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Determination of concentrations in solutions in gaseous, liquid, and supercritical carbon dioxide by means of UV Raman spectroscopy

Posted on:2002-03-01Degree:Ph.DType:Thesis
University:Wayne State UniversityCandidate:Tang, HaofengFull Text:PDF
GTID:2461390011495616Subject:Chemistry
Abstract/Summary:
The promising engineering properties of supercritical CO2 have attracted the attentions of researchers from various fields, especially those from biomaterial extraction and polymer processing.;However, when more than one components are present, it is even difficult to make on-line measurement, hindered by the high pressure of the system. Until now, most of the previous investigations employed off-line measurement. This is unfavorable because (1) An off-line approach would affect the system property, hence losing some insight in the system; (2) Off-line approach has no chance to capture information on composition gradient in a system with high density, supercritical CO2 system.;Effort has been made to apply spectroscopy in the study of high-pressure systems. Among them only a few were on quantitative measurement.;In this thesis work, UV Raman Scattering spectroscopy was proposed as a novel approach. Experimental procedure and data analysis methodology were established for the study of polymer solubility behavior in supercritical CO2 system. The conclusion is that UV Raman spectroscopy constructs an accurate, feasible and convenient approach for quantitative composition measurement of high-pressure system.;As a by-product of the research, it is also discussed in the dissertation that a large mirage effect was observed in a supercritical fluid with non-uniform temperature gradient.
Keywords/Search Tags:Supercritical, UV raman, Spectroscopy
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