Abstract: Chitosan/konjac glucomannan composite flocculant was prepared by modified-crosslinking method. Methylene blue was used as an example to treat printing and dyeing wastewater. The effects of the dosage, adsorption time and pH value of chitosan/konjac glucomannan composite flocculant were investigated by calculating the adsorption rate with reference to literature. The results showed that the initial concentration of methylene blue solution was 8.0 mg/L and the pH of the solution was 9 at room temperature. When the dosage of chitosan/Konjac glucomannan I composite flocculant was 0.3 g, and the adsorption time was 72 h, the adsorption rate of methylene blue solution reached 98.90%.

Key words: printing and dyeing wastewater, chitosan, konjac glucomannan, ultraviolet-visible spectrophotometry