Abstract:

Nonthermal plasma processing using a dielectric barrier discharge（DBD）plasma was studied as a method for the degradation of the alizarin red，a kind of anthraquinone dye，dissolved in waterThe effect of several parameters，such as discharging gap，input voltage and the pH values of solution，were investigatedThe results showed that the DBD plasma could degrade the stubborn anthraquinone dye effectivelyIt was found that the concentration of alizarin red solution decreased to 0.26 mg·L^-1 from an initial concentration of 100 mg·L^-1 at the pH value of 84 in 40 min，while the concentration decreased to 1.61 mg·L^-1 at the pH value of 5.8 and 570 mg·L^-1 at the pH value of 7.0 in 45 minIt was also found that the optimum operation condition required a gap of 8 mm and an input voltage of 8 kV，which facilitated generating symmetrical discharging channels，the primary cause of degradation，as well as active speciesThe concentrations of O₃ in the aqueous phase in the presence of buffer solution with different pH values were measuredFurthermore，the experimental results showed that the change of alizarin red concentration was related to the concentration of O₃，an active species with strong oxidation ability，which was important to facilitate the breakdown of organic pollutant.