Application of hydrophobic extractant in aqueous two-phase systems for selective extraction of cobalt, nickel and cadmium.
This work developed a new and efficient method of extracting and separating Co(II), Ni(II) and Cd(II) in aqueous two-phase systems (ATPS) composed of triblock copolymer (L64)+Na(2)C(4)H(4)O(6)+water and L64+Li(2)SO(4)+water using the hydrophobic extractant 1-nitroso-2-naphtol, which complexes the metal ions and partitions in the triblock copolymer micelles in the ATPS top phase. Metal extraction from the salt-rich phase to the copolymer - rich phase is strongly affected by the fine-tuning of the following parameters: amount of added extractant, type of electrolyte, pH, and tie-line length. Excellent separation factors (S(i,j)) between the metals were obtained at pH=3.00 (S(Co,Cd)=1550 and S(Ni,Cd)=16,700) and pH=1.00 (S(Co,Ni)=826). In the interference study, Co(II) was selectivity extracted in the top phase in the presence of Ni(II) and Cd(II) in a concentration of up to 20 times the cobalt level in the system.
Grupo de Química Verde Coloidal e Macromolecular, Departamento de Química, Centro de Ciências Exatas e Tecnológicas, Universidade Federal de Viçosa, Av. P.H. Rolfs s/n, Viçosa, MG 36560-000, Brazil.
Guilherme Dias
GD
Rodrigues
Leandro Rodrigues
LR
de Lemos
Luis Henrique Mendes
LH
da Silva
Maria C Hespanhol
MC
da Silva
D002104:Cadmium / Q000737:chemistry / Q000302:isolation & purification*; D003035:Cobalt / Q000737:chemistry / Q000302:isolation & purification*; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D059625:Liquid-Liquid Extraction / Q000379:methods*; D009532:Nickel / Q000737:chemistry / Q000302:isolation & purification*
D002104:Cadmium; D003035:Cobalt; D009532:Nickel