SYNTHESIS AND CHARACTERISATION OF FLUORINE-FREE MIL-100(Fe) FOR HYDROGEN, CARBON DIOXIDE AND WATER VAPOR STORAGE

Metal-organic frameworks due to their extremely large surface area and pore volume, and tunable surface features, can be considered competitive solutions for gas storage applications, e.g. hydrogen, carbon dioxide and water vapor. In this study, MIL-100(Fe) was synthesized though a HF-free hydrothermal route in a Teflon-lined autoclave at 160 °C for 12h using Iron Nitrate Nonahydrates as precursors. MIL-100(Fe) is composed of a trimeric iron coordinated by a benzene -1,3,5- tricarboxylic linker. The storage capacities towards hydrogen, carbon dioxide, and water vapor have been investigated. The excess gravimetric capacity for hydrogen and carbon dioxide were quantified by a High-pressure volumetric gas sorption analyzer (isorb). Water vapor adsorption is measured by Dynamic vapor sorption DVS analysis. The sample was characterized by powder X-ray diffraction (XRD), N2 adsorption-desorption isotherms and FT-IR analysis. XRD and FTIR data showed an agreement with literature data [1] , thus confirming the synthesis production of the desired MOF. The Nitrogen adsorption isotherms show that MIL-100(Fe) MOF has a BET surface area of 1199 𝑚2/𝑔. The hydrogen adsorption in MIL-100(Fe) MOF is dominated by weak Van der Waal forces. As reference, hydrogen excess gravimetric capacity at 278K and 40 bar is 0.25 wt%. Adsorption- desorption isotherms of carbon dioxide showed a reversibility of the physisorption process. MIL-100(Fe) can store 32.64 wt% at 278 K and 10 bar and this value decreased to 23.86 at 303K and 10 bar. Similarly, the material showed promising water vapor sorption/desorption capacity. These preliminary results make the MIL-100(Fe) an interesting candidate for gas sorption applications. Further studies are ongoing for better assessing the materials storage capacity in different conditions.