Hydrogen sulfide removal from biogas on ZIF-derived nitrogen-doped carbons

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-8derived sorbents, making them promising candidates for H2S removal from biogas.

Automated summary

This study investigated the removal of H2S from biogas using nitrogen-doped carbon materials derived from the carbonization of ZIF-8. The results showed a correlation between H2S sorption capacity and doped N species and porosity, making the sorbents promising candidates for H2S removal from biogas. The H2S sorption capacity was found to be independent of CO2 concentrations, highlighting the potential applications of these materials in biogas purification.