flocculant in Solid/Liquid Separation Processes

Intrinsic viscosities of a cationic polyelectrolyte were determined in salt-free aqueous solution and aqueous/organic solvent mixtures. The investigated polyelectrolyte contains quaternary ammonium salt groups (N, N-dimethyl-2-hydroxypropylenammonium chloride), located along the main chain. In order to obtain the intrinsic viscosities, the experimental data were plotted based on the Wolf method. The results showed that the experimental data fit well with the Wolf model. From the estimated values of the intrinsic viscosities, the dependences of the polyion conformation on the polyelectrolyte concentration as well as on solvent composition were revealed. The flocculating efficiency of this polycation on a model clay suspension was studied by turbidity and zeta potential measurements as well. Moreover, flocs size measurement at the optimum polycation dose was carried out using laser diffraction technology. The results point to simultaneous contributions from both neutralization and patch mechanisms for flocculation process and a unimodal distribution in floc size.