The separation of kreutzonit particles by cationic pullulan derivatives from model suspension

Abstract

In the present work the flocculation properties of some cationic derivatives based on pullulan have been tested in a synthetic suspension of zirconium silicate (kreutzonit). The flocculants contain either quaternary ammonium salt groups (grafted chains, poly[(3-acrylamidopropyl)-trimethylammonium chloride] onto the pullulan (P-g-pAPTAC)) or tertiary amine groups (3-dimethylamino-1-propylamine-pullulan) (DMAPAX-P). The impact of polymer dose, the charge content and type (tertiary amine or quaternary ammonium salt groups), the grafted chains length and the suspension pH on the flocculation efficiency have been taken into consideration. The separation of mixtures consisting of kreutzonit, K-feldspar, kaolin, hematite (Fe2O3) particles by some of the above mentioned cationic derivatives was also followed. The addition of different doses of pullulan derivatives to kreutzonit dispersion as well as to particles mixture led to the increase of particles removal efficiency up to 95–99% in the optimum dose intervals. The charge patch and bridging mechanisms played an important role in the flocculation process, as revealed by zeta potential measurements. Flocs resulting from the flocculation process have been used successfully in removal of fungicide Bordeaux mixture particles from synthetic wastewater; a removal efficiency higher than 95% has been found for the optimum amount of flocs (10 g flocs per liter of fungicide suspension).

Keywords

• Pullulan derivatives
• Kreutzonit
• Flocculation mechanism
• UV-Vis spectroscopy
• Zeta potential