In this thesis, three techniques are integrated to investigate how best to capture and parameterize complexity in interfacial reactions at mineral-aqueous interfaces. The first chapter employs a novel approach that leans on spectroscopic and computational data to build a Surface Complexation Model for aluminum-doped ferrihydrites. The model places Al on the surface in Fe1 sites and was found to fit empirical zeta potential measurements reasonably well. In chapter two, Flow Adsorption Microcalorimetry and Density Functional Theory calculations were each used to derive the enthalpies of phosphate, oxalate, and chromate sorption on the (110) face of rutile. The difficulty in determining the masses adsorbed in the experiment, and the complexity of electron interactions in our computational calculations, did not allow for a reconciliation of adsorption enthalpies. Although we successfully captured the complexity associated with substitution, we were unable to rationalize differences in deriving thermodynamics parameters.