(506f) Impregnation of Hydrotalcite with NaNO3 for Enhancement of CO2 Sorption Uptake

It is well known that carbon dioxide (CO₂) emitted from fossil fuel-based energy system has caused global warming. In order to solve this environmental issue, technologies related to hydrogen production as an alternative energy carrier have been suggested. Sorption-enhanced water gas shift (SE-WGS) reaction is one of attractive methods for mass production of hydrogen. In the SE-WGS process, high-temperature CO₂ sorbent is applied and facilitates the production of high-purity hydrogen since CO₂ is a by-product of WGS reaction. Therefore, CO₂ sorbent with high capacity should be developed to improve the efficiency of SE-WGS reaction. Layered double hydroxide, also called as hydrotalcite, has been considered a promising sorbent for CO₂ capture at high-temperature range (200-500 °C). Hydrotalcite typically has fast sorption and desorption kinetics, good thermal stability, and ease of regeneration by pressure or temperature swing adsorption method. However, its low CO₂ sorption capacity should be improved for practical application. Alkali-metal impregnation using K₂CO₃ or Na₂CO₃ is a representative method to increase CO₂ sorption capacity of hydrotalcite. In this study, NaNO₃ was chosen for an alkali-metal precursor and impregnated into hydrotalcite through an incipient wetness method. The structural and textural properties were analyzed using X-ray diffraction and N₂ adsorption analysis, and the effect of NaNO₃ impregnation on CO₂ sorption behavior at high temperature (200-400 °C) was investigated using a thermogravimetric analyzer and in-situ Fourier transformed infrared spectroscopy.