Evaluation of the efficiency of natural coagulant obtained by ultrafiltration of common bean seed extract in water turbidity removal

Efficiency of natural coagulant obtained by ultrafiltration of common bean ( Phaseolus vulgaris) seed extract in water turbidity removal was experimentally evaluated. Prepared ultrafiltration fractions have shown differences in behavior regarding pH values and dosages at which they expressed their highest efficiency in turbidity removal. The highest obtained coagulation activities were at pH 9.5 with crude extract and fraction containing molecules with molecular weight less than 10 kDa, 50.6% and 49.1%, respectively. The organic load that remained in water after treatment was reduced when natural coagulant processed by ultrafiltration instead of crude extract was applied. Moreover, fraction with molecules between 10 kDa and 30 kDa, decreased chemical oxygen demand by 9% relative to blank at conditions this fraction expressed its highest coagulation activity. (C) 2012 Elsevier B.V. All rights reserved.