Improved the CO2 adsorption performance in cobalt oxide nanoparticles in the presence of DES

With the rapid industry development in the last decades, air pollution has increased with the increase in carbon dioxide (CO2). Adsorbents are considered a good candidate for capturing CO2 owing to their many advantages, such as reusability, low cost, easy operation, and scale-up synthesis. In this study, the synthesis of mesoporous cobalt oxide (Co3O4) nanoparticles (NPs) in deep eutectic solvent (DES) is reported by the ultrasound-assisted method to improve the CO2 adsorption performance. The synthesized Co3O4 NPs were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), and Brunauer-Emmett-Teller (BET) for investigating morphology, crystallinity, and porosity. CO2 and N-2 adsorption isotherms of Co3O4 NPs synthesized in DES and synthesized in water were measured by quartz crystal microbalance (QCM) at a temperature range of 288.15-308.15 K and pressures of up to 5 bar. In addition, CO2/N-2 selectivity adsorption on the Co3O4 NPs was investigated. Furthermore, adsorption isotherms were correlated to the Langmuir isotherm model. The results reveal that the adsorption performance of Co3O4 NPs synthesized in DES improved in comparison with Co3O4 NPs synthesized in water. The Co3O4 NPs' molar enthalpy of adsorption showed that the CO2 adsorption process is exothermic.

Automated summary

With the rapid industry development, air pollution has increased due to the increase in carbon dioxide. Adsorbents, with their advantages of reusability, low cost, easy operation, and scale-up synthesis, are considered a good option for capturing CO2. This study reports the synthesis of mesoporous cobalt oxide nanoparticles in deep eutectic solvent using the ultrasound-assisted method to improve CO2 adsorption performance. The results show that the adsorption performance of the synthesized nanoparticles in deep eutectic solvent is better than those synthesized in water, and the CO2 adsorption process is exothermic.