A MIL-101(Cr) and Graphene Oxide Composite for Methane-Rich Stream Treatment

Composite materials of MIL-101(Cr) and graphene oxide (GO) were synthesized with various concentrations of the two materials using the solvothermal method. The composites were characterized by powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR), and N-2 adsorption-desorption isotherms (Brunnauer, Emmett, and Teller surface area measurement). Methyl mercaptan (MeSH), CO2, and CH4 adsorption capacities of samples were measured using a homemade volumetric apparatus. The results indicated that the hybrid material, which contained similar to 5 wt % graphene oxide, exhibited the highest capacity and reversibility toward MeSH and CO2 sorption. Increases of similar to 12 and similar to 30% in adsorption capacity in comparison to that of pure MIL-101 for CO, and MeSH, respectively, were observed for MIL-101@GO 5 wt %. The MeSH adsorptive capacity on MIL-101 and MIL-101@GO composites was analyzed for the first time in this study, and a high uptake (similar to 32 mmol/g) was obtained. The obtained adsorptive capacity is the highest reported value for MeSH adsorption in the literature and is several times higher than the capacity of traditional mercaptan adsorbents for MeSH adsorption like 13X (3.8 mmol/g). Finally, the CO2/CH4 and MeSH/CH4 selectivities were estimated to be at least 6 and 1102, respectively. This estimation was made according to the ideal adsorbed solution theory based on the single-component gas sorption test data. Because of the high capacity, selectivity, and reversibility of CO, and MeSH adsorption, the MIL-101@GO 5 wt % composite is suggested as a suitable candidate for natural gas and biogas treatment.