Desulfurization mechanism of an excellent Cu/ZnO sorbent for ultra-deep removal of thiophene in simulated coke oven gas

The reactive adsorption desulfurization mechanism of thiophene over Cu/ZnO sorbent in coke oven gas (COG) was established by a combination of theoretical and experimental study. The adsorption behavior of thiophene on Cu surface was studied by density functional theory (DFT) method. The C4 hydrocarbons releases and sulfur migration over Cu/ZnO sorbent during the thiophene removal process were investigated by comparing with that over CuO, ZnO and CuO+ZnO (prepared by mechanical grinding of CuO and ZnO) sorbents. The results show that the parallel adsorption of thiophene on hexagonal closest packing (HCP) site of Cu (1 1 1) crystal face is the optimal adsorption mode. Cu-0 nanoparticles in Cu/ZnO sorbent have two important roles: (1) adsorb and dissociate H-2, and (2) cleave the C-S bond of thiophene. The sulfur after the cleavage of C-S bond could transfer directly to ZnO and eventually be converted into ZnS without the intermediate product CuS. During thiophene removal, C4H6 and C4H10 are generated over Cu/ZnO sorbent in the presence of H-2. ZnO in Cu/ZnO sorbent not only acts as an excellent sulfur accepter, but can greatly affect the adsorption properties by enhancing the spillover and storage of hydrogen atoms. Increasing the interaction between Cu0 nanoparticles and ZnO to enhance hydrogen spillover is an effective way to improve the thiophene reactive adsorption activity of Cu/ZnO.

Automated summary

The reactive adsorption desulfurization mechanism of thiophene over Cu/ZnO sorbent in coke oven gas (COG) was established by combining theoretical and experimental studies. The study found that Cu-0 nanoparticles in the sorbent play important roles in hydrogen adsorption and dissociation as well as cleaving the C-S bond of thiophene. ZnO in the sorbent acts as an excellent sulfur acceptor and greatly affects the adsorption properties by enhancing the spillover and storage of hydrogen atoms. Enhancing the interaction between Cu0 nanoparticles and ZnO is an effective way to improve the thiophene reactive adsorption activity of Cu/ZnO.