Adsorption properties with respect to methane of a functional porous material based on coffee waste

Abstract

A new microporous carbon material (MUM-51) was obtained from waste coffee grounds by carbonization and activation of KOH. MUM-51 has been characterized by various methods, including N2 adsorption-desorption at 77 K, X-ray diffraction analysis, Fourier transform IR spectroscopy, and Raman spectroscopy. Methane adsorption was studied on the resulting adsorbent at pressures up to 10 MPa and temperatures of 298.15, 303.15, 308.15, 313.15, 318.15, and 323.15 K. The specific pore volume of the adsorbent according to DFT is VDFT = 1.604 cm3/g. The BET specific surface is SBET = 3456 m2/g. The maximum value of methane adsorption at a temperature of 298,15 K and a pressure of 10 MPa reaches ~ 19 mmol/g. Experimental data on methane adsorption on MUM-51 were analyzed using the Dubinin–Radushkevich adsorption model in the temperature range 298.15 – 323.15 K and pressures up to 10 MPa. It has been established that the average relative deviations between the experimental results and the results obtained using the Dubinin-Radushkevich model are less than 3%. The initial differential molar heat of methane adsorption on the MUM-51 adsorbent is 28.7 kJ/mol. The results of the work showed that the carbon material obtained from waste coffee grounds, which has a high specific surface area and porosity, can be effectively used as an adsorbent for greenhouse gases, in particular methane.