Preparation, Characterization and Catalytic Activity for ortho- Dichlorobenzene Ozonation of Fe-, Mn-Doped Xerogels

Metal-doped xerogels were synthesized by the sol-gel method and their catalytic performance was evaluated for the catalytic ozonation of simulated micro-polluted water containing ortho-dichlorobenzene (o-DCB). The obtained samples were characterized by X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), X-ray diffraction (XRD), scanning electron microscopy (SEM), mercury porosimetry and nitrogen adsorption. Results show that Fe3+ oxides and Mn3+ oxides are present in the Fe-doped xerogel (XFe) and the Mn-doped xerogel (XMn), respectively. No obvious diffraction peaks corresponding to a metallic phase were present in the XRD patterns of the xerogels. Also, the metallic particles were found to be small; therefore, the metallic particles were well distributed over the xerogel supports. Catalytic ozonation experiments indicated that the removal rate of o-DCB was 44% with single ozonation, and this increased to 58% and 72% with catalytic ozonation using XFe and XMn, respectively, which suggests that metal-doped xerogels are promising catalysts for the ozonation process. We also investigated metal leaching from the metal-doped xerogel to the water solution to test the stability of the catalysts, and about 2% and 8% metal leaching for XFe and XMn was obtained within 5 h.