Optimization of Hydrophobic Deep Eutectic Solvent for Boron Extraction Along with the Recyclability and Reusability of the Solvent.

This work incorporates a hydrophobic Deep Eutectic Solvent (DES) that targets the removal of boron element from wastewater streams. The hydrophobic DES comprises of 1-Decanol (Dec) as a hydrogen bond acceptor (HBA) and 2,2,4-Trimethyl-1,3-pentanediol (TMPD) as a Hydrogen Bond Donor (HBD) with the molar ratio of Dec to TMPD of 4:1. To optimize the boron Extraction Efficiency (EE) of the DES through Liquid-Liquid Extraction (LLE), Design of Experiments (DoE) methodology was assigned with Box-Behnken Design (BBD). Besides, the optimization the operational conditions from industrial and economical points of view reached up 93.1±0.6 with a percentage difference of 1.5% from the predicted one by the model. The reusability of the boron loaded DES was examined by using the dirty DES over three cycles of LLE without regenerating it. The first, second and third cycle showed an extraction efficiency of 95.1±0.1, 89.3± 0.1% and 85.6±1.8 %, respectively. The regeneration process was examined over different mass ratios of the stripping solution (0.1 M NaOH) to the dirty DES. The optimum regeneration of the boron loaded DES achieved as 97.1± 1.1% at a mass ratio of stripping solution to dirty DES of 1:1. This is a strong evidence to emphasize the sustainability of the synthesized DES and its economical and industrial scalability.