Research on adsorptive desulfurization of H 2 S from natural gas over Mn x O y -Co x O y supported on activated carbon

Abstract

Mn_xO_y, Co_xO_y, and Mn_xO_y-Co_xO_y supported on activated carbon (AC) adsorbents have been successfully prepared and characterized by specific surface area (BET), X-ray photoelectron spectroscopy, X-ray diffraction analysis, and Fourier-transform infrared spectroscopy. The results show that Mn is present in the form of Mn³⁺ and Mn⁴⁺, and Co is present in the form of Co²⁺ and Co³⁺. For all of the modified samples, the functional groups of the AC were well retained and the specific surface areas followed the order: AC > Mn_xO_y-Co_xO_y/AC > Co₃O₄/AC > Mn_xO_y/AC. For Mn_xO_y-Co_xO_y/AC, Mn and Co mainly exist in the forms of MnO₂, Co₃O₄, and Mn₃Co₂O₈. Mn_xO_y-Co_xO_y/AC was found to exhibit the best H₂S desulfurization performance. At 20℃, the breakthrough time and saturated adsorption time were 115 min and 185 min, and the saturated sulfur capacity and desulfurization rate were 347.7 mg/g and 74.2%. The H₂S removal capacities of the different adsorbents decreased in the order: Mn_xO_y-Co_xO_y/AC > Mn_xO_y/AC > Co_xO_y/AC > AC.