Citric acid facilitates diisopropylamine separation from water: A potential solution for groundwater remediation

Diisopropylamine (DIPA) is used in various industrial processes, such as the Sulfinol™ process to remove acidic components from oil and gas, and in the production of pesticides. It has relatively high solubility in water (≈100 g/L) and is found as a contaminant in groundwater. This study uses for the first time natural citric acid (CA) to purify water contaminated with DIPA with low energy costs. CA leads to the bulk separation of DIPA from concentrated aqueous mixtures, as demonstrated using attenuated total reflectance–Fourier transform infrared spectroscopy. Therefore, it offers a potential emergency response in the case of large spills. CA also enhances the volatilization of DIPA from aqueous solutions, as demonstrated using nuclear magnetic resonance. Therefore, it also offers a potential approach to facilitate stripping of DIPA from water in pump and treat, where groundwater is extracted, treated at the surface and reinjected. These findings suggest that CA can serve as a sustainable and effective tool to treat DIPA contamination. • Citric acid decreases the miscibility of diisopropylamine in water • Other carboxylic acids also decrease the miscibility of diisopropylamine in water • Citric acid enhances diisopropylamine volatilization from water • Citric acid can be used for the remediation of water contaminated by diisopropylamine