Decolorization of C.I. Reactive Blue 78 dyeing wastewater in the chitosan-gelatin composite copper polymer/sodium persulfate system

Abstract

Chitosan-gelatin composite copper polymer (CG for short) was prepared as an adsorption catalyst. The CG was combined with sodium persulfate to construct a heterogeneous Fenton-like system, which was applied to the decolorization of C.I. Reactive Blue 78 dyeing wastewater. The effects of sodium persulfate, CG, temperature, initial dyeing wastewater pH value and additives ( sodium chloride, sodium carbonate) on the decolorization were investigated. The results show that the decolorization percentage of 0.1g/L C.I. Reactive Blue 78 dyeing wastewater can reach 93.84% under the conditions of sodium persulfate dosage of 0.3g/L, CG dosage of 0.8g/L, decolorization at 40 °C for 30min. At the same time, the catalytic system has the characteristic of good decolorization effect on C.I. Reactive Blue 78 dyeing wastewater within a wide pH values range of 3~9. Even for dyeing wastewater containing 0.4g/L high concentration C.I. Reactive Blue 78, the decolorization percentage can reach over 90% after decolorization at 40 °C for hours. Moreover, CG can be reused. After repeated use of CG four times, the decolorization percentage of C.I. Reactive Blue 78 dyeing waste remains above 90%. In addition, the weight loss rate of CG after each decolorization is less than 12%. However, the presence of sodium chloride and sodium carbonate in the dyeing wastewater is not conducive to the decolorization of C.I. Reactive Blue 78 by the system.