In-situ decontamination of heavy metal containing wastewater from oil refineries into catalyst for polycyclic aromatic hydrocarbons hydrogenation coupled with water-gas shift reaction

Abstract

The developing chemical demetallization technologies of petroleum emit thousands of tons of V, Ni, and Fe into water bodies annually for just one oil refinery. For this reason, a metal-containing wastewater (MCW) treatment and reutilization technique is highly demanded to be integrated into petroleum processing. This work introduced an in-situ decontamination of V, Ni, and Fe-containing wastewater from oil refineries into catalytically active particles for polycyclic aromatic hydrocarbons (PAHs) disposal. The water–gas shift reaction (WGSR) was coupled into the reaction system by providing the in-situ H2. In one step, 98.7 wt% of soluble metal ions were precipitated into metal oxides, and 89.6 wt% of anthracene was hydrogenated. It took only 1 h for V, Ni, and Fe ions to crystallize into nanoparticles of V2O3, NiO, and Fe3O4, which could promote both the PAHs hydrogenation and the WGSR. The hydrogenation efficiency via in-situ H2 was 48.7 % higher than that via ex-situ H2. With the increase of PAHs aromatic ring number, the PAHs hydrogenation via in-situ H2 was enhanced. Therefore, this method could simultaneously effectuate the separation of heavy me tals from MCW and the disposal of noxious PAHs in fuel oils.