Investigation of plasma-induced methylene blue degradation using dielectric barrier discharge

Zhao, Y. Y. and Wang, T. and MacGregor, S. J. and Wilson, M. P. and Given, M. J. and Timoshkin, I. V.; (2014) Investigation of plasma-induced methylene blue degradation using dielectric barrier discharge. In: Proceedings of the 20th International Conference on Gas Discharges and their Applications. UNSPECIFIED, FRA, pp. 566-569. (http://gd2014.sciencesconf.org/28567)

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Abstract

Non-thermal plasma can produce reactive species such as O, O3 and OH toinduce dye degradation in water. Many chemical reactions are known to occur at the plasma-water interface, but contributions from each reactive species for the degradation are still not clear. This research investigated the discoloration ofmethylene blue using a specially-configured dielectric barrier discharge reactor, where the plasma was injected into the methylene blue solution through micro-holes to initiate the oxidation reactions at different pH values of 2.9, 7.1 and 11. The degradation effects from hydroxyls and ozone were determined separately by using the radical scavenger Tert-butanol. The results demonstratethat methylene blue is degraded by both ozone and reactive hydroxyl radicals,with the latter contributing up to 30% of the discoloration effect depending onsolution pH values. The yield of plasma-produced hydroxyl radicalsup to 4.6 g/kWh was achieved and the efficiency was not affected by solution pH values; the corresponding methylene blue degradation efficiency is 184 g/kWh.