Synthesis of MIL-101(Cr)/graphite oxide composite and enhanced the capacity of methane

Abstract

The aim of this study was to increase the storage density of natural gas for large-scale applications, especially for the storage and transportation of natural gas in remote and scattered small gas fields. The metal organic framework MIL-101(Cr) (Material Institut Lavoisier)/graphene oxide (MIL-101(Cr)/(GO)) composite was studied as a porous material potentially useful for methane storage. First, the MIL-101(Cr)/GO composite was successfully synthesized by hydrothermal synthesis and characterized. The results showed that when the mass fraction of GO reached 15%, the structure of MIL-101(Cr) was damaged, indicating that the material synthesis failed. MIL-101(Cr)/GO composites have higher surface areas and larger pore volumes than MIL-101(Cr). Subsequently, adsorption experiments of methane on MIL-101(Cr) with different mass ratios of GO were carried out. It was found that the MIL-101(Cr)/2.5GO composite had the highest adsorption capacity of methane among MIL-101(Cr)/GO composites, reaching 27.39 mmol/g at 275.15 K and 8.20 MPa. MIL-101(Cr)/GO composites with H2O exhibited gas adsorption and methane hydrate formation resulting in greater methane storage in wet materials than in dry materials. When the mass ratio of water to materials was 1:1, the adsorption-hydration isotherm of methane increased sharply over 3.5 MPa owing to the formation of methane hydrate. The greatest capacity of methane in the MIL-101(Cr)/2.5GO composite at 275.15 K and 8.13 MPa was 33.98 mmol/g, and the storage density was 0.54 g/g, which is much higher than the other materials reported previously. In addition, the MIL-101(Cr)/2.5GO composite for storing methane showed better recycling performance. Compared with pressurized liquefied natural gas and compressed natural gas, the wet MIL-101(Cr)/2.5GO composite for storing methane shows a good economy. These results indicate that MIL-101(Cr)/2.5GO composite may be developed as effective storage material for natural gas storage and transportation.