Deep dechlorination of hydrocarbon oil by reactive adsorption on TiO2-based metal oxides

This study reports reactive adsorptive dechlorination of hydrocarbon oil over TiO 2 -based metal oxides at the temperatures of 20–150 °C. TiO 2 and a series of TiO 2 -CeO 2 were prepared by precipitation method and characterized by N 2 adsorption, XRD, FT-IR, pyridine-IR, NH 3 -TPD and CO 2 -TPD. The characterization results showed that both the acidity and basicity of the adsorbent had a significant impact on its dechlorination capacity. TiO 2 -U precipitated by urea exhibited higher dechlorination capacity than TiO 2 -A precipitated by ammonia due to the higher surface area, more acid and base amounts of the former. Among various Ti (1− x ) Ce x O 2 (x=0.1, 0.3, 0.5, 0.7, 0.9, 1) oxides, Ti 0.7 Ce 0.3 O 2 and Ti 0.3 Ce 0.7 O 2 bimetallic oxides showed higher dechlorination capacity than TiO 2 -U, and the chlorine removal over Ti 0.7 Ce 0.3 O 2 reached 82.8% after adsorption at 150 °C for 3 h. Mixing 5 wt% of alkali earth metal oxide into Ti 0.7 Ce 0.3 O 2 mechanically enhanced its dechlorination capacity, and the chlorine removal over Ti 0.7 Ce 0.3 O 2 -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 °C. Finally, the mechanism of reactive adsorption dechlorination was proposed.