Effect of sucrose on CO2 storage, vaterite content, and CaCO3 particle size in indirect carbonation using seawater

Indirect carbonation is a technology for carbon capture, utilization, and storage that is used to reduce the concentration of CO2, and it may be also used to produce vaterite for drug delivery materials. However, vaterite is difficult to produce at the sizes and production volumes required for these applications. In this study, we investigated the effects of sucrose additions to seawater in an indirect carbonation process to increase CO2 storage, generate vaterite, and reduce CaCO3 particle size. In addition, sucrose was added before and after Ca elution and the CO2 storage, vaterite content, and CaCO3 particle size results were compared. By adding sucrose to seawater, the CO2 storage capability was doubled, the vaterite content increased by 34%, and the CaCO3 particle size decreased by 41% compared to results using seawater alone. When the molar ratio of sucrose to Ca in the Ca eluate was 1:2, the vaterite content was at its highest and the particle size was the smallest. At this ratio, the supersaturation of the Ca eluate was maximized due to the high Ca concentration and pH. Adding sucrose before Ca elution had many advantages compared to adding sucrose after Ca elution: the vaterite content increased, the particle size decreased, and most significantly, CO2 storage and CaCO3 production doubled and the addition of NaOH for carbonation was unnecessary. Because seawater and sucrose used in this study are non-toxic and inexpensive, the economical mass production of small-sized pure vaterite using this technology is feasible.