Global warming and environmental pollution are among the current global issues. Various regulations and measures have been put in place to reduce the overdependence on fossil fuels. However, owing to the underdevelopment of alternative renewable energy sources, the use of fossils fuels cannot be completely eliminated. Therefore, efficient technologies for mitigating global warming and other related effects is highly desirable. As such, researchers have identified low-cost and sustainable carbon dioxide absorbents as a promising solution.
To this note, several carbon dioxide absorbents have been developed. Whereas operating temperature is the main factor considered in the classification of absorbents, efficient intermediate and high-temperature absorbents are still missing. In a recent study, magnesium oxide has demonstrated good carbon dioxide absorbing capability in intermediate temperatures in the range of 200°C to 500°C. Despite the remarkable improvements, a sluggish trend is still witnessed in the absorption of carbon dioxide using magnesium oxide, attributed to high lattice enthalpy. Alternatively, it has been showed that using promotion reagents like alkaline metal nitrates are ideal for overcoming the problem. Also, owing to the poor cyclability of alkali metal nitrates, alkali metal carbonates involving additives have been henceforth identified as good alternatives for promoting magnesium oxide absorption capacity.
Recently, Sungkyunkwan University researchers: Jin-Su Kwak (Ph.D. candidate), Dr. Kang-Yeong Kim, Kyung-Ryul Oh (Ph.D. candidate) and Professor Young-Uk Kwon from the Department of Chemistry conducted an experiment to enhance carbon dioxide absorption of sodium carbonate promoted magnesium oxide absorbents. In addition, the effects of using ZrO2 as the dispersion medium was investigated. ZrO2 with high surface area ZrO2 was chosen due to its chemical stability. The main aim of the study was to enhance the performance of all-solid carbon dioxide absorbents. Furthermore, the cyclability of the developed absorbent and the carbon dioxide absorption were predicted based on the variation of the ZrO2. Their research work is currently published in the journal, International Journal of Greenhouse Gas control.
The team observed that the introduction of the ZrO2 significantly enhanced the conversion and kinetics of the magnesium oxide. In addition, it was necessary to conduct the cycling test repeatedly for both the absorption and desorption processes. Remarkable performance and stability were exhibited by the sodium carbonate promoted magnesium oxide absorbent. For instance, the conversion of magnesium oxide was increased by half.
In summary, the Sungkyunkwan University scientists led by Professor Young-Uk Kwon successfully utilized ZrO2 to enhance the CO2 absorption performance of Na2CO3 promoted MgO. From the analysis of the various carbon dioxide absorption and desorption stages, the homogenous distribution of the MgO and NaCO3 was noted due to the large surface area. This further increased the absorption of CO2. In addition, the durability of the absorbent was greatly increased since no active components aggregated during absorption and desorption. Generally, the importance of a solid dispersant in enhancing the performance of solid absorbents was uncovered.
Kwak, J., Kim, K., Oh, K., & Kwon, Y. (2019). Performance enhancement of all-solid CO2 absorbent based on Na2CO3-promoted MgO by using ZrO2 dispersant. International Journal of Greenhouse Gas Control, 81, 38-43.Go To International Journal of Greenhouse Gas Control