Degradation of Azo Dye Acid Red 88 by Gas Phase Dielectric Barrier Discharges

Abstract

The degradation of an azo dye, acid red 88 (AR88) in aqueous solutions by a gas-phase dielectric barrier discharge (DBD) system was investigated. The reactive species generated from the DBD system such as OH• radical, ozone and hydrogen peroxide were measured. The effects of various parameters such as gas flow rate, initial pH, input power, initial concentration of AR88 and the gas source on the degradation of AR88 were studied. The results show that OH• radical was the major reactive species generated when 100% relative humidity (RH) air was used. An aqueous solution of 25 mg L−1 AR88 was 96.3% degraded in 5 min treatment, and 68% of the initial total organic carbon was removed in 90 min treatment with 100% RH air at 60 W input power and 7 L min−1 gas flow rate. The degradation kinetics of AR88 followed a pseudo-first-order reaction and was dependent on the input power, gas flow rate, initial AR88 concentration and initial pH.