Mass transfer and chemical oxidation studies for TCE treatment in aqueous and soil systems.

摘要

The solubility of trichloroethylene (TCE), an ubiquitous hazardous pollutant, was investigated in selected alcohols and household detergents in batch experiments. Three cosolvents (ethanol, butanol and propanol) and three household surfactants/detergents (WiskRTM, TideRTM and Arm & Hammer RTM) were compared using bench scale batch aqueous studies leading to the selection of propanol and TideRTM for further study. TCE solubility of 10,000 ppm (muL/L) was accomplished by a 20,000ppm (muL/L) TideRTM solution while 39,000 ppm TCE solubility was accomplished by a 500,000ppm propanol solution. In comparison, solubility of TCE in water is 750 ppm (muL/L). Direct head to head comparison of propanol and TideRTM showed that 1% TideRTM solution produced TCE solubility enhancement comparable to a 30% propanol solution. Aqueous phase systems were employed to develop ternary phase diagrams for both Propanol-Water-TCE & TideRTM-Water-TCE systems. The results indicated a higher miscibility (larger single phase region on the ternary phase diagram) for the TideRTM-water mixture compared to propanol-water mixture, supporting the greater solubilizing power of Tide compared to propanol. The properties of TideRTM such as, pH, possible degradation in light and absorbance by UV-Vis-NIR Spectroscopy were investigated to add understanding to its behavior in aqueous and soil systems contaminated by TCE. Reaction of TideRTM with the chemical oxidant potassium permanganate was studied to determine reaction mass ratios and mass depletion constants for the reaction over a range of pH values. Bench scale batch experiments using silica sand were conducted to determine the resistance of sand to the mass transfer of TCE in Tide RTM solutions, and were used to establish a relationship between the amount of sand present and the potential for mass transfer of TCE to the aqueous solution.;This study has provided parameters for a process design by which Tide RTM can be used to effectively remove small amounts of TCE from aqueous and sand systems and KMnO4 can be used to subsequently oxidize and remove both TideRTM and TCE components from the produced effluent. In addition, the maximum possible efficiency of 2% Tide RTM solution (by volume) can be predicted for both aqueous and sand systems at near atmospheric pressure and 24° Celsius.