Our research article on using temperature swing solvent extraction (TSSE) desalination for zero liquid discharge (ZLD) has been accepted for publication in Environmental Science & Technology!
Zero liquid discharge of hypersaline brines is technically and energetically challenging. In this study, we demonstrate the membrane-less and non-evaporative desalination technique of TSSE can achieve ZLD treatment of ultrahigh salinity brines. Utilizing a low-polarity solvent to extract water from brine and then releasing the water as product with the application of low-temperature heat, TSSE with diisopropylamine attained complete extraction of water from a hypersaline feed simulated by 5.0 M NaCl solution (≈292 g/L TDS). Practically all the salt is precipitated as mineral solid waste and the product water contains <5% of NaCl relative to the initial feed. Recyclability of the solvent was demonstrated with three repeated semibatch TSSE cycles of consistent ZLD performance. This study establishes the potential of TSSE as a more sustainable alternative to current thermal evaporation methods for zero liquid discharge of ultrahigh salinity brines.
