Assessment of feasibility of natural coagulants in turbidity removal and modeling of coagulation process

Abstract

In this research, experiments were carried out in the laboratory to investigate the coagulation/flocculation behavior of natural coagulants, such as chitosan, Moringa oleifera, and cactus mucilage, for the treatment of synthetic turbid water of 314.4-NTU turbidity. A series of experiments were performed with varying the dosage of the coagulants. The result showed that the optimum dosages were 1.5, 80, and 40 mg/l for chitosan, M. oleifera, and cactus, respectively. IR spectral study demonstrates that the functional groups COOH⁻ and OH⁻ were responsible for the coagulation activity. The existence of such functional groups along the chain of charged particles and polygalaturonic acid implies that chemisorption between charged particles and COOH⁻ may occur. The presence of OH⁻ groups along its polymeric chain also infers possible intermolecular interactions which may distort the linearity of the chain. The study clearly indicates that the coagulation activity can be modeled by the Langmuir and Freundlich models. Experimental data fitted very well to both the models, which was proved from the R² values which are almost nearer to unity.

Keywords:

• Coagulation
• Dose
• Turbidity removal
• Modeling
• Chitosan
• Moringa oleifera
• Cactus

Acknowledgments

The authors gratefully acknowledge the financial support and laboratory facilities provided by Mr. Amit Kolhe, Trustee, SRES’s Kopargaon and Dr D. N. Kyatanavar, Principal SRES’s College of Engineering, Kopargaon.