Room temperature ionic liquids for separating organics from produced water

An experiment was carried out to study the use on nine different ionic liquids in produced water remediation by separating organics from produced water. The distribution of polar organic compounds typical of water contaminants associated with oil and gas production was measured between water and nine hydrophobic, room-temperature ionic liquids. The organic compounds selected were representative of various classes of water-soluble organics that have been shown to contaminate produced water. Sensitivity of the distribution coefficients to salinity, temperature, concentration, and pH was investigated. The uptake of organics into the ionic liquid from the aqueous phase was measured using liquid-liquid experiments. Karl-Fischer titration was used to determine water solubility in the ionic liquid, and Ultraviolet (UV) spectroscopy was used to determine the ionic solubility in deionized water. The uptake of acetic acid was marginal in the ionic liquids tested, which may pose a problem for use in produced water remediation because acetic acid is the most important organic constituent. The results show that ionic liquids may be very effective in the selective removal of particular contaminants in produced water, and yet may be almost ineffective to other contaminants such as paraffinic organic compounds.