title: Separation of cobalt and nickel using inner synergistic extraction from bifunctional ionic liquid extractant (Bif-ILE).
abstract: The inner synergistic extraction of [tricaprylmethylammonium][sec-octylphenoxy acetate] ([A336][CA-12]) is studied for cobalt and nickel separation. Distribution ratios of [A336][CA-12] for Co(2+) or Ni(2+) are by far higher than those of tricaprylmethylammonium sulfate ([A336](2)SO(4)), sec-octylphenoxy acetic acid (CA-12), mixture of [A336](2)SO(4) and CA-12 at the acidities from 1x10(-5) mol L(-1) to 1x10(-3) mol L(-1). The synergy coefficients of [A336][CA-12] for Co(2+) are higher than the synergy coefficients of [A336][CA-12] for Ni(2+), which can be used for the Co(2+) and Ni(2+) separation. Some thermodynamic properties of the inner synergistic extraction using [A336][CA-12] for Co(2+) and Ni(2+) are also studied, such as influence of temperature, thermodynamic functions, extraction mechanism, separation factors and stripping properties.
authors.affiliation: State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Remin Street 5625, Changchun 130022, PR China.
authors.forename: Xiaoqi
authors.initials: X
authors.lastname: Sun
authors.forename: Yang
authors.initials: Y
authors.lastname: Ji
authors.forename: Lina
authors.initials: L
authors.lastname: Zhang
authors.forename: Ji
authors.initials: J
authors.lastname: Chen
authors.forename: Deqian
authors.initials: D
authors.lastname: Li
mesh_terms: D003035:Cobalt / Q000302:isolation & purification*; D007477:Ions; D009682:Magnetic Resonance Spectroscopy; D009532:Nickel / Q000302:isolation & purification*
chemical_list: D007477:Ions; D003035:Cobalt; D009532:Nickel