Speciation, structure and hydration of solutes under hydrothermal conditions

许多地质和工业过程发生在远远超出常规室温测量范围的条件下。本提案的目标是发展知识基础和理论理解，以描述在发电站、先进核反应堆、地热矿体、深海热液喷口遇到的极端温度和压力下水系统的行为，以及二氧化碳的捕获和封存。******灵敏的流量量热计和密度计，由惰性材料构成，可承受腐蚀条件，将用于确定温度高达400℃和压力高达350个大气压的液态水中简单电解质和有机分子的热力学性质，以检查离子电荷和有机官能团在接近水临界点的条件下的影响。化学物质的形态及其平衡常数将通过在新型高温高压流动电池中使用紫外可见光谱、拉曼光谱、量热法、密度法和一种独一无二的高精度电导仪进行原位测量来确定，所有这些都能够达到亚临界或超临界条件。这些测量将对溶质水化和溶质-溶质相互作用的基本性质产生新的见解。该项目还将产生热力学数据、传输特性、半经验模型和理论方法，用于预测水基地热系统和在极端温度和压力下运行的先进工业技术中的水性无机和有机溶质的特性和相行为。******该计划将集中在三个方面：(i)基础研究，以了解形态形成和离子-离子相互作用对汽液临界轨迹和250℃以上电解质溶液的较低临界溶液温度的作用；（ii）与碳捕获和地质封存有关的二氧化碳和（二氧化碳+胺）溶液在中高温下的热力学和相行为；(3)生命起源前分子的热力学和动力学稳定性，需要对热液生命起源的假设机制进行建模。这项工作的新颖之处在于所研究的非常极端的条件，识别异常效应的潜力，以及开发专门的仪器技术来获得这些非常恶劣条件下复杂水系统的定量数据的需求。

Many geological and industrial processes take place at conditions far beyond the range of conventional room temperature measurements. The objective of this proposal is to develop the knowledge base and theoretical understanding needed to describe the behaviour of aqueous systems at extremes of temperature and pressure encountered in electrical power stations, advanced nuclear reactors, geothermal ore bodies, deep-ocean hydrothermal vents, and the capture and sequestration of CO2. ******Sensitive flow calorimeters and densitometers, constructed of inert materials to withstand the corrosive conditions, will be used to determine the thermodynamic properties of simple electrolytes and organic molecules in liquid water at temperatures up to 400 oC and pressures as high as 350 atmospheres, to examine the effects of ionic charge and organic functional groups under conditions approaching the critical point of water. The form of the chemical species, and their equilibrium constants, will be determined by in situ measurements in novel high temperature, high pressure flow cells using UV-visible spectroscopy, Raman spectroscopy, calorimetry, densimetry and a one-of-a-kind, high-precision conductance apparatus, all capable of reaching sub-critical or supercritical conditions. These measurements will yield new insights into the fundamental nature of solute hydration, and solute-solute interactions. The project will also yield thermodynamic data, transport properties, semi-empirical models, and theoretical methods for predicting the properties and phase behaviour of aqueous inorganic and organic solutes in water-based geothermal systems and advanced industrial technologies that operate under extremes of temperature and pressure.******The program will focus on three areas: (i) basic research to understand the role of speciation and ion-ion interactions on the vapour-liquid critical locus and the lower critical solution temperature of electrolyte solutions above 250 oC; (ii) the thermodynamics and phase behaviour of CO2 and (CO2 + amine) solutions at intermediate and high temperatures relevant to carbon capture and geological sequestration; and (iii) the thermodynamic and kinetic stability of pre-biotic molecules required to model postulated mechanisms for the hydrothermal origin of life. The novelty in the work lies in the very extreme conditions being studied, the potential for identifying unusual effects, and the need to develop specialized instrumental techniques to obtain quantitative data for complex aqueous systems under these very aggressive conditions.