Phenol decomposition by gas–liquid phase discharge treatment with different metal electrodes: A comparison study

In recent years, non-thermal plasma technology as an advanced oxidation process has received increasing attention for wastewater treatment . In previous studies, the discussion about the effects caused by different metal electrodes in the plasma treatment system is limited. In this work, phenol degradation efficiency and H 2 O 2 formation with Al, Ti, Fe, Ni, Cu, W, and Mo electrodes were investigated. The use of Fe, Ni, and Al electrodes results in higher phenol removal, than that using W, Cu, Mo, and Ti electrodes. After 70 min of discharge treatment, phenol was continuously decomposed in the solution in the Fe, Cu, and Mo electrodes systems. High peak voltage promoted phenol degradation and H 2 O 2 generation, especially for Fe, Ti and Ni electrodes. The alkaline condition is more conducive to phenol degradation than the neutral and acidic conditions regardless of the electrode type. Fe, Al, Cu, and Ni electrodes are affected more by the adjustment of the conductivity with Cl − than that with SO 4 2− . The dominant influence on H 2 O 2 production and decomposition could be attributed to the catalysis of metal particles and metal ions produced by electrode erosion. According to the radical quenching experiments, the main radicals in the degradation of phenol when using each electrode material were analyzed.