Layered Double Hydroxides/Multiwalled Carbon Nanotubes-Based Composite for High-Temperature CO2 Adsorption

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• 作者：Lakshminarayana Kudinalli Gopalakrishna Bhatta ; Seetharamu Subramanyam ; Madhusoodana D. Chengala ; Umananda Manjunatha Bhatta ; Puspendu Guha ; Raghavendra Prasad Havenje Dinakar ; Krishna Venkatesh
• 刊名：Energy & Fuels
• 出版年：2016
• 出版时间：May 19, 2016
• 年：2016
• 卷：30
• 期：5
• 页码：4244-4250
• 全文大小：456K
• 年卷期：0
• ISSN：1520-5029

文摘

Layered double hydroxides (LDH)-derived mixed metal oxides (MMO) are considered as promising solid sorbents for CO₂ capture in the temperature range of 350–500 °C. Accordingly, they find potential applications in the sorption enhanced water–gas shift process and in removal of CO₂ from hot flue gas/syngas. Numerous strategies have been explored to improve the CO₂ capture property of LDH-derived MMO under the conditions of intended applications. These strategies include novel sorbents by replacement of cations and intercalation of organic anions on Mg–Al LDH, development of LDH-based hybrid/composite materials, optimization of synthesis conditions to control particle size, and method development for different types of alkali impregnation. The present work involves synthesis of a Mg–Al LDH/multiwalled carbon nanotubes (MWNTs) composite and explores its applicability for CO₂ capture under dry conditions. Additionally, K₂CO₃ is impregnated onto the composite to study the effect of alkali promotion. The K₂CO₃-promoted Mg–Al LDH/MWNT composite exhibited a fresh adsorption capacity of 1.12 mmol gp>–1p> at 300 °C under a total pressure of 1 bar. The enhanced CO₂ sorption capacity of composites in comparison with their pristine counterparts can be attributed to improved particle dispersion. Further, the K₂CO₃-promoted Mg–Al LDH/MWNT composite shows an average working capacity of 0.81 mmol gp>–1p> over 10 cycles in the temperature range of 300–400 °C. The deactivation model provides excellent predictions of the experimental CO₂ breakthrough curves obtained with various sorbents. The values of model parameters are comparable with those reported in the literature.