【摘要】应用溶剂热法合成了不同氧化石墨烯(GO)负载量的MOF-505@GO复合材料,分别采用全自动表面积吸附仪、P-XRD、SEM和Raman对材料进行了性能表征,测定了CH4、C2H6和C3H8在MOF-505@GO上的吸附等温线,并进行Langmuir-Freundlich方程拟合,依据IAST理论模型计算了C2H6/CH4和C3H8/CH4二元混合气在MOF-505@5GO上的吸附选择性。研究结果表明,随着GO负载量增大,MOF-505@GO复合材料的孔容及BET比表面积先增大后减小,当GO负载量为5%(质量)时,复合材料MOF-505@5GO的孔容及BET比表面积达到最大,当GO负载量进一步增大至8%(质量)和10%(质量)时,复合材料的孔容及BET比表面积逐渐降低。在0.1 MPa和298 K条件下,MOF-505@5GO对CH4、C2H6和C3H8的吸附容量分别为0.88、4.81和5.17 mmol·g-1,相比MOF-505分别提高了14.9%、30.7%和13.1%。MOF-505@5GO对C2H6/CH4和C3H8/CH4的吸附选择性分别为40.1和3056.1,其对C2H6/CH4和C3H8/CH4具有极高的吸附选择性。
Adsorption isotherms and selectivity of CH4/C2H6/C3H8 on MOF-505@5GO
【Abstract】MOF-505@GO composites with different ratios of MOF-505 to graphite oxide were synthesized by solvothermal method. They were characterized by powder X-ray diffractions (PXRD), scanning electron microscopy (SEM), Raman and porosity measurement through nitrogen adsorption. The isotherms of CH4, C2H6 and C3H8 on the MOF-505@GO and MOF-505 were measured separately. The results show that MOF-505@5 GO has the largest pore volumes and BET surface area. The pore volumes and BET surface areas of MOF-505@GO increase as the GO content increases; when the GO content increases to 8% (mass) and 10% (mass), the opposite trend is observed in which the pore volumes and BET surface areas decrease. Accordingly, MOF-505@5 GO exhibits the highest CH4, C2H6 and C3H8 uptake of 0.88 mmol·g−1, 4.81 mmol·g−1 and 5.17 mmol·g−1 at 298 K and 0.1 MPa, having increases of 14.9%, 30.7% and 13.1%, respectively. Moreover, the IAST-predicted C2H6/CH4 selectivity of MOF-505@5 GO is about 40.1 and the C3H8/CH4 selectivity is about 3 056.1. It suggests that MOF-505@5 GO is a promising candidate for separation of C2H6/CH4 and C3H8/CH4.
【Keywords】 MOF-505@GO; methane; ethane; propane; adsorption; binary mixture;
【Funds】 National Natural Science Foundation of China (21576092, 21276092, 21436005);
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