Extraction of lanthanide ions from aqueous solution by modified supercritical CO2: tri-n-butylphosphate plus CO2 and bis-2-ethylhexyl phosphoric acidplus CO2
Sn. Joung et al., Extraction of lanthanide ions from aqueous solution by modified supercritical CO2: tri-n-butylphosphate plus CO2 and bis-2-ethylhexyl phosphoric acidplus CO2, J SUPERCR F, 18(2), 2000, pp. 157-166
High-pressure single-phase limit of binary tri-n-butylphosphate (TBP) + CO2
and bis-2-ethylhexyl phosphoric acid (B2EHPA) + CO2 was measured. By a var
iable-volume view-cell apparatus, the phase transition pressures of each sy
stem were measured at various phase-equilibrium conditions (313.15-333.15 K
, 10-25 MPa. 3.7-18.9 mol% TBP and 1.0-45.0 mol% B2EHPA). Based on this dat
a, supercritical fluid extraction (SFE) was carried out for lanthanide ions
from acidic aqueous solution. In the first place, SFE was carried out for
Nd3+ over a wide range of conditions (0-5 M HNO3, 313.15-333.15 K and 10-25
MPa) and optimum SFE process conditions are evaluated. In the second place
, SFE was carried out at 313.15 K and 25 MPa for six types of lanthanide io
ns (La3+, Ce3+, Nd3+, Sm3+, Eu3+, and Yb3+) from 1 M HNO3 acidic solution a
nd the characteristics of different metals on the SFE were compared. (C) 20
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