Utilization of tertiary amine solutions and ultrasound irradiation for CO2 desorption at low temperature in a CCS process

Abstract

This study used three tertiary amine solutions as a CO₂ absorbent. Ultrasound can desorb CO₂ from CO₂(aq) and H₂CO₃ species at low temperature. Tertiary amine solution with lower pKa created CO₂ adsorption equilibrium at lower pH related to a higher CO₂ desorption amount using 28 kHz ultrasound because the lower pH environment would increase the existence ratio of CO₂(aq). Triethanolamine (TEA) with lowest pKa (7.85) showed the highest CO₂ desorption ratio of 48% for 30 min irradiation at 25 °C. The CO₂ absorption–desorption capacity of TEA by reuse was evaluated and found to keep the first capacity for three cycles.