INFLUENCE OF NATURAL AND SYNTHETIC FLOCCULANTS ON THE SEDIMENTATION STABILITY OF SUSPENSIONS

Abstract

Natural flocculants as chitosan and sodium alginate has a complex of environmental and physic-chemical properties: biodegradability, playback of the raw material base, reaction and complexing ability, compatibility with living tissues without toxicity. Researches had shown that chitosan can be used for sorption from aqueous solutions of surfactants, heavy metals and for flocculation of suspensions. The aim of our researches was to study the flocculation ability of the natural and synthetic flocculants. It was studied sedimentation stability of suspensions ground sediments containing macromolecular substances (flocculants) of different nature. As a model system, we used an aqueous suspension of kaolin, in which the surface layer of the particle has a negative charge due to the silanol groups. Kaolin and ground sediments were dried to constant weight at 100° C. The concentration of the dispersed phase in suspensions was 0,3-8,0 %. It was shown that the sedimentation stability defines as flocculants characteristics such as molecular weight, concentration, nature of flocculants, polyelectrolyte’s charge density and nature of the suspensions. It was found that natural flocculants chitosan and sodium alginate are effective synthetic flocculants polyacrylamide type. The findings suggest that the studied natural flocculants have significant potential for use, thanks to a number of advantages: the efficiency of their actions, low reagent consumption, environmental safety.