Promotional effect of microwave radiation treatment on the desorption of CO2 from mono-ethanolamine (MEA) solution over FeOOH catalyst

Zhang, H. and Lv, J. and Xiong, Z. and Shi, H. and Jin, J. and Liu, M. and Du, Y. and Lu, W. (2024) Promotional effect of microwave radiation treatment on the desorption of CO2 from mono-ethanolamine (MEA) solution over FeOOH catalyst. Journal of Environmental Chemical Engineering, 12 (6): 114382. ISSN 2213-2929

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Abstract

Herein, microwave radiation had been applied to increase the catalytic desorption of CO2 from CO2-loaded MEA solution over the iron hydroxide catalyst, which was found to further accelerate the CO2 desorption rate at the heating stage and decrease the relative desorption heat duty of FeOOH catalyst, and the M-FeOOH catalyst presents a good stability for CO2 desorption. The treatment of microwave radiation leads to the decomposition of partial Fe-OH functional group of iron hydroxide and promotes the lattice transitions from β-FeOOH to α-FeOOH, which decreases the BET surface area and weak acid sites of FeOOH catalyst slightly, but increases the dispersion, medium-strong acid sites and pore volume of catalyst. Furthermore, this treatment reduces the calculated surface molar ratio of lattice hydroxyls/(lattice oxygen + lattice hydroxyls), but the cyclic test helps to the formation of hydroxyl oxygen from the adsorbed water, which plays an important role on the regeneration of MEA solution. The results of DFT calculation indicate that water molecule indeed contributes to converting the original intra-molecular proton transfer into the molecule-to-molecule proton transfer in the reaction of isomerization actively. Finally, the influence of iron-based catalyst on the isomerization of MEA solution are calculated by choosing Fe2+ of ferrous chloride as the unsaturated metal (LAS) active sites to simulate the adsorption of carbamic acid, and found that the adsorption of LAS and uniformly dispersed active sites of iron-based catalyst contributed to providing an advantageous condition for the decomposition of carbamate and promoting the regeneration of MEA.