Temperature swing solvent extraction for salt and glycerin separation from wastewater

Abstract

A relatively novel temperature-swing solvent extraction (TSSE) technology was investigated for the separation of salt and glycerol from high-salt wastewater containing glycerol. Diisopropylamine (DIPA) was employed as the solvent for successfully treating ultrahigh-salinity wastewater. Experimental results indicated that the salt removal rate of TSSE technology reached up to 93.86% in saturated brine containing 10.00 wt% glycerol. After five cycles of solvent recovery, the salt removal rate remained at 84.55%. Additionally, when the glycerol mass fraction in saturated brine was 80.00 wt%, the water recovery rate of TSSE technology was 60.27%, with a salt removal rate of 92.88%. The study also analyzed the mechanism of TSSE, revealing that the difference in solubility between DIPA and NaCl in water is crucial for achieving TSSE. The unique capability of TSSE technology in treating high-salt wastewater containing organics was highlighted, achieving not only effective salt removal but also glycerol concentration. The findings of this research not only demonstrate the remarkable effectiveness of TSSE technology in addressing high-salt wastewater containing glycerol but also forecast its promising outlook and immense potential for widespread adoption in various industrial wastewater treatment sectors.