Contributions of Mn-doping in CuO/Al2O3 sorbent for enhancement of H2S removal at low and wide temperature range

In this study, the sorbents of Mn doped CuO loading on alumina particles have been successfully synthesized by hydrothermal method for capturing H2S at low-temperature in a dry and anaerobic environment. Effects of the calcination temperature and Cu/Mn molar ratio on the desulfurization performance of CuO/Al2O3 sorbents are investigated. The low temperature desulfurization performances of CuO/Al2O3 are detected in the fixed-bed reactor and the surface morphologies, phase structures and desulfurization mechanism are systematically characterized using XRF, FESEM, XRD, XPS and HRTEM techniques. It is found that the sorbent prepared under optimum conditions is 300Cu-Mn-(1:1) sorbent and Mn-doping successfully modified the CuO microstructure into fibers. The average breakthrough H2S capacity of 300Cu-Mn-(1:1) sorbent is above 49.7 mg/g from 150 degrees C to 60 degrees C with over 62.3 % CuO active component utilization. Mn doping promotes CuO's breakthrough H2S capacity by 176 %, because the doping of Mn ions may introduce more oxygen vacancies in CuO lattice, resulting to the decrease of the mass-transfer resistance of S ions in the CuO lattice at low temperature. This study provides a reference for low temperature desulfurization during iron production.