Dye wastewater treatment by Chitosan/Bentonite composite flocculant

The flocculation treatment of dye wastewater and practical dyeing wastewater was carried out by chitosan/sodium bentonite composite flocculant,in which the printing wastewater was simulated by eleven kinds of dyes such as Reactive Red X3B.The influence of dosage of composite flocculant,pH,stirring rate and stirring time on flocculant was studied.Results shown when the concentration of dye was 100 mg·L-1,pH was 5,and the dosage of composite flocculant was 1.25 g·L-1,the decolorization for Reactive Red X3B at three mass ratio of composition flocculant were respectively 75%,90% and 97%;The chitosan/ sodium bentonite composition flocculant with mass ratio 1:10 had effective decolorization over 94% on the other eight conventional dyes in the printing and dyeing plant,such as activity,reducibility,dispersion,water-soluble dyes and so on.The removal rate for chroma of wastewater in the printing and dyeing plant before and after treated with A/O were respectively 81.05% and 83.74%,the removal rate for COD were respectively 53.21% and 41.22%.The chitosan/ sodium bentonite composite flocculant will be applied more and more in the future.