CO2 fixation mechanism of kaolin treated with organic amines at varied temperatures and pressure

Abstract

CO2 capture and storage is an effective way to control CO2 levels in the atmosphere. However, the adsorption technology is determined by many factors, such as temperature, pressure, and material cost. In this study, a clay-based CO2 adsorbent was designed to monitor the possible factors that affect the geological condensation of CO2 under varied conditions. The effect of molecular chain length on the CO2 adsorption performance of intercalated kaolinite was discussed in detail. The prepared kaolinite/n-hexylamine complex achieved a 17.0 (±0.4) mL/g CO2 adsorption capacity when 6.35% (±0.05) n-hexylamine was loaded, which has significantly improved the utilization rate of organic amines. A higher relative CO2 adsorption capacity (in proportion to the amount of amine) was obtained at lower temperatures and higher pressures. The mechanism of CO2 adsorption of organic amine-intercalated kaolinite was discussed based on Fourier transform infrared spectroscopy and specific surface area measurements. The enhanced relative CO2 adsorption capacity at low-temperature and high-pressure conditions may provide a hint to the geological condensation of CO2 at high latitude positions.