1,4-Dioxane
1,4-dioxane is a synthetic chemical that was primarily used as a stabilizer for 1,1,1-trichloroethane and is therefore often commingled with other chlorinated solvent contaminants. it has also been used as an alternative to tetrahydrofuran in some manufacturing processes.
Due to the physical properties (low sorption and high solubility), 1,4-dioxane in groundwater often travels much farther than other chlorinated solvents.
Applicable Remediation Technologies for 1,4-Dioxane
Air Sparging: Poor to Good – While the vapor pressure is greater than 1 mm Hg, air sparging can be ineffective due to the high solubility and low Henry’s constant of 1,4-dioxane. The key for air sparging to work is a significantly longer sparging residence time than compounds commonly treated with this technology.
SVE: Poor – While the vapor pressure is greater than 1 mm Hg, SVE is ineffective due to the high solubility of 1,4-dioxane. For SVE to be effective, the soils need to be dry.
Thermal: Good – Thermal processes can be used to increase the Henry’s constant for 1,4-dioxane, making it partition more readily into the vapor phase.
Pump and Treat: Good – Pump and treat is usually not an effective source remedy for groundwater remediation, when there is significant non-aqueous mass present (absorbed to soil or non-aqueous phase liquids). As 1,4-dioxane is found primarily in the aqueous phase, this is one of the few compounds where pump and treat could be effective as a source reduction technology.
Aerobic: Good – Has been shown to degrade via a cometabolic pathway, which often requires the presence of oxygen and a simple hydrocarbon (like propane), or directly through biodegradation. Degradation can be inhibited by chlorinated ethenes or occurs very slowly. Therefore not practical at all sites.
Anaerobic: Poor – Has not been shown to be effective.
Activated Carbon: Poor – 1,4-dioxane can adsorb to activated carbon in small quantities, making this method potentially cost prohibitive.
Synthetic Resins: Excellent – Synthetic resins can be used to collect various contaminants from liquids, vapor or atmospheric streams and be reused indefinitely. Potentially significant upfront capital costs.
Molecular weight (g/mol): 88.107
Solubility (mg/L): Completely Miscible
Vapor pressure (mm Hg): 38.09
Henry’s Coefficient (unitless): 0.7236304
Organic Carbon Partitioning Coefficient (cm3/g): 94.94
