Organic ligand complexation reactions at the mineral-water interface play an important role in several environmental and geochemical processes such as adsorption, dissolution, precipitation, pollutant transport, nutrient cycling, and colloidal stability. Although organic ligand surface complexation reactions have been extensively studied, a molecular level understanding regarding the mechanisms underlying the adsorption of such compounds is still limited. The purpose of the current study was to investigate the interactions between some common naturally occurring organic ligands and a common aluminosilicate clay mineral, kaolinite, using a combination of macroscopic and microscopic experimental methods. Molecular level information regarding the structure and binding mode of adsorbed species was obtained using in situ MIR-FTIR spectroscopy. Other experimental techniques including adsorption experiments, surface titrations, and surface complexation modelling were also employed in order to quantify and describe the macroscopic adsorption properties of the organic ligands examined. Three low molecular weight organic acids (oxalic, salicylic, and phthalic acid) and humic acid were chosen as representative organic ligands. Spectroscopic evidence revealed that low molecular weight organic acids are able to form both inner and outer sphere complexes on kaolinite, and the relative concentrations of these surface complexes varies with solution chemistry. Inner sphere coordination modes inferred are a mononuclear bidentate for oxalate (five-membered chelate ring) and phthalate (seven-membered chelate ring); and a mononuclear monodenate (six-membered pseudochelate ring) for salicylic acid. Similar coordination modes were shown to form on simpler mineral (hyrd)oxides. Elucidation of the coordination chemistry of these ligands can provide insights into the dissolution mechanisms of silicate minerals In contrast to low molecular weight organic acids, there was no evidence of inner sphere complexation by humic acid acids on kaolinite or gibbsite. The combined spectroscopic and macroscopic adsorption results suggest that cation bridging and van der Waals interactions are the two most probable mechanisms for the adsorption of humic acid by these mineral substrates. This finding casts doubts over the use of low molecular weight organic acids as humic acid analogs.

Printed circuit board manufacturing involves subtractive copper (Cu) etching where fine features are developed with a specific spatial resolution and etch profile of the Cu interconnects. A UV-Vis ATR metrology, to characterize the chemical transitions, has been developed to monitor the state of the bath by an in-situ measurement. This method provides a direct correlation of the Cu etch bath and was able to predict a 35% lower etch rate that was not predicted by the three current monitoring methods (ORP, specific gravity, and conductivity). Application of this UV-Vis ATR probe confirmed that two industrial etch baths, in identical working conditions, confirmed a difference in Cu2+ concentration by the difference of the near IR 860nm peak. The scope of this probe allowed chemically specific monitoring of the Cu etch bath to achieve a successful regeneration for repeated use. Interlayer dielectrics (ILDs) provide mechanical and electrical stability to the 3D electrical interconnects found in IC devices. It is particularly important that the structural support is created properly in the multilayered architecture to prevent the electrical cross signaling in short range distances. A combined multiple internal reflection and transmission FTIR has been employed for the characterization of silicon oxycarbonitride (SiOCN) films. These dielectric low-k films incorporate various functional groups bonded to silicon and require chemical bonding insight in the transformation and curing process. Distinct SiOx bonding patterns were differentiated, and the structure of the films can be predicted based on the amount of Si network and caged species. Further optimization of the FTIR analysis must minimize interference from moisture that can impact the judgement of peak heights. To accommodate this, a high-quality glove box was designed for dry air feedthrough to achieve a 95% moisture reduction during analysis, where less than 0.1 mAbs of moisture is detected in the spectra (without additional correction). The glove box allows for the rapid analysis of multiple sample throughput to outpace alternative characterization methods while retaining low spectral noise and a dry environment for 24/7 analysis. There is a great need to identify new catalysts that are suitable for tackling current economic demands, one of which is the nitrogen reduction reaction (NRR). The development of the surface enhanced infrared absorption spectroscopy (SEIRAS) has been applied to characterize the NRR mechanisms on the vanadium oxynitride electrocatalyst. Electrochemical measurements demonstrate NRR activity that is up to three times greater in the presence of N2 than the control Ar. FTIR operando suggests that a considerable number of intermediates were formed and continued to increase in absorbing value under an applied potential of -0.8 V vs Ag/AgCl. XPS results of the post-NRR film suggest a restricting of the film where vanadium oxynitride films are prone to instabilities under the possible MvK mechanism. After 90 minutes of NRR, the NH3 generated was approximately 0.01 ppm was calculated for through the salicylate colorimetric method. On-going efforts are focusing on optimizing the vanadium oxynitride film by the tuning of the oxynitride ratios and crystalline properties to promote the formation of V≡N: during the nitrogen reduction reaction.