Atmospheric CO<sub>2</sub> Sequestration in Seawater Enhanced by Molluscan Shell Powders
Yuto Namikawa, Michio Suzuki
Abstract
Carbon capture, utilization, and storage (CCUS) are widely recognized as a promising technology for mitigating climate change. CO 2 mineralization using Ca-rich fluids and high-concentration CO 2 gas has been studied extensively. However, few studies have reported CO 2 mineralization with atmospheric CO 2, owing to the difficulty associated with its low concentration. In seawater, the biomineralization process promotes Ca accumulation and CaCO 3 precipitation, assisted by specific organic matter. In this study, we examined the conversion of atmospheric CO 2 into CaCO 3 in seawater using shell powders ( Pinctada fucata, Haliotis discus, Crassostrea gigas, Mizuhopecten yessoensis, Turbo sazae, and Saxidomus purpurata ). Among the six species, the shell powder of S. purpurata showed the highest rate of CaCO 3 formation and recovery of CaCO 3 . NaClO treatment test revealed that the organic matter in the shells enhanced the CO 2 mineralization. All materials used in this study, including atmospheric CO 2, seawater, and shells, are economically feasible for large-scale applications. Using shell powder for CO 2 mineralization in seawater embodies an innovative technological advancement to address climate change.