Synthesis, characterization and flocculation efficiency of grafted Moringa gum based derivatives

Abstract

This paper reports the synthesis of Moringa gum based flocculants with different monomers using aqueous microwave based method. Moringa was grafted with acrylamide, acrylic acid and an assisted hybrid comonomer (PAM-co-PAA) to develop a comprehensive material suited for all kinds of water quality treatment. Grafting was confirmed by different analytical techniques like intrinsic viscosity measurements, molecular weight, elemental analysis, FE-SEM, XRD, FTIR studies and NMR. All these grafted grades were optimized for best performance at different pH (2-10) and temperature (10-60 °C) range. The flocculation efficiency was tested using coal fine, kaolin and multi-walled carbon nanotube (MWCNTs) suspensions. The efficiency of MOG-g-(PAM-co-PAA) was found to be consistently best as compared to MOG-g-PAM and MOG-g-PAA in all the solutions. This may be due to competitive grafting of PAM with respect to PAA. The treatment with 90% (coal fine), 91% (river water) 92% (kaolin) and 98% (MWCNTs) efficiency was achieved. These results indicate that modified Moringa gum based flocculants can be used for many emerging contaminants in future.

Keywords: Aqueous microwave synthesis; Flocculation; Graft copolymerization; MWCNTs; Moringa gum; Polyacrylamide; Polyacrylic acid.