Flocculation performance enhancement of organic polymer flocculants via adjusting cationic block length: Molecular structure and characteristics

Abstract

A development of coagulation-flocculation is to improve flocculation performance of organic polymer flocculants. It is hopefully achieved via optimizing molecular structure of flocculants. Herein, molecular structure of cationic organic polymer flocculants, P(AM-DAC), was regulated through adjusting the length of cationic block on the molecular chain of P(AM-DAC). The effect of block length of P(AM-DAC) on its characteristics, flocculation performances and flocculation mechanisms in water treatment was rarely considered. The moderate template contributed to P(AM-DAC)(10_4:1) possessing the longest cationic block structure, largest molecular weight and best thermal stability compared with other P(AM-DAC). Molecular dynamics (MD) simulation and the flocculation experiments predicted and confirmed that P(AM-DAC)(10_4:1) performed the best in the treatment of colloidal particles and dyes in terms of removal efficiencies and floc characteristics since the centralized cationic block structure enhanced the interaction among P(AM-DAC)(10_4:1) and pollutants and further improved charge neutralization and bridging of P(AM-DAC)(10_4:1).