Evaluation of flocculation characteristics of kaolinite dispersion system using guar gum: A green flocculant

Abstract

This paper reports the systematic investigation on the flocculation, sedimentation and consolidation characteristics of kaolinite using guar gum as a green flocculant. In-situ flocculation behavior of kaolinite at various pH, guar gum dosages, and ionic strength were studied using a light scattering technique. The effect of these parameters on the settling rate, solid consolidation, and supernatant liquid clarity was recorded. The morphology of kaolinite and flocculated kaolinite aggregates were analyzed using FESEM. The morphology studies suggest that it is poorly crystalline with multiple steps on edge, broken edge; laminar with high aspect ratio and have rough basal surface. The complex irregularity on the basal surface and the presence of multiple steps in the edges, broken edges (hydroxyl groups) have facilitated the guar gum adsorption. The isoelectric point of kaolinite is pH 3.96. The pH, ionic strength and flocculant dosage have a significant effect on the kaolinite settling rate. The guar gum has exhibited excellent turbidity removal efficiency at pH 5. The turbidity removal is inefficient at pH 10. However, guar gum has shown high turbidity removal with 80% transmission at pH 10 in the presence of a KNO3 electrolyte. (C) 2019 Published by Elsevier B.V. on behalf of China University of Mining & Technology.