Removal efficiency of gaseous benzene using lanthanide-doped mesoporous titania

The adsorptive removal of benzene from cerium- and lanthanum-doped mesoporous TiO2 adsorbents was performed in a continuous-flow, fixed-bed reactor. The influences of lanthanide content and adsorption temperature were investigated. The adsorption efficiency of benzene was remarkably promoted in the presence of lanthanide. The adsorption capacity for benzene increased with lanthanide dosage, which was attributed to the enhancement in a specific surface area. It was determined that 5 mol% rare earth metal was the optimal amount for the highest benzene-adsorption, irrespective of adsorption temperature. Furthermore, the drastic reduction of adsorption capacities at higher temperature implied that benzene molecules were weakly adsorbed to the adsorbents. Additionally, X-ray photoelectron spectroscopy showed a correlation between the adsorption behavior and the chemical properties of mesostructure materials, typically the interaction of surface hydroxyl groups and the pi-electron of benzene, and the formation of sigma-bonding and d-pi* back-donation between the adsorbent and gaseous adsorbate.