Study On Transfer Behavior Of Pt(Ⅳ) And Pd(Ⅱ) Through Supported Liquid Membrane

Noble metals have unique physical and chemical properties,so they have a wide range of industrial applications.But because their physical and chemical properties are very similar,also their valences are changeful and the same noble metal ion with different valences have different properties,so it's a challenging task to separate the noble metals.The liquid membrane separation technology has the advantages of combination of extraction and back extraction,higher mass transportation speed and throughput,higher selectivity,better separation efficiency and concentration ratio,easy to operate.It's a new separation technology studied extensively in recent years.In order to improve the selectivity and practicability of separation of noble metals,the application of liquid membrane technology to separate noble metals has been studied and good progress has been made by a lot of researchers.however,the separation of noble metals through emulsion liquid membrane has been reported more than that of supported liquid membrane.Therefore,on the basis of solvent extraction,the transfer behaviors of Pt(â…£) and Pd(â…¡)through supported liquid membrane have been studied systemically in the paper.The results are as follows:1.The extraction equilibrium of Pt(â…£)and Pd(â…¡)The experiments have been carried out with various extractants.The conditions of extraction and back extraction have been discussed,and the optimum extraction conditions are obtained.(1)The extraction equilibrium experiment of Pt(â…£)When the initial concentration of Pt(â…£)in the aqueous phase is 5.0μg/mL,SnCl₂ concentration is 0.05mol/L,HCl concentration is 0.50mol/L,kerosene as diluent in the organic phase,2-ethylhexylphosphonic acid mono-2-ethylhexyl ester(P₅₀₇)concentration is 5.0%(w/V),the volume ratio of aquous phase and organic phase is 1:1,oscillation 30 minutes,the extraction rate of Pt(â…£)is nearly 100%,the stripping agent is the same volume of 4mol/L HCl,the strip percentage is above 99%.(2)The extraction equilibrium experiment of Pd(â…¡)When the initial concentration of Pd(â…¡)in the aqueous phase is 6.754μg/mL,HCl concentration is 0.50mol/L,kerosene as diluent in the organic phase,N,N-di(methyl-heptyl)acetaminde(N₅₀₃)concentration is 10.0%(w/V),the volume ratio of aquous phase and organic phase is 1:1,oscillation 30 minutes,the extraction rate of Pd(â…¡)is 99.2%,the stripping agent is the same volume of 0.2mol/L KSCN,the strip percentage is above 95%.2.The transport of Pt(â…£)and Pd(â…¡)through supported liquid membraneThe transfer behaviors of Pt(â…£)and Pd(â…¡)through a supported liquid membrane consisting of P₅₀₇or N₅₀₃solution in kerosene,adsorbed on a hydrophobic Polyvinylidene Fluoride microporous film have been studied respectively.(1)The transport experiment of Pt(â…£)The concentration ofPt(â…£)1.0μg/mL has been chosen as initial concentration,the effects of HCl and SnCl₂ concentration in the feed phase,P₅₀₇concentration in the membrane phase,HCl concentration in the strip phase on the transport of Pt(â…£)have been discussed,and the best transport conditions of Pt(â…£)are obtained:When initial concentration of Pt(â…£)is 1.0μg/mL,SnCl₂ concentration is 0.05mol/L and HCl concentration is 1.0mol/L in the feed phase,P₅₀₇concentration in the membrane phase is 5.0%(w/V),HCl concentration in the strip phase is 6.0mol/L,the transport rate is nearly 100%in three hours.(2)The transport experiment of Pd(â…¡)The concentration of Pd(â…¡)3.0μg/mL has been chosen as initial concentration,the effects of HCl concentration in the feed phase,N₅₀₃concentration in the membrane phase,KSCN concentration in the strip phase on the transport of Pd(â…¡)have been discussed,and the best transport conditions of Pd(â…¡)are obtained:When initial concentration of Pd(â…¡)is 3.0μg/mL and HCl concentration is 0.2mol/L in the feed phase,N₅₀₃concentration in the membrane phase is 10.0%(w/V),KSCN concentration in the strip phase is 0.2mol/L,the transport rate is above 93%in four hours.3.Simulation experimentsOn the basis of Pt(â…£)transport through the supported liquid membrane using P₅₀₇as a mobile carrier,the separation of Pt(â…£)and several transition metal ions have been studied.(1)Separation experiments of two metal ionsUnder the best conditions of transport Pt(â…£),1.0μg/mL Pt(â…£)can separate from 50μg/mLNi(â…¡),100μg/mLCo(â…¡),100μg/mL Cu(â…¡)and 150μg/mLZn(â…¡)respectively.The transport rates of Pt(â…£)are 89%,86%,81%and 87%,respectively in three hours.The mutual separation of Pt(â…£)and Ni(â…¡),Pt(â…£)and Co(â…¡),Pt(â…£)and Cu(â…¡),Pt(â…£)and Zn(â…¡),has been basically achieved.(2)The separation experiment of simulated platinum plating solutionSimulated platinum plating solution consisting of 0.8μg/mLPt(â…£),75μg/mLCu(â…¡), 75μg/mLZn(â…¡),75μg/mL Co(â…¡),75μg/mLNi(â…¡),75μg/mLSO₄^2-is treated through the supported liquid membrane system which has been established above,the transport rate of Pt(â…£) is 87.8%in three hours,other metal ions do not transport.The results showed that the separation method of Pt(â…£)through SLM established in this paper has certain value of reference and application.