(656f) Performance Evaluation of Aeea Functionalized ZIF-8 for Direct Air Capture of CO2

Clean air to breathe is a fundamental need for all living creatures. Global environmental issues have arisen as a consequence of the excessive release of greenhouse gases, particularly carbon dioxide (CO₂) pollution [1]. One of the most effective ways to fight climate change and global warming while also encouraging long-term economic growth is not only by capturing CO₂ from source but also from ambient air i.e., Direct Air Capture (DAC) [2]. CO₂ adsorption in the open air is essential for reducing the atmospheric CO₂ concentration and averting global climate change. The structural modification of adsorbents with amine is a new attractive strategy to enhance their CO₂ uptake capacity under low pressure. Zeolitic imidazolate framework-8 (ZIF-8) is renowned for its enormous surface area and remarkable thermal and chemical stability compared to other adsorbents. However, parent ZIF-8 shows relatively low CO₂ capture efficacy. The current work is looking to boost the CO₂ adsorption performance of bare ZIF-8 by functionalizing the porous network of crystalline ZIF-8 nanoparticles using aminoethylethanolamine (AEEA). The CO₂ adsorption behavior of materials was examined using the iSorpHP2 high pressure adsorption equipment under pressure and temperature swing conditions, specifically within the ranges of 0 to 30 bar and 25 to 80 áµ’C. Response surface methodology (RSM) based on the Box-Behnken design (BBD) was exploited to design experiments, develop models, and investigate the optimum conditions for the desirable response i.e. experimental CO₂ adsorption performance, which was affected by temperature, pressure, and amine loading as independent variables. The isosteric heat of adsorption of nascent ZIF-8 and 30% AEEA-grafted ZIF-8 adsorbents is determined between temperatures of 25 and 60 áµ’C using the Van’t Hoff method implemented in the iSorbHP2-Win software. This analysis provides insights into the heterogeneity and surface energy distribution of the materials. Additionally, the CO₂ adsorption was mathematically modeled using numerous isotherm models, based on the regression coefficient (R²) and average absolute deviation (AAD), the Sips model has exhibited outstanding performance in its uptake efficiency to establish a strong correlation between experimental data, surpassing the Toth, Langmuir, and Freundlich models. The CO₂ adsorption capacity (3.56 mmol CO₂/g solid adsorbent) of the prime adsorbent 30% AEEA treated ZIF-8 nanoparticles is highest among the amine incorporated ZIF-8 composite which is 4.5 times higher than that of unmodified ZIF-8 sample (0.862 mmol/g) at 25 áµ’C and 1 bar partial pressure.

References

[1] P. Sardar, G. Bhattacharya, R. Manna, S. Raj, S. Rahut, A. Nath Samanta, Excellent CO2 adsorption performance of amine-impregnated highly porous ZIF-8 adsorbent: Experimental and isotherm modeling studies, Adv. Powder Technol. 35 (2024) 104344. https://doi.org/10.1016/j.apt.2024.104344.

[2] N. Bera, P. Sardar, A.N. Samanta, N. Sarkar, Arginine-Based Ionic Liquid in a Water-DMSO Binary Mixture for Highly Efficient CO2 Capture from Open Air, Energy and Fuels. 38 (2024) 1281–1287. https://doi.org/10.1021/acs.energyfuels.3c03647.