Synthesis, characterization and flocculation performance of a novel sodium alginate-based flocculant

In this study, a natural polymer-based organic flocculant (sodium alginate-methacrylatoethyl trimethyl ammonium chloride, SA-PDMC) was synthesized by graft copolymerization. The optimum preparation procedures were determined by single factor experiments. The flocculation behaviors of SA-PDMC were investigated in humic acid (HA) and kaolin suspension considering the effects of flocculant doses and initial pH. The results indicated that charge neutralization and bridging action played an important role in the removals of HA and kaolin. Also, SA-PDMC performed well in a wide pH range of 5.0−10.0. Besides, SA-PDMC, as polyaluminium (PAC) aid, was investigated in the lake water treatment. The ratio of PAC and SA-PDMC was optimized through response surface methodology based on a central composite design. Results showed that SA-PDMC and PAC have a strong synergy, under optimal conditions SA-PDMC can reduce the dose of PAC by 40 % while ensuring the water quality.