Preparation of starch-acrylic acid-carboxymethyl cellulose copolymer and its flocculation performance towards methylene blue

Flocculants synthesized from biopolymers show the virtues of low cost, excellent efficiency and environmental friendliness. In this study, starch-acrylic acid-carboxymethyl cellulose (SAC) tertiary anionic copolymers were prepared by graft copolymerization. The optimal synthesis process was determined as raw material ratio of 1:3:1, acrylic acid neutralization degree of 70%, initiator dosage of 1.0 wt%, reaction temperature of 75 degrees C and reaction time of 5 h according to the flocculation performance towards methylene blue simulated waste water. Results demonstrated that the decolorization ratio of methylene blue (100 mg/L) could be up to 81.3% at the SAC dosage of 350 mg/L. The SAC achieved rapid flocculation kinetics and excellent color removal over a broad range of pH, ambient temperature and ionic strength. Furthermore, the operation cost of SAC is only one-fourth of industrial anionic polyacrylamide. The prepared SAC flocculant is promising for industrial dye wastewater treatment owing to its green raw materials, high efficiency and low operation cost.