Photo-assisted adsorptive desulfurization of hydrocarbon fuels over TiO2 and Ag/TiO2

Photo-assisted adsorptive desulfurization (ADS) of hydrocarbon fuels using TiO2 and Ag/TiO2 adsorbents under mild conditions has been investigated. UV irradiation (lambda = 365 nm) was directly introduced into the adsorbent packed bed. Typical UV flux at 1 cm from the UV lamp was 1.8-2.0 mW/cm(2). Sulfur removal performance was evaluated by breakthrough experiments in the presence of UV and H2O. Results indicated that the sulfur removal capacity of TiO2 was increased by 50% during UV-assisted ADS. Ag/TiO2 adsorbents showed the highest UV-assisted capacity which was 6.35 mg S/g adsorbent using a model fuel containing 3500 ppmw sulfur (benzothiophene in n-octane) and 1000 ppmw H2O. In situ IR analysis were applied to study the effects of H2O and UV molecules on surface-OH groups. The chemical state change of Ag caused by UV irradiation was characterized by X-ray Photoelectron Spectrometer (XPS). Based on IR data, the enhanced desulfurization capacity of TiO2 under UV irradiation was attributed to the increase in the total number of terminal Ti(IV)-OH groups. Multi-cycle experiments will be carried out later to study the stability of UV-activated sulfur removal sites and the photo-assisted sulfur removal mechanism will be investigated in the future. Published by Elsevier Ltd.