Circulation of boron resources from desalination brine through solvent extraction (TMPD/2-ethylhexanol with kerosene) and ionic-liquid extraction (ALiCy/kerosene) methods

摘要

Desalination technologies have been widely implemented since the 1970s to solve the problem of freshwater scarcity. However, brine, the by-product of the desalination process, which has a higher salinity and total dissolved solids (TDS) than seawater, can cause severe environmental problems. For instance, brine could change the composition and temperature of seawater, decrease dissolved oxygen, and influence the organisms habitat. Under this circumstance, circulating critical resources from brine is acceptable for minimizing brine disposal. This study employed two extraction systems (TMPD, 2,2,4-trimethyl-l,3-pentanediol and ALiCy, trioctyl/decylmethylammonium-bis(2,4,4-tri-methilpentyl) phosphinate), which are solvent extraction and ionic liquid extraction, to recover boron from brine. The parameters, including pH value, concentrations of TMPD and ALiCy, O/A (organic/aqueous) and I/A (ionic liquid/aqueous) ratios, contacting time, and reaction temperature of boron extraction through the TMPD and ALiCy systems, would be optimized. The results reveal that extraction efficiencies of TMPD and ALiCy systems were 93.8 and 72.3, respectively. Moreover, different agents can be evaluated to strip boron from TMPD and ALiCy. The boron product and the extractants could then be generated and reused. Briefly, the environmental hazards caused by the desalination brine and boron resources can be reduced and circulated through this research with two different extraction systems.