MgO-based adsorbents for CO2 adsorption: Influence of structural and textural properties on the CO2 adsorption performance

Abstract

A series of MgO-based adsorbents were prepared through solution-combustion synthesis and ball-milling process. The prepared MgO-based powders were characterized using X-ray diffraction, scanning electron microscopy, N physisorption measurements, and employed as potential adsorbents for CO adsorption. The influence of structural and textural properties of these adsorbents over the CO adsorption behaviour was also investigated. The results showed that MgO-based products prepared by solution-combustion and ball-milling processes, were highly porous, fluffy, nanocrystalline structures in nature, which are unique physico-chemical properties that significantly contribute to enhance their CO adsorption. It was found that the MgO synthesized by solution combustion process, using a molar ratio of urea to magnesium nitrate (2:1), and treated by ball-milling during 2.5hr (MgO-BM2.5h), exhibited the maximum COadsorption capacity of 1.611mmol/g at 25°C and 1atm, mainly via chemisorption. The CO adsorption behaviour on the MgO-based adsorbents was correlated to their improved specific surface area, total pore volume, pore size distribution and crystallinity. The reusability of synthesized MgO-BM2.5h was confirmed by five consecutive CO adsorption-desorption times, without any significant loss of performance, that supports the potential of MgO-based adsorbent. The results confirmed that the special features of MgO prepared by solution-combustion and treated by ball-milling during 2.5hr are favorable to be used as effective MgO-based adsorbent in post-combustion CO capture technologies.

Nanostructured MgO Sorbents Derived from Organometallic Magnesium Precursors for Post-combustion CO2 Capture

“…CO 2 capture capacities of these sorbents were in the range of 0.39−1.82 mmol of CO 2 /g, depending upon the different testing conditions. 22,32,35,45,47 Organic magnesium precursors of Mg(Ac) 22,28,32,35,47 The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.energyfuels.8b00866.…”

“…In contrast, the solid-state reaction process could be a facile, economic, and green route for sorbent development. 28,32 Therefore, the direct pyrolysis or calcination of magnesium precursors should be promising for facile preparation of MgO sorbents. The major concern for this method is to determine suitable magnesium precursors.…”

“…Precipitation, hydrothermal, and sol–gel methods have been widely adopted to fabricate highly efficient CO 2 sorbents with improved textural properties and controlled surface morphologies. ,,, However, these synthesis routes will consume massive costly raw materials and chemical additives. In contrast, the solid-state reaction process could be a facile, economic, and green route for sorbent development. , Therefore, the direct pyrolysis or calcination of magnesium precursors should be promising for facile preparation of MgO sorbents. The major concern for this method is to determine suitable magnesium precursors.…”

Morphology Design and Fabrication of Bio-Inspired Nano-MgO–Mg(OH)2 via Vapor Steaming to Enable Bulk CO2 Diffusion and Capture

“…For instance, MgO-based adsorbents for CO 2 capture produced using diverse techniques and under varied circumstances were recently evaluated by Hu et al [1] and Ruhaimi et al [12]. Elvira et al [13] reported 1.61 wt.% of CO 2 capture capacity for MgO sorbent generated by solution-combustion and ball milling at 25 • C. MgO produced using the template approach at 25 • C was examined by Bhagiyalakshmi et al [14], who found roughly 8 wt.%. Ho et al [15] reported 30 wt.% mesoporous MgO produced using the aerogel technique at 30 • C.…”

Understanding CO2 Adsorption on a M1 (M2)-Promoted (Doped) MgO–CaO(100) Surface (M1 = Li, Na, K, and Rb, M2 = Sr): A DFT Theoretical Study

“…There have been studies for enhancing CO 2 capture using porous materials including metal–organic frameworks, hierarchical porous carbon, and ordered micromesoporous carbon nanosphere. − Solid sorbents have a high CO 2 capture capacity. , In addition, solid sorbents absorb CO 2 easily in the capture cycle and CO 2 gas can be released from the absorbent during the regeneration cycle . Solid sorbents, including alkali or alkaline-earth metals, are good materials for CO 2 adsorption owing to their high capture capacities. ,− MgO has advantages as a CO 2 adsorbent by virtue of its low cost, low heat of adsorption, and suitable regeneration temperature of 400–500 °C. ,− Gao et al reported that MgO nanosheets have high specific surface areas and abundant basic sites. However, MgO is thermally unstable during regeneration and has a low sorption capacity compared to CaO .…”