Mechanism Research Of Reactive Blue19Wastewater By Electrochemical Oxidation With Pulse

In the textile industry, azo dyes and anthraquione dyes take up the majority of all dyesproducts. The dye wastewaters arising from textile processes, kraft mills, tannery, foods,cosmetic, and other dyeing processes are strongly colored and contain high organicpollutants which show toxicity and carcinogenicity to aquatic life.Colored substances intextile effluents are highly due to incomplete dye fixation on fabric, which about15%-20%of dyes is lost in the dyeing process, included dyeing, fixing and washing processes. Dyewastewater has features of high chroma, complex composition, high concentration oforganic compounds, high toxicity, less-biodegradability, and large variation in quality andquantity, so that it will pollute water environment heavily once emissied directly. Therefore,treatment of dye wastewater has always been a difficult problem for dye industry.The traditional treatment of textile effluents by electrochemical oxidation, used directcurrent as the power supply device. A low-voltage pulse-electrolysis witch overcomes thefatal drawback of high energy cost of the traditional electrochemical method is a newelectrochemical method of wastewater treatment, was developed in this work. Titaniumcoated with mixed metal oxides（Ti/IrO₂-RuO₂-SnO₂）was used for in situ generation ofchlorine in the dye solution. Dyes from the most representative chemical classescommonly used in the textile industry, i.e. azo and anthraquione, were selected. All classesdyes （reaction conditions were100mg/L initial dye concentration,1.5g/L sodium chloride,0.5of duty ratio and15V of applied voltage）showed a good fit of the data to pseudo-firstorder kinetics for color removal, except Disperse Red3B which color removal meet upwith zero-order kinetics. LC-MS and GC-MS were used to identified the intermediatecompounds formed during the degradation and proposed pathways of electrochemicaldegradation of the anthraquinone dye C.I. Reactive Blue19.Compared to a direct current-electrolysis, this pulse-electrolysis cuts the energy cost by65%.