Korean Journal of Chemical Engineering, Vol.39, No.7, 1936-1945, July, 2022
Deep dechlorination of hydrocarbon oil by reactive adsorption on TiO2-based metal oxides
This study reports reactive adsorptive dechlorination of hydrocarbon oil over TiO2-based metal oxides at the temperatures of 20-150 ℃. TiO2 and a series of TiO2-CeO2 were prepared by precipitation method and characterized by N2 adsorption, XRD, FT-IR, pyridine-IR, NH3-TPD and CO2-TPD. The characterization results showed that both the acidity and basicity of the adsorbent had a significant impact on its dechlorination capacity. TiO2-U precipitated by urea exhibited higher dechlorination capacity than TiO2-A precipitated by ammonia due to the higher surface area, more acid and base amounts of the former. Among various Ti(1-x)CexO2 (x=0.1, 0.3, 0.5, 0.7, 0.9, 1) oxides, Ti0.7Ce0.3O2 and Ti0.3Ce0.7O2 bimetallic oxides showed higher dechlorination capacity than TiO2-U, and the chlorine removal over Ti0.7Ce0.3O2 reached 82.8% after adsorption at 150 oC for 3 h. Mixing 5 wt% of alkali earth metal oxide into Ti0.7Ce0.3O2 mechanically enhanced its dechlorination capacity, and the chlorine removal over Ti0.7Ce0.3O2-BaO reached as high as 92.1%. The chlorine removal increased with increasing the adsorption temperature. Ion chromatography and GC-MS analysis revealed that organochlorine compound was converted into Cl and its corresponding alcohol over the adsorbent at 150 ℃. Finally, the mechanism of reactive adsorption dechlorination was proposed.