(Georgia Institute of Technology, 2021-07-07)
Pital, Aaron C.
Precipitate produced by the interaction of aqueous reactant solutions in a microchannel is evaluated through instrumental analysis and numerical modeling. Instrumental analysis of analogs of iron sulfide, iron carbonate, and iron phosphate minerals and the effect of modeled ionic strength and mass transport mechanisms are presented. Implications on fluid dynamics due the production of colloids at a solution-solution interface is developed. A phenomenon of electroless reduction in this system transitioning to self-catalyzed electrodeposition is presented in light of the dynamics previously discussed and is used as an example of the convergent effects of coupled physiochemical systems on the microscale. All three of the above results (precipitate analysis, fluid and mass transport dynamics, and coupled physiochemical systems) are leveraged to present results of the interaction of organic species with precipitating iron sulfide material. It is found that the presence of organic species has a strong impact on the morphology of iron sulfide mineral analogs, and that morphology may be diagnostic for the presence of organics during formation even when Raman spectra show no signs of extant organic material. This has profound implications for the use of autonomous rovers in exploring the organic-mineral interactions of ancient aqueous systems such as Mars’s Jezero Crater.