Separation Science and Technology, Vol.40, No.7, 1415-1424, 2005
Equilibrium of boron extraction with 2-butyl-2-ethyl-1,3-propanediol and 2-ethylhexanol in butyl acetate
Boron extraction with 2-butyl-2-ethyl-1,3-propanediol (BEPD) and 2-ethylhexanol (EHA) in butyl acetate (BA) was carried out at various boron and extractants concentrations. The distribution ratio of boron was constant for all boron concentrations when EHA was used as the extractant, and it increased with EHA concentration. When high concentrations of BEPD were used as the extractant, the distribution ratio of boron was almost the same for all boron concentrations. The distribution ratio of boron increased with BEPD concentrations. An increase in the initial concentration of boron in the aqueous phase severely decreased the boron distribution ratio at low initial concentrations of BEPD in the organic phase. This was caused by the dissolution of BEPD into aqueous solution. The loss of BEPD into the aqueous phase became severe as the concentration of boron in the aqueous phase increased. The loss of EHA was insignificant for all boron concentrations. The distribution ratio of boron was plotted with a function of the equilibrium concentrations of the extractants. The plots showed a linear relation indicating that boron extraction resulted from the same mechanism in all the extraction systems examined in our study. Distribution equations for all the extraction systems were determined.