Synergistic extraction of zine(II) by mixtures of tri-butyl-phosphate and trialkyl amine extractant

The extraction of Zn(2+) by mixtures of tri-butyl-phosphate (TBP, B) and trialkyl amine (N235, R(3) N, R = C(8) similar to C(10)) has been carried out. The mixtures have evident synergistic effects on Zn(2+) with a synergistic enhancement factor of 12. 34. The extraction mechanism was studied using the methods of slope analysis and constant mole. The extracted complex was determined as (R(3)N)(1.5)center dot-ZnCl(2)center dot B. The equilibrium constant and thermodynamic functions Delta H, Delta G and Delta S have been calculated, indicating that the reaction is exothermic driven. The extraction of Zn(2+) and Cd(2+) by the mixtures of TBP and N235 or N, N-di (1-methyl-heptyl) acetamide(N503) was also conducted. Results show that the mixtures of TBP and N235 do not have evident synergistic effects on Cd(2+), while TBP-N503 mixing systems also do not have the synergistic effects on either Zn(2+) or Cd(2+). Moreover, the separation factors of Zn(2+) and Cd(2+) by TBP-N235 system was studied. It is feasible and advantageous to separate Zn(2+) from bulk cadmium solutions.