Efficient cationic flocculant MHCS-g-P(AM-DAC) synthesized by UV-induced polymerization for algae removal.

Graphical abstract Highlights • A functionalized chitosan-based flocculant (MHCS-g-P(AM-DAC)) is synthesized by UV initiation. • The concentration of algae decreased as the flocculants dosage increased. • The removal efficiency of MHCS-g-P(AM-DAC) was higher than that of commercially available coagulant. • MHCS-g-P(AM-DAC) has high efficiency in the removal of algae and turbidity from raw water. Abstract The graft copolymer flocculant of chitosan namely, maleoyl chitosan-graft-poly(acrylamide–acryloxyethyl trimethyl ammonium chloride) [MHCS-g-P(AM-DAC)], was prepared by UV initiation to improve the solubility and flocculation efficiency of chitosan. Flocculating properties for algae removal were studied systematically. The effects of parameters such as monomer concentration, MHCS content, illumination time, photoinitiator concentration, cationic degree, pH and grafting efficiency over synthesis process of MHCS-g-P(AM-DAC) were studied. The characterization of obtained MHCS-g-P(AM-DAC) were carried out through different analytic techniques. The influences of dosage, pH, and G value on the flocculating properties were also investigated to support that MHCS-g-P(AM-DAC) was more effective than organic flocculant (CPAM) and inorganic coagulant (PFS and PAC) on algae removal. The flocculation mechanisms of MHCS-g-P(AM-DAC) were determinate by obtained zeta values. [ABSTRACT FROM AUTHOR]