New insight into absorption characteristics of CO2 on the surface of calcite, dolomite, and magnesite

An electrochemical method and multiscale simulations were used to study adsorption performances of CO2 on the surface of three minerals (calcite, dolomite, and magnesite). Experimental results show that dolomite has the optimum adsorption performance at different temperatures due to shorter adsorption time and larger adsorption capacity. The adsorption process of CO2 can be described by the pseudo-first-order kinetic model. The adsorption rate constant of magnesite is the largest and that of calcite is the smallest, but the adsorption rate constant of dolomite is closer to that of magnesite. Unexpectedly, multiscale simulations show that the adsorption interface of CO2 can be divided into strong and weak adsorption layers. Under saturated adsorption conditions, the adsorption capacity of CO2 is determined by the weak adsorption layer. Results highlight the importance of the effective adsorption distance for the first time. Furthermore, it confirms that the effective adsorption distance of calcite is the longest and that of magnesite is the shortest, but the effective adsorption distance of dolomite is closer to that of calcite. These findings could contribute to design advanced CO2 capture and sequestration techniques for achieving both improved shale gas production as well as alleviate the greenhouse effect.

Automated summary

The study found that dolomite has the best CO2 adsorption performance at different temperatures, and the adsorption process follows the pseudo-first-order kinetic model. Additionally, multiscale simulations revealed that the adsorption interface of CO2 can be divided into strong and weak adsorption layers, with the weak adsorption layer determining the adsorption capacity under saturated conditions.