Flocculation and Decolorization Effects of Chitosan on Reactive Dye Red M-3BE

The flocculation and decolorization capability of chitosan to Reactive Red M-3BE were discussed,in terms of such factors as the dosage of chitosan,pH,temperature,treatment method,dyeing auxiliaries(sodium sulphate and sodi-um carbonate).The results showed that when 10 mL chitosan solution(4%) was added to the dye solution 100 mL(100 mg/L),the performance of the flocculation and decolorization improved obviously with the decrease of pH value.The decolorization percentage could reach above 90% and the maximum was about 98%.However,the flocculation and decolorization effects of chitosan for the dye worsened sharply with the increase in the concentration of auxiliaries(Na2SO4 and Na2CO3).The wastewater after dyeing was treated with chitosan under fairly good flocculation conditions.Its decolorization percentage and the removal rate of COD were 19.84% and 54.81%,respectively.It was suggested that the reactive dyeing wastewater need to be pretreated with acid to neutralize and desalinate in order to make chitosan achieve better flocculation and decolorization effects.