Nanoscale Structural Investigation of Cs₂CO₃-Doped MgO Sorbent for CO₂ Capture at Moderate Temperature

Abstract

MgO sorbents doped with alkali-metal carbonates have been shown to exhibit improved sorption capacities at both low and moderate operating temperatures, compared to pure MgO sorbents. However, the mechanism of how alkali-metal carbonates enhance the CO2 sorption is not well understood. Using in situ X-ray diffraction, TEM, and thermogravimetric analysis, we have shown that the cesium dopants in the Cs2CO3-doped MgO nanoparticle system do not simply act as a promoter in sorption of CO2, but rather as a reagent alongside MgO. A new mixed magnesium–cesium carbonate phase has been found to be responsible for the improved sorption capacity of the doped-MgO-based sorbents. On the basis of our findings, it is suggested that a higher sorption capacity may be achieved if cesium is uniformly dispersed throughout the MgO particles.

Controlled morphological structure of magnesium oxide particles

“…In recent years, many experiments regarding magnesium oxide (MgO) based material has been conducted, advantages in distinguish applications of MgO or magnesia has been also discovered [1][2][3][4][5][6]. A great number of applications such as refractory materials [4], catalyst [1,5,[7][8][9], carbon dioxide chemisorbents [6], reflecting and anti-reflecting coating [10], toxic waste remediation [11] and additive to heavy fuel oil [2] utilized MgO powders.…”

“…A great number of applications such as refractory materials [4], catalyst [1,5,[7][8][9], carbon dioxide chemisorbents [6], reflecting and anti-reflecting coating [10], toxic waste remediation [11] and additive to heavy fuel oil [2] utilized MgO powders. These applications requires different characteristic of MgO including the morphology of the particle [12].…”

Structure Transformation of Na-Mg Based Salts for CO2 Capture and Storage at High Temperature Probed with Variable Temperature X-ray Powder Diffraction

“…The high temperature sorbent technology has been studied extensively in order to decrease the CO 2 emission from flue gases of the power plant and industries as a post combustion process [1][2][3][4][5][6]. The system for carbon capture such as membrane, molecular sieves and unique solvents has been devised while these are expected to be high cost and energy demanding.…”

Effect of Syngas Constituents on CdO- and MgO-Based Sorbents for Pre-combustion CO2 Capture

“…It was shown that the sulphur oxide gases readily sorb onto the CO 2 sorbents and degrade the sorbent for further CO 2 sorption due to their strong affinity with the metal oxide sorbent.MgO phase mostly intact, similar to the one observed for carbonation10 .Therefore, this study is concerned with the tolerance of the proposed CdO-NaI and MgO-Cs 2 CO 3 composites towards the syngas constituents hydrogen, water, carbon dioxide and H 2 S. Screening tests by thermogravimetric analysis (TGA) were used to examine the temperature range of the…”

“…sample to H 2 S. The original material contained MgO and a hydrated Cs 2 CO 3 phase if analysed by ex-situ powder XRD after heat treatment6,10 . After H 2 S treatment, MgO is still visible in the pattern.…”