Application of cationic starch-bentonite composite to adsorb Reactive Red X-3B dye

Since separate use of bentonite or cationic starch in dyeing wastewater treatment results in low color removal and difficult separation of solid from liquid one-step process was adopted and simultaneously the natural bentonite and cationic starch were added into the dyeing wastewater of Reactive Red X-3B,making mutual absorbing of the bentonite and cationic starch so that a cationic starch-bentonite composite clocculant was formed,which had loose structure and greater specific area and absorbed dyes from the wastewater and coducted color removal. An indicator of the percentage of color removal was used to determine the optimal application conditions of cationic starch-bentonite compound through experiments:the dosage of adsorbent was 1. 25 g /L with a mass ratio of 1 ∶ 1,the pH of dyeing wastewater was 7,without additional sodium chloride,and its color removal rate from wastewater of reactive red X-3B was more than 90%. On this basis,the adsorption isothermal line of the cationic starch-bentonite compound was set,which belonged to L-model,and the adsorbent's adsorption of Reactive Red X-3B is coordinated surface adsorption.