活性炭/金属有机骨架复合吸附材料的制备及其CH_(4)/N_(2)吸附分离性能研究

Study on preparation of activated carbon/metal-organic frameworks composite adsorbent materials and their CH_(4)/N_(2) adsorption and separation performance

煤层气富含甲烷(CH_(4)),但井下抽采时会混入大量空气导致CH_(4)浓度低、利用难度大,因此富集提浓并高效利用低浓度煤层气的关键是实现CH_(4)与氮气(N_(2))的高效分离。以三水硝酸铜(Cu(NO_(3))_(2)•3H_(2)O)和异烟酸(HINA)为原料,通过逐步合成法制备了活性炭/金属有机骨架(AC/MOFs)复合吸附材料,通过X射线衍射、热重分析和扫描电子显微镜等进行了表征,并研究了气体吸附性能、选择性以及吸附热。结果表明,制备的AC/Cu(INA)_(2)复合材料具有AC和Cu(INA)_(2)的特征衍射峰,并且观察到了Cu(INA)_(2)在AC上的生长。AC/Cu(INA)_(2)复合材料在100 kPa、298 K下的CH_(4)吸附量为12.6 cm^(3)/g,CH_(4)/N_(2)选择性为5.5(比原材料AC提升了17.3%),并且CH_(4)(14.9 kJ/mol)的吸附热高于N_(2)(11.9 kJ/mol)。

Coal bed methane is rich in methane(CH_(4)),but it is mixed with a lot of air during underground mining,resulting in low CH_(4) concentration and difficult utilization.Therefore,the key to enrichment and efficient utilization of low concentrate coal bed methane is efficient separation of CH_(4) and nitrogen(N_(2)).Activated carbon/metal organic frameworks(AC/MOFs)composite adsorbent materials were prepared from copper nitrate trihydrate(Cu(NO_(3))_(2)•3H_(2)O)and isonicotinic acid(HINA)by stepwise synthesis and characterised by X-ray diffraction,thermogravimetric analysis and scanning electron microscopy,and the gas adsorption properties,selectivity and heat of adsorption were investigated.The results show that the prepared AC/Cu(INA)_(2) composite material has characteristic diffraction peaks of AC and Cu(INA)_(2),and Cu(INA)_(2) growth on AC is observed.AC/Cu(INA)_(2) composite material has a CH_(4) adsorption capacity of 12.6 cm^(3)/g at 100 kPa and 298 K,and a CH_(4)/N_(2) selectivity of 5.5(17.3%increase compared to the raw material AC).Additionally,the adsorption heat of CH_(4)(14.9 kJ/mol)is higher than that of N_(2)(11.9 kJ/mol).