Steam Plasma Jet Treatment of Phenol in Aqueous Solution at Atmospheric Pressure

Steam plasma jet (SPJ) was generated by phenol aqueous solution introduced into water plasma torch as plasma forming gas, which injected into phenol aqueous solution to conduct oxidation degradation of organic pollutants in aqueous solutions. The experimental results indicated that the phenol was not only decomposed in SPJ, but also degraded in phenol aqueous solution due to high concentration hydroxyl radicals. Moreover, the energy efficiencies significantly increased from (1.6–1.8) × 10−10 to (4.8–8.0) × 10−8 mol · J−1 with the initial concentration of phenol increased from 0.5 to 50.0 g · L−1. The main intermediates of phenol decomposition were pyrocatechol, hydroquinone, maleic acid, butanedioic acid, and muconic acid in liquid. The major gaseous effluence products were H2, CO, and CO2. The steam plasma jet (SPJ) by using phenol aqueous solution as working medium is injected into contaminated water to decompose phenol. Phenol is not only rapidly decomposed in SPJ channel owing to high temperature and high energy electron impact, but also quickly degraded in solution by OH• attack. Meanwhile, generation of a large amount of syngas means the feasibility of this technology for conversion waste to source.