Effect of Cu-Doped ZnO Sorbents for Desulfurization

Abstract

The purpose of this work is to synthesize undoped and Cu-doped ZnO sorbents by citrate-gel method and compare desulfurization efficiency, particularly H2S, at 150°C and 300°C. The undoped ZnO result shows a single phase of hexagonal zincite while the CuO monoclinic phase appeared with ZnO hexagonal phase in Cu-doped compositions (denoted by ZCx where x = mol% of Cu). The microstructure and surface area have been investigated by SEM and BET, respectively. The surface area decreases with the amount of Cu and all of them have a porous structure with small grains. The desulfurization performance of all specimens have been investigated by fixed-bed reactor. The results from breakthrough time indicate ZC20 sorbent has highest sulfur sorption capacity at 300°C. The XRD results show ZnO and CuO in ZC20 can absorb sulfur and completely transform to ZnS, cubic CuS and hexagonal CuS at 300°C.