Triethylenetetramine-impregnated ZIF-8 nanoparticles for CO2 adsorption

Abstract

One way to enhance the CO2 adsorption capacity of adsorbents is the incorporation of amines into the structure of the adsorbent. In this study, the impact of impregnation of zeolitic imidazolate framework (ZIF-8) with triethylenetetramine (TETA) over CO2 adsorption was surveyed. ZIF-8 and two TETA-impregnated ZIF-8 samples containing 10 wt% and 15 wt% of TETA were prepared and carefully characterized by Fourier-transform infrared (FTIR), X-ray diffraction (XRD), Thermogravimetric analysis (TGA), N2 adsorption-desorption, and Field emission scanning electron microscope (FESEM) techniques. The CO2 adsorption capacity of prepared adsorbents was examined at various temperatures and pressures using the static volumetric method. Outcomes indicated that at lower pressures than 2.5 bars, the CO2 adsorption capacity of TETA-impregnated ZIF-8 samples was slightly higher than ZIF-8, but by increasing the pressure the ZIF-8 sample showed a higher CO2 adsorption capacity in comparison with TETA-impregnated ZIF-8 samples. Also, CO2 adsorption isotherms of prepared adsorbents were investigated using the Monte Carlo method. Theoretical CO2 adsorption isotherms were similar to experimental ones. Additionally, the CO2 diffusion coefficient in prepared adsorbents was surveyed using molecular dynamics simulation. Results indicated that with the incorporation of TETA molecules in the ZIF-8 structure the diffusion coefficient of CO2 was decreased.