Department of Earth and Environmental Engineering, Department of Chemical Engineering, and Lenfest Center for Sustainable Energy, Columbia University, New York, NY 10027, USA.
Phys Chem Chem Phys. 2013 Sep 28;15(36):15185-92. doi: 10.1039/c3cp52459k.
Carbon mineralization has recently received much attention as one of the most promising options for CO2 sequestration. The engineered weathering of silicate minerals as a means of permanent carbon storage has unique advantages such as the abundance of naturally occurring calcium and magnesium-bearing minerals and the formation of environmentally-benign and geologically stable solids via a thermodynamically favored carbonation reaction. However, several challenges need to be overcome to successfully deploy carbon mineralization on a large scale. In particular, the acceleration of the rate-limiting mineral dissolution step along with process optimization is essential to ensure the economic feasibility of the proposed carbon storage technology. In this study, the effect of various types of chelating agents on the dissolution rate of calcium-bearing silicate mineral, wollastonite, was explored to accelerate its weathering rate. It was found that chelating agents such as acetic acid and gluconic acid significantly improved the dissolution kinetics of wollastonite even at a much diluted concentration of 0.006 M by complexing with calcium in the mineral matrix. Calcium extracted from wollastonite was then reacted with a carbonate solution to form precipitated calcium carbonate (PCC), while tuning the particle size and the morphological structure of PCC to mimic commercially available PCC-based filler materials.
碳矿化作用最近受到了广泛关注，因为它是二氧化碳封存的最有前途的方法之一。通过硅酸盐矿物的工程风化来实现永久碳储存具有独特的优势，例如自然界中钙和镁含量丰富的矿物质，以及通过热力学有利的碳化反应形成环境友好且地质稳定的固体。然而，要大规模成功地部署碳矿化作用，还需要克服一些挑战。特别是，要加速限速的矿物溶解步骤并进行工艺优化，以确保所提出的碳储存技术的经济可行性。在这项研究中，探讨了各种类型的螯合剂对含钙硅酸盐矿物硅灰石的溶解速率的影响，以加速其风化速率。结果发现，即使在 0.006 M 的非常稀释的浓度下，螯合剂（如乙酸和葡萄糖酸）通过与矿物基质中的钙配位，也能显著改善硅灰石的溶解动力学。从硅灰石中提取的钙然后与碳酸盐溶液反应形成沉淀碳酸钙（PCC），同时调整 PCC 的颗粒大小和形态结构，以模拟市售的基于 PCC 的填充材料。
