Removal Of Azo Dye C.I. Reactive Red 195 From Aqueous Solution By High-voltage Discharge Plasma

Our country faces with a double environmental problem of a water shortage and pollution, which has become the important factor to restrict the rapid development of econmy. China is a big dye-producing and dye-consuming country, especially azo dyes are employed in a wide range of processes in textile, paper, leather and plastics industries. Most of azo dyes are highly structured polymers with low biodegradation and of consequence big problems in wastewater remediation. In addition to color in these effluents, many azo dyes are toxic or mutagenic. Dyeing wastewater has been the emphasis and difficulty of industrial wastewater treatment.High-voltage discharge plasma is a new method of water treatment. High-voltage discharge is a blend of physical, chemical, photochemical, ultrasonic and electrical process and the formation of reactive species such as hydroxyl radicals, hydrogen radicals, superoxide radicals, ozone and hydrogen peroxide, etc. Hydroxyl radicals which are highly oxidative, nonselective, and able to decompose many organic compounds. In this paper, we have chosen C.I. Reactive Red 195, as a model contaminant to investigate the degradation mechanism with a needle-plate and high-voltage discharge plasma reactor.The effects of some operating parameters, such as initial pH, intial solution concentration, output power intensity, electrode distance, initial conductivity, air flow rate, something added, were examined. The results are that the degradation efficiency of RR195 increased when initial pH, intial solution concentration, electrode distance and initial conductivity reduced; output power intensity and air flow rate increased. Adding Fe2+and H2O2, the degradation efficiency of RR195 increased. However, if add Fe2+ too much, the degradation efficiency of RR195 reduced. Adding Cu2+, the degradation efficiency of RR195 reduced first, increased later.In the degradation process, the pH of RR195 solution gradually reduced, but the conductivity increased. The removal of solution TOC was 52.51%, after discharging for 21min. Hydrogen peroxide, ozone can be detected in the discharge process. Besides, Cl-, SO42-,NO3- yielded.