Vibrational Spectroscopy of Complex Synthetic and Industrial Products

Arsenic and its adverse effects on the environment and society impose a serious risk as it can be observed in cases such as India, Bangladesh, Vietnam, Nepal, and Cambodia. These problems can arise from geochemical processes but also man-made activities like mining and processing of minerals (Copper, Gold, Cobalt, Nickel and Uranium) that may further contribute to the risk of environmental disasters. In either case, problems and environmental disasters maybe prevented if a detailed chemical identification and understanding of the arsenic species and their chemical properties such as solubility is understood. The processing of these mineral ores (containing various metals) generates arsenic-containing solid wastes which are disposed in tailings management facilities outside in the environment (Riveros et al., 2001; Dymov et al., 2004; Defreyne et al., 2009; Mayhew et al., 2010; Bruce at al., 2011). Most often the phases that are produced after the process is completed is often a multicomponent in nature and contains a variety of elemental and individual phases (often ≥ 3-10 phases are expected to be present at the end of the process) produced produced along the chemical process. To complicate the understanding of these phases even more, depending upon the processing conditions, the produced unwanted materials (from an economic and recyclable aspect) may also be of a poorly crystalline nature (nano-scale order) in addition to being multicomponent in nature and as such, simple tasks such as identification and then inferring understanding of its chemical properties (such as arsenic release into the environment) becomes very difficult if not nearly impossible. In general, as a result of their multicomponent nature, and perhaps due to historical relation, the use of lab based XRD has been the main tool to tackle the identification of these phases via the use of peak matching and Rietveld type of phase fitting analysis. Recently, synchrotron based soft and hard X-ray techniques (XANES and EXAFS) have been used in a similar fashion to overcome the poorly crystalline (lack of long range order) and multicomponent barrier of these industrially produced complex samples using similar types of mathematical types of fitting routines (Principal Component Analysis and Target Transformation) which still have limitations in identifying mixtures (>2-3) of similar phases with various coordination numbers/environments for the same probing atom of interest. The need to develop alternative energy storage devices has become one of the main focuses in North America and around the World as a result of the fact that as the population of the world increases, our oil energy supplies are steadily and quickly decreasing with time.