CO₂ Adsorption on Premodified Li/Al Hydrotalcite Impregnated with Polyethylenimine

Abstract

In this study, Li/Al hydrotalcite (HT) was treated with calcination and potassium hydroxyl-ethanol to form bcHT (basic-modified calcined hydrotalcite). This material was then polyethylenimine (PEI)-functionalized to create a new sorbent that has ultralow energy consumption. Various methods were applied to characterize the sorbent, including N2 adsorption–desorption, Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. CO2 adsorption capacity, which was affected by PEI loadings and adsorption temperatures, was assessed with the CO2 adsorption isotherms and cyclic CO2 adsorption–desorption performance. Results showed that the optimal CO2 adsorption capacity of 1.723 mmol/g was reached when operating with temperature of 323 K and PEI loading of 40%. The Freundlich model was applied to provide optimal correlations with the experimental data, and the correlation coefficients reached 0.997. The average isosteric heat of CO2 adsorption was calculated to be 67.492 kJ/mol. The relatively low desorption energy consumption was calculated to be 63.20 kJ/mol with the Amenomiya equation. Four kinetic models were applied to analyze the kinetics of PEI-functionalized bcHT, and both the Avrami’s fractional order model and DEM model were well fitted to the experimental data. The activation energy of the bcHT-PEI-40% was 30.34 kJ/mol calculated by the Avrami’s fractional order model, which is obviously lower than the values of the CO2 adsorption with traditional amine solution.

Study on CO2 Capture Characteristics and Kinetics of Modified Potassium-Based Adsorbents

“…mL/min, the CO2 adsorption capacity of the modified potassium-based adsorbent prepared in this paper reaches 1.5979 mmol/g, which is better than that in the literature [18,23,24].…”

“…It can be seen from the experimental results that under the conditions of reaction temperature is 60 • C, CO 2 concentration is 12.5%, water vapor concentration is 15%, and total gas volume is 550 mL/min, the CO 2 adsorption capacity of the modified potassium-based adsorbent prepared in this paper reaches 1.5979 mmol/g, which is better than that in the literature [18,23,24].…”

Eco-Friendly Fabrication of a Highly Selective Amide-Based Polymer for CO2 Capture

“…Moreover, the enthalpies of adsorption of HCP-MAAMs reported here are 1.82.5 times lower than those of other CO 2 sorbents recently synthesised, such as NUT-10 33 and bcHT-PEI-40%. 38 The smallest was observed for HCP-MAAM-2C in the CO 2 uptake range of 0.15 to 0.55 mmol g -1 , followed by HCP-MAAM-2A in the range of 0.55 to 0.8 mmol g -1 . The lowest displayed by HCP-MAAM-2C was likely due to its lowest CO 2 affinity, due to low porosity of the polymer matrix.…”

“…20,21 Similar results where precursors containing amino group improved the interaction between CO 2 molecules and the pore wall contributed to the improved selectivity have been reported elsewhere. 8,[33][34][38][39][40] The selectivity of HCP-MAAM-2 was found to be 53 at 273 K and dropped to 38 at 298 K. The corresponding purity of CO 2 stream at the two temperatures was 91% and 88% respectively. As the temperature decreases, adsorption capacity increases, while selectivity increases, which is a common adsorption behaviour.…”

K2CO3-Impregnated Al/Si Aerogel Prepared by Ambient Pressure Drying for CO2 Capture: Synthesis, Characterization and Adsorption Characteristics

“…In industrial applications, in addition to a high CO 2 adsorption capacity, the adsorbent should have a fast adsorption rate, which is directly related to the efficiency of the CO 2 capture process. Researchers have conducted in-depth research on the adsorption kinetics of amine-based adsorbents [ 44 , 45 ]. However, there are few studies on the adsorption kinetics of K 2 CO 3 /Al aerogels [ 46 ].…”