Effects of sodium persulfate and percarbonate on the degradation of 2,4- dichlorophenol in a dielectric barrier discharge reactor

Abstract

The detection of micropollutants in surface and groundwater bodies has drawn global concern due to their environmental persistence and risk to human and aquatic life. The dielectric barrier discharge (DBD) plasma reactor was employed to degrade the micropollutant 2,4-dichlorophenol (2,4-DCP). The efficiency of the reactor was investigated, and the plasma degradation process was intensified by introducing three eco-friendly oxidants, sodium percarbonate (SPC), sodium persulfate (SPS), and hydrogen peroxide (HPO), into the reactor. Results indicated that 2,4-DCP removal increased from 62.73 % to 76.37 %, 81.93 %, 100 %, and 90.02 % when 1 mM SPC, 1 mM SPS, 3 mM HPO, and 1 mM SPS + 0.33 mM SPC was added to the wastewater solution, respectively. The synergy between the oxidants and the plasma in the DBD reactor was also explored. The largest synergistic factor (1.792) was achieved when 3 mM HPO was added to the DBD reactor, followed by 0.089 for 1 mM SPC, 0.07 for 1 mM SPS, and 0.041 for 1 mM SPS+0.33 mM SPC. The main active species that catalyzed 2,4-DCP degradation were hydroxyl and sulfate radicals, and introducing the oxidants augmented their production in the solution. The synergy between the DBD+SPS+SPC led to a 58.7 % total organic carbon removal. In conclusion, the 2,4-DCP degradation intermediates and mechanisms were deduced accordingly. The findings reaffirm the effectiveness of the oxidant-coupled DBD reactor in the degradation of micropollutants.