Synthesis and flocculation performance of a chitosan-acrylamide-fulvic acid ternary copolymer

The flocculant made from natural polymers gained prominence in recent years due to its eco-friendliness and low cost. In this study, two natural polymers of chitosan and fulvic acid were successfully grafted with a synthetic monomer of acrylamide as a new type of flocculant. The prepared chitosan-acrylamide-fulvic acid (CAMFA) exhibited an excellent capacity to remove three typical dyes, the color removal ratios were 97.0%, 91.6%, and 38.2%, respectively, at the dosage of 283 mg/L for 100 mg/L of acid blue 113, reactive black 5 and methyl orange. The main flocculation mechanisms were charge neutralization and bridging effect. CAMFA showed nice flocculation performance with solubility in pure water, high removal efficiency, broad pH effectiveness scope, and a wide flocculation window. The ternary copolymer based on natural polymers is a promising candidate as a flocculant from the perspective of effectiveness, operation simplicity and cost.