Facile and fast, one pot microwave synthesis of metal organic framework copper terephthalate and study CO2 and CH4 adsorption on it

Copper terephthalate, metal organic framework (MOF) [Cu(BDC)] (H2BDC = benzene-1,4-di-carboxylic acid) was synthesized by simple and fast microwave method. Different samples were synthesized by modifying the irradiation time, irradiation power and concentrations of reactants. The samples were characterized by means of FT-IR analysis, X-ray diffraction (XRD), N2 adsorption/desorption isotherms, scanning electron microscopy, elemental analysis and thermo gravimetric analysis. The effect of synthesis conditions on crystallinity, crystal size, specific surface area and morphology of the prepared samples were investigated. The XRD patterns of all synthesized samples confirmed the formation of Cu(BDC) without any phase impurities. The samples with the highest Langmuir surface area of 624 and 611 m2/g were considered for CO2 and CH4 adsorption isotherms. Adsorption isotherms of CH4 and CO2 were determined by volumetric method in the range of 0.1–60 bar pressure at normal temperature. The highest adsorption capacity for CO2 and CH4 was determined 10.4 and 5.2 mmol/g, respectively at 303.15 K and 47.7 bar equilibrium pressure. The highest selectivity of CO2 by the synthesized MOF was calculated sixfold over CH4 adsorption around normal pressure and the results have shown the capability of the synthesized Cu(BDC) for separation of CO2 from natural gas at low pressures.