A research group, led by Ms. Zihua Shao (doctoral student), Project Researcher Yunfeng Liang (at the University of Tokyo at the time) and Prof. Takeshi Tsuji from the Graduate School of Engineering, the University of Tokyo, has discovered a new chemical mechanism through which CO2 directly reacts with basaltic mineral surfaces, forming carbonates without dissolving in water.
This breakthrough challenges the long-standing paradigm that CO2 must first dissolve in water before mineralizing. Instead, the study shows that CO2 molecules can chemisorb onto nonbridging oxygen sites and hydroxyl groups on naturally hydrolyzed mineral surfaces. These surface reactions result in the rapid formation of carbonate species such as CO32-, HCO3-, and HC2O5-, a mechanism that explains the unexpectedly fast CO2 mineralization rates observed in recent field projects in Iceland and the U.S. By establishing a direct link between mineral structure and surface reactivity, this work paves the way for more safe and efficient carbon sequestration strategies that leverage the unique geochemistry of igneous rocks.
These findings provide a theoretical foundation for site selection and geochemical modeling of future CO2 storage projects. In particular, they highlight Japan’s potential to lead in CO2 mineralization, given its widespread distribution of basaltic formations.
Illustration of three distinct reaction pathways for CO2 chemisorption onto igneous mineral surfaces
Papers
Journal: Environmental Science & Technology
Title: Surface reaction of CO2 with basaltic minerals as a mechanism for carbon mineralization
Authors: Zihua Shao, Jihui Jia, Yunfeng Liang*, Wuge Cui, Gyuhwan Jo, Keishi Usui, Tomohiro Taniguchi, Takeshi Tsuji*