Use of Diffuse Reflectance Spectroscopy to Determine Desorption Coefficients of Trichioroethylene from Powdered Soils

摘要

This laboratory thesis investigated the applicability of reflectance spectroscopy as a tool to measure desorption rates by directly observing the change in trichloroethylene bound to surface sites. Diffuse reflectance spectroscopy holds the promise of being a faster technique with minimal sample preparation time. Reflectance spectroscopy's dependence on the surface of the sample is its greatest advantage, as well as its greatest disadvantage. Both high and low resolution scans were made of different soil samples contaminated by trichloroethylene. After the technique of spectral subtraction was used, potential TCE signals were observed from the dolomitic limestone sample. Unfortunately, due to the low level of the signal and high amount of noise, positive identification of the signals as TCE could not be established. The low resolution scans were unable to detect any possible TCE signals. More data is required to determine the sensitivity of the device as well as prove the linearity of the signal with concentration, before this technique can be proven to be useful for studying desorption kinetics.