Cosolvent effects of alcohols on the Henry's law constant and aqueous solubility of tetrachloroethylene (PCE)

The effects of selected cosolvents ethyl alcohol (EtOH), isopropyl alcohol (IPA), and tertbutyl alcohol (TBA) on the Henry's law constant (H) of tetrachloroethylene (PCE) in aqueous solutions were investigated using the static headspace method. Alcohols in solution at a concentration around 20% and above acted as cosolvents increasing the aqueous solubility of PCE, which resulted in lower H values for PCE as compared to the value of H in deionized water. TBA, the most hydrophobic of the three alcohols, exhibited the strongest cosolvent effects, while EtOH had the weakest effects. A ln-linear relationship was observed between H and the volumetric fraction of alcohol added. Investigation of the solubilization of PCE in alcohol solutions confirmed the cosolvent trend observed for the three alcohols. A ln-ln relationship was observed between H and the enhanced solubility of PCE at a particular alcohol concentration. It was also observed that the value of H is a function of the enhanced solubility regardless of the type of cosolvent used. The results from this research further define the behavior of PCE in alcohol flooding solutions used in the remediation of PCE contaminated media.