Combination of pulsed corona discharge plasma and gamma-Al2O3-supported catalysts for polycyclic aromatic hydrocarbon removal in soil

Removal of polycyclic aromatic hydrocarbon (PAH) in soil by pulsed corona discharge plasma with γ-Al2O3-supported catalysts was studied at normal temperature and atmospheric pressure. Phenanthrene (Phe) was used as the model pollutant. Spontaneous CuO/γ-Al2O3, MnO2/γ-Al2O3, Fe2O3/γ-Al2O3 or TiO2/γ-Al2O3 was added into plasma system. Phe removal, energy efficiency and catalytic property were investigated. The results showed that prepared γ-Al2O3-supported catalysts all exhibited catalytic effects on Phe removal from soil. Removal efficiencies of Phe were improved by 14.1%, 21.4%, 16.5% and 9.1% in 40 min at 5 wt% amount of CuO/γ-Al2O3, MnO2/γ-Al2O3, Fe2O3/γ-Al2O3 and TiO2/γ-Al2O3, respectively. The energy efficiency increased when pulsed corona discharge plasma was combined with catalysts. As each catalyst dosage was increased from 5 wt% to 23 wt%, the energy efficiency of the reactor with discharge alone was further increased by approximately 20%-40%. Furthermore, the catalysts kept stable activity in Phe removal after five times reuse cycle. Effect of pulsed corona discharge plasma on physicochemical properties of catalysts were evaluated through XRD and BET characterization. This study implied a promising combined-application of γ-Al2O3-supported catalysts and pulsed corona discharge plasma for the removal of PAH in soil.