New Vegetal Biopolymeric Flocculant: A Degradation and Flocculation Study

Abstract

Polyacrylamide (PAM) is known to pose a hazard to human health. A newly explored plant-based flocculant, malva nut gum (MNG) is hypothesized to treat water and as a green material. This study investigates the biodegradation, thermal degradation and photodegradation of MNG and its flocculation capability. The results show MNG has a high biodegradation rate and low oxygen consumption rate. MNG biodegraded at Day-17, whilst, PAM did not show completion of biodegradation by the end of the experiment. Thermal degradation analysis shows MNG has a few decomposition stages and ash content. The photodegradation analysis shows photochemical changes in the structure of MNG and PAM. Factorial experiments show pH, concentration of cation and the concentration of MNG were the influential factors in coagulation-flocculation process. Optimization study observed 97% turbidity reduction at pH 5.77, the concentration of cation at 0.05 mM and the concentration of MNG at 0.42 mg/L. Conclusively, MNG operates effectively at near neutral pH and at low concentration. Such results strongly suggest that MNG is a suitable candidate, which could be used to replace PAM, as flocculant in water treatment.