This work studied the H2S removal from biogas, a CO2-containing gas mixture, over nitrogen-doped carbon materials deriving from the carbonization of ZIF-8. The H2S sorption performance on a series of N-doped porous carbon materials was investigated, in which the N-doping composition and textural properties of adsorbents were turned by varying the carbonization temperatures. By changing the carbonization temperatures from 750 to 950 ℃, the N contents vary in the range of 17.75−5.46 wt.%, and the BET surface area in the range of 373-757 cm2/g, while the H2S sorption capacity vary from 28.4–48.2 mg-H2S/g-sorb accordingly. Detailed characterization results (XPS, XRD, FTIR, and TGA/DTA) reveal the correlation of H2S sorption capacity with doped N species and porosity, in which the N surface area/volumetric density is crucial. This observation is corroborated by the kinetic studies by fitting H2S adsorption isotherms with Langmuir and Dubinin-Radushkevich isotherm (DR) isotherms. The H2S sorption capacity is independent of CO2 concentrations examined (up to 40 vol%) on ZIF-8-derived sorbents, making them promising candidates for H2S removal from biogas.
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