Phase extraction separation of platinum with n-propanol-potassium thiocyanate-sodium chloride-water system
LI Yu-ling1,SI Xue-zhi2,MA Dong-dong1, MA Wan-shan*1
1.College of Chemistry and Chemical Engineering, Xinyang Normal University, Xinyang 464000, China; 2.College of Chemistry and Chemical Engineering,Henan University of Technology, Zhengzhou 450052, China
Abstract：The behavior and conditions for phase extraction separation of platinum from other metal ions in n-propanol-potassium thiocyanate-sodium chloride-water system were investigated. The results showed that the aqueous solution of n-propanol could be divided into two phases with the effect of sodium chloride, and in the phase separation process, the [Pt(SCN)6]2- formed by Pt(Ⅳ) and potassium thiocyanate reached with protonated [PrOH2]+ to form [Pt(SCN)6]2-·2 [PrOH2]+ ionic associate which could be completely extracted with n-propanol phase. When the concentrations of n-propanol, potassium thiocyanate and sodium chloride in the solution were 30%(V/V), 6.0×10-2 mol/L and 0.16 g/mL, respectively. The extraction yield of Pt(Ⅳ) was more than 98.2%. Mo(Ⅵ)、Ce(Ⅲ)、Ni(Ⅱ)、V(Ⅴ)、Cr(Ⅲ)、Ag(Ⅰ)、Mn(Ⅱ)、Mg(Ⅱ)、Cd(Ⅱ)、Ga(Ⅲ)、Fe(Ⅱ) and Al(Ⅲ) in the solution could not be extracted, realizing the separation of Pt(Ⅳ) from these metal ions. The method has been applied to the extraction separation and determination of platinum in the sample of Ni-Pt/Al2O3 catalyst, and the results were consist with reference values with the relative standard deviation(RSD,n=5) of 2.3%.
