水分子对HKUST-1甲烷吸附性能的影响

以三水合硝酸铜和均苯三甲酸为反应物、N,N’-二甲基甲酰胺为溶剂,采用溶剂热法合成金属有机骨架材料HKUST-1。将HKUST-1浸渍于等体积去离子水中,考察浸渍时间对其理化性能的影响,并通过XRD、SEM、BET和高压气体吸附表征研究了水分子对HKUST-1吸附甲烷性能的影响。结果表明,水分子易于吸附在HKUST-1中不饱和金属活性位点且对其骨架结构产生影响,浸渍72 h后,HKUST-1的BET比表面积和孔容分别从1 478.8 m2·g~(-1)和0.700 cm3·g~(-1)降至53.6 m~2·g~(-1)和0.005 cm3·g~(-1),在298 K和3.5 MPa条件下,甲烷吸附量从203.91 cm3·g~(-1)降至13.74 cm3·g~(-1)。但24 h浸渍后的HKUST-1骨架中生成一定数量的介孔,有利于较大的气体或液体分子吸附存储,值得深入研究。

Effects of water molecules on the performance of HKUST-1 for methane adsorption

Using copper nitrate and 1,3,5-benzenetricarboxylic acid as raw materials and N,N’-dimethylformamide as the solvent,a porous metal-organic framework material HKUST-1 was prepared by the solvothermal method.HKUST-1 samples were immersed in the equal volume deionized water,and then the effects of impregnation time on its physicochemical properties were investigated.The effects of water molecules on the performance of HKUST-1 for methane adsorption were studied through the characterization of XRD,SEM,BET and high pressure gas adsorption.The results showed that the water molecules were easy to adsorb on the active sites of unsaturated metal of HKUST-1,which had influence on its framework structure.BET specific surface area and pore volume of the samples decreased from 1 478.8 m²·g^-1 and 0.700 cm³·g^-1 to 53.6 m²·g^-1 and 0.005 cm³·g^-1 after impregnation for 72 h,and the methane adsorption capacity also decreased from 203.91 cm³·g^-1 to 13.74 cm³·g^-1 under the conditions of 298 K and 3.5 MPa.However,the mesoporous structure of the samples emerged after impregnation for 24 h,which might be useful for the adsorption of larger gas molecules or liqiud molecules and was worth making further studies.