CAREER: Toward Geomimetic Concretes

受地壳中奇异化学反应的启发，该奖项侧重于对流固界面化学反应的基本理解，并利用这一基本见解设计碳负的仿地混凝土材料。普通波特兰水泥混凝土的生产约占全球人为碳排放的7%，占全球工业淡水抽水量的约9%。这就需要开发基础设施材料，不仅要有碳汇，还要有节水意识。在设计这种可持续材料技术方面的进展，原则上被二氧化碳-水-固体界面上发生的复杂化学反应所混淆。在了解这种非均相化学反应的机理图景方面的突破不仅有利于生态友好型建筑材料的设计，而且在调整土壤宿主反应、确定污染物在地质系统中的命运以及理解环境催化方面也具有重要意义。该学院早期职业发展(Career)奖还将推动协同教育努力，在K-12和本科生中强调可持续建筑材料的重要性，特别是双语拉美裔初学者，他们是美国英语学习人口的重要组成部分。当谈到用增湿的富含二氧化碳的流体描述碳化过程时，长期存在的通过溶解-沉淀过程的大宗水溶液流体介导的碳化过程的范例变得完全不相关。这种范式的变化在地质环境中尤其明显，有报道称，贫水流体中的碳矿化加速。碳化动力学的增强被认为与界面水膜的形成密切相关，界面水膜具有独特的反应物/溶剂的化学物理性质，并作为纳米限制浴有效地介导化学反应。尽管开发碳酸盐混凝土具有巨大的技术意义，但界面过程的机理图仍然难以捉摸，这些过程是导致水纳米膜反应活性增强的原因，以及相关的热力学和动力学。通过结合分子模拟以及原位和非原位光谱技术，这项研究提供了对纳米受限过程的分子水平的理解，这些过程支配着纳米受限介质中的碳矿化。这些过程包括纳米多孔介质中的多相流体分离、纳米受限结晶过程以及吸附水层和阳离子淋滤玻璃硅酸盐中的扩散传质。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Inspired by the exotic chemical reactions in earth’s crust, this award focuses on the fundamental understanding of the chemical reactions at the fluid-solid interfaces and leverages this basic insight to design carbon-negative geomimetic concrete materials. The production of ordinary Portland cement-based concretes is responsible for about 7 percent of global anthropogenic carbon emissions and about 9 percent of industrial freshwater withdrawals worldwide. This necessitates the development of infrastructure materials that are not only carbon sink but also water conscious. The progress in designing such sustainable material technologies is in principle confounded by the complexity of chemical reactions occurring at the carbon dioxide-water-solid interfaces. The breakthrough in understanding the mechanistic picture of such heterogenous chemical reactions will not only benefit the design of eco-friendly construction materials, but also entails numerous implications in tuning soil-hosted reactions, determining the fate of contaminants in the geosystems, and understanding environmental catalysis. This Faculty Early Career Development (CAREER) award will also instigate synergistic educational efforts to engrave the significance of sustainable construction materials in K-12 and undergraduate students, especially bilingual Hispanic early-learners, who make up a significant portion of the US English language learner population. When it comes to describing the carbonation process with humidified CO2-rich fluids, the long-standing paradigms for bulk aqueous fluid-mediated carbonation via the dissolution-precipitation process become simply irrelevant. Such a change in paradigm is particularly evidenced in geological settings with reports of accelerated carbon mineralization in water-poor fluids. The enhanced carbonation kinetics is hypothesized to be closely related to the formation of interfacial water films that exhibit unique reactant/solvent chemophysical properties and serve effectively as a nano-confining bath mediating chemical reactions. Despite the vast technological implications in developing carbonated concretes, the mechanistic picture of the interfacial processes accountable for the enhanced reactivity in water nanofilms and the associated thermodynamics and kinetics remain elusive. By integrating molecular simulations and in situ and ex situ spectroscopy techniques, this research provides a molecular-level understanding of the nanoconfined processes that govern carbon mineralization in nanoconfined media. These processes include multi-phase fluid segregation in nanoporous media, nanoconfined crystallization processes, and diffusive mass transport in the adsorbed water layers and cation-leached glassy silicates.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.