Aqueous electrolytes and non-electrolytes under hydrothermal conditions

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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, nuclear reactors, geothermal ore bodies, deep-ocean hydrothermal vents, and the thermal recovery of heavy oil.   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°C and pressures as high as 350 atmospheres, in order 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 at high temperature and pressure, will be determined by UV-visible spectroscopy in a newly-developed flow system with sapphire windows, by static and flow-cell solubility techniques, and with a one-of-a-kind, high-precision conductance apparatus capable of reaching supercritical conditions.  Diamond anvil and high pressure flow cells will be used in conjunction with confocal Raman microscopy to examine phase relations and to identify major chemical species by direct observation at extremes of temperature and pressure.  A new project will examine the stability of pre-biotic molecules under conditions encountered in  hydrothermal vents. The novelty in the work lies in the very extreme conditions being studied, the potential for identifying unusual effects, and the need to develop specialised instrumental techniques to obtain quantitative data for complex aqueous systems under these very aggressive conditions.