Adsorption of thiophene and dibenzothiophene on highly dispersed Cu/ZrO2 adsorbents

Abstract

The effect of surface area of copper/zirconia adsorbents on the adsorption of thiophene (T) and dibenzothiophene (DBT) was studied. Adsorbents were prepared with different loads of copper (1–6%), using as support zirconias with different surface areas, obtained by varying the calcination temperature. Lower calcination temperatures allowed obtaining zirconias with higher surface area, but lower crystallinity. The characterization results showed that high surface area zirconias have greater copper dispersion capacity, being the zirconia calcined at the lower temperature, the only able to completely disperse a load of 6% Cu, i.e., Z-300 surface has only highly dispersed copper species, while zirconias with higher calcination temperature have also bulk CuO species. The adsorption capacity of T or DBT on Cu/ZrO2 increased with copper content, reaching a maximum, which coincides remarkably with the zirconia dispersion capacity. This result indicates that dispersed copper species, in Cu1+ state, are responsible for the adsorption of these sulfur organic compounds. Therefore the best adsorption capacities were obtained in adsorbents with high content of such copper species, and these adsorbent can be prepared with high surface area ZrO2, that is with high dispersion capacity of copper.