Abstract:

Aiming at the difficult biodegradation of azo dyes wastewater, comparative experimental study on anaerobic biological decolorization of azo dyes was carried out by comparing the influences of adding different concentrations of electron donors (glucose) and redox mediators (RM) anthraquinone-2, 6-disulphonic acid disodium salt and activated carbon on the anaerobic biological decolorationof azo dyes so as to explore conditions enhancing the anaerobic decoloration of azo dyes. The results indicated that increasing concentrations of the electron donor or the RM can effectively strengthen the anaerobic decolorization of azo dyes wastewater. The decolorization rates up to 53.35%, 34.59% and 35.26% can be achieved with dosage of glucose, anthraquinone-2, 6-disulphonic acid disodium salt and activated carbon for 300 mg/L, 200 mmol/L and 0.6g/L, respectively. When the glucose is added, the decolorization rate is 1.47%/h at 0~24 h, and the decolorization efficiency at 36 h is 46.49%. When the anthraquinone-2, 6-disulphonic acid disodium salt is added, the decolorization rate is 1.03%/h at 0~12 h, and the decolorization efficiency at 60 h is 33.30%. When the activated carbon is added, the decolorization rate is 0.79%/h at 0~30 h, and the decolorization efficiency at 60 h is 33.65%.

Key words: azo dye, anaerobic decoloration, redox mediator, activated carbon, anthraquinone