Carbon Dioxide Sorption Isotherm Study on Pristine and Acid-Treated Olivine and Its Application in the Vacuum Swing Adsorption Process

This paper investigates the potential of pristine and acid-treated olivine as a substrate for CO2 capture using a vacuum swing adsorption (VSA) process from the gas-solid phase. The experiments tested the isotherm of pure CO2 adsorption with partial pressure from 10(-5) to 1 bar at ambient temperature. The CO2 adsorption capacity and actual expected working capacity (EWC) curves of pristine and acid-treated olivine were determined. Isotherm studies predict that physisorption dominates chemisorptions at ambient temperatures. The adsorption capacity enhances with the increase of specific surface area, pore volume, and the appearance of Mg complexed on the mineral's surface. Actual EWC studies showed that acid-treated olivine is an adsorbent choice for the VSA process, due to enhanced CO2 adsorption capacities compared to olivine and the potential for 100% recovery of CO2 during the regeneration process. Pristine olivine is not suitable for the VSA process because of bad regenerability, but it can be used in capturing and sequestering dilute CO2 in process streams. Our research reveals excellent viability for the application of VSA in the area of CO2 capture using pristine olivine and acid-treated olivine.