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Adsorption of CO2 on MgAl-CO3 LDHs-Derived Sorbents with 3D Nanoflower-like Structure
- Kou, Xiaochen, Guo, Hongxia, Ayele, Etsegenet Gossa, Li, Shan, Zhao, Yujun, Wang, Shengping, Ma, Xinbin
- Energy & fuels 2018 v.32 no.4 pp. 5313-5320
- adsorption, aluminum, carbon dioxide, desorption, drying, energy, fuels, magnesium, magnesium carbonate, magnesium oxide, methanol, porosity, sodium nitrate, sorbents, surface area, temperature
- In this paper, the porous MgAl-CO₃ LDHs-derived mixed oxides with Mg/Al molar ratios of 2:1, 2.5:1, 3:1, 3.5:1, and 4:1 have been successfully prepared by a facile solvothermal method. With a 3D nanoflower-like structure, the MgAl-CO₃ LDHs-derived mixed oxides with a Mg/Al molar ratio of 2 exhibit the best CO₂ sorption performance of about 0.9 mmol/g at the adsorption temperature of 200 °C. The addition of NaNO₃ into the MgAl-CO₃ LDHs-derived mixed oxides (Mg/Al = 2:1) can facilitate the sorption process by reducing the energy barrier between MgO and MgCO₃. Introducing methanol to the preparation process of LDHs prior to drying can effectively increase the specific surface area and improve the porosity of the sorbents by substituting the water molecules of MgAl-CO₃ LDHs. The sorbents co-modified by NaNO₃ and methanol with a Mg/Al molar ratio of 2 show the favorable sorption performance with the CO₂ uptake of 1.70 mmol/g over 100 sorption/desorption cycles about 300 h.