Evaluation of adsorption efficiency of activated carbon functionalized with methyl diethanolamine in carbon dioxide gas

Background: Adsorption is a process in which some of the components in the fluid phase, are selectively transferred to the surface of the porous solid particles in the filled bed, which is called the adsorbent. The aim of this study was to examine the adsorption effectiveness of CO2 by activated carbon functionalized with methyl diethanolamine (MDEA), as well as the effects of adsorption temperature, the total pressure of adsorption, and mass of adsorbent. Methods: Activated carbon was first produced using the desired biomasses and suitable activated carbon was chosen. The activated carbon was then functionalized with MDEA amination method. The crystal structure of adsorbents was studied using X-ray diffraction (XRD) methods. In addition, the porosity, specific surface area and structure of prepared activated carbon were measured using BET techniques. Finally, the morphology and strength of the functional groups were measured using Field emission scanning electron microscopy (FESEM) and Fourier-transform infrared spectroscopy (FTIR) analyses. Results: The findings of the FESEM and BET analyses for functionalized activated carbon revealed that the specific surface area of the adsorbent increased throughout the chemical and physical modification process, resulting in a BET amount of 725/84 m2/g. The results showed that the selectivity of the functionalized activated carbon is greater than that of the non-functionalized adsorbent. Conclusion: The adsorption capacity of functionalized activated carbon was 3.98 mmol CO2 g-1 sorbent, compared to 2.587 mmol CO2 g-1 sorbent in the non-functionalized carbon, indicating a 35% improvement in the efficiency of the functionalized sample. According to the findings of the desorption experiments, functionalized carbon shows a 25% decrease in CO2 adsorption efficiency after 20 desorption steps.