Boosting CO2 absorption and desorption of biphasic solvent by nanoparticles for efficient carbon dioxide capture

Introduction of nanoparticles (NPs) in the solvent was treated an efficient route to enhance mass and heat transfer, therefore, it was a promising strategy to boost carbon dioxide (CO2) absorption and desorption, especially for the biphasic solvent with weak absorption rate and low heat capacity. Herein, powder TiO2 and SiO2 with nanoscale was selected to prepare nanofluid for CO2 capture, based on DMPA-NHD biphasic solvent. The stability of nanofluid and the effect of NPs on CO2 absorption–desorption, phase-splitting was comprehensively explored in this work. Experimental results revealed that 0.06 wt% dosage of 30 nm TiO2 presented excellent performance for CO2 absorption. The liquid film resistance decreased by 11.8% after introducing NPs, therefore, the maximum mass transfer coefficient was 1.88 × 10-10 mol·cm−2·s−1·Pa (at 30 °C), increasing by 30% than the blank. In addition, 0.06 wt% dosage of 50 nm SiO2 leaded to significant promotion for CO2 desorption, with the maximum desorption rate at 3.9 mmol/min, and the desorption energy consumption reduced by 9.5% compared with blank case. Importantly, introduction of NPs had no significant effect on the phase splitting behavior, according to the time-profile phase-splitting measurements. The advantage influence of NPs was well validated by current DEEA-AEEA and MEA-sulfolane biphasic solvent. Furthermore, the bench-scale CO2 absorption and desorption evaluation revealed that the relative energy consumption was respectively reduced by 15.9% and 10.0%, after introduction of 50-Si-NPs and 30-Ti-NPs.