MIXED CO-ZN-AL OXIDES AS ABSORBENTS FOR LAW-TEMPERATURE GAS DESULFURIZATION

High-surface-area zinc-cobalt-aluminium oxides have been prepared hom coprecipitated hydroxycarbonate precursors. The oxides were tested for their H2S uptake in a microreactor at 303 K. The precursors all adopt ed a hydrotalcite-type structure, whilst the oxides were also all sing le-phase materials. Their structures were either based on that of ZnO or Co3O4, which suggested the presence of solid solutions with all the ions dissolved into one phase. A comparison of the H2S uptake of thes e materials with that of the Co-Zn oxides suggested that the presence of aluminium ions in the oxide gave rise to an increase in their surfa ce areas, but that the modified compounds did not absorb significantly more H2S. Indeed, the more Co-rich cobalt-zinc-aluminium oxides absor bed less H2S than Co-Zn oxides prepared in a similar way.