Extraction And Separation Of Metal Ions Inhydrochloric Acid Medium By Quaternary Salt Ionic Liquid

In the past ten years,ionic liquids have been gradually applied in various fields such as electrochemical catalysis due to their excellent properties,and they also play an indispensable role in liquid-liquid extraction.Among a series of compounds of ionic liquids,nitrogen and phosphorus are the main components,meanwhile the research and application are relatively more abundant.Hundreds of imidazole and quaternary ammonium salt-type compounds have been reported,so on this basis our could further research will be conducted to explore ionic liquids with other functional groups based on quaternary ammonium salts.In this thesis,several new ionic liquids with amide structure based on quaternary ammonium salts are used to construct the extraction system under the hydrochloric acid system,which is used for noble metals Au(Ⅲ),as well as Pd(Ⅱ),Pt(Ⅳ),Rh(Ⅲ)and the separation of transition metal Cr(Ⅵ)/V(Ⅴ).Firstly,a new type of amide ionic liquid was designed and synthesized,and a liquid-liquid extraction system of chloroform in hydrochloric acid medium was constructed for the separation of Au(Ⅲ)from secondary resources.Through the optimization of a series of different factors such as temperature,acidity,salinity,etc.,Au(Ⅲ)extraction rate of 96.1%and distribution ratio of 96 can be achieved.At the same time,in the environment where various noble metals and transition metal ions coexist,the extraction rate of Au(Ⅲ)can still reach 92.1%and 93.0%with excellent selectivity.In addition,the extraction mechanism of anion exchange was determined by job method and carbon NMR spectroscopy combined with spectroscopic characterization.Afterwards,acidic thiourea was selected to achieve efficient stripping of Au(Ⅲ)in the loaded organic phase,and the cycle performance test of the system proved that the extraction effect of the extractant did not decrease significantly during the 4 cycles.The thermodynamic data showed the spontaneity of the reaction and the stability of the extract,and the kinetic data were in good agreement with the pseudo-second-order kinetic model.Finally,the extraction isotherm and the corresponding McCabe-Thiele plot were used to predict the theoretical countercurrent extraction stage compared with the experiment,and then the prediction was simulated and verified.In conclusion,the efficient separation and recovery of Au(Ⅲ)was realized.Then a new long-chain alkane-based amide ionic liquid was designed and synthesized,which realized the separation of Pd(Ⅱ),Pt(Ⅳ),Rh(Ⅲ)in secondary resources.Firstly,the influence of factors such as the amount of extractant,acidity and temperature was explored,and the extraction conditions were optimized.In addition,the extraction mechanism of anion exchange was determined by job method combined with spectroscopic characterization.In the environment where various noble metals and transition metal ions coexist,the extraction rates of Pd(Ⅱ)and Pt(Ⅳ)are over 95%,and have excellent selectivity.Afterwards,acidic potassium thiocyanate and thiourea were selected to achieve efficient stripping of Pd(Ⅱ)and Pt(Ⅳ)in the loaded organic phase.At the same time,the test proved that the extraction efficiency was not significantly decreased on the extraction during 4 cycles.In the experiment,the kinetics are in good agreement with the pseudo-second-order kinetics.Finally,the separation process of Pd(Ⅱ),Pt(Ⅳ)and Rh(Ⅲ)under the catalyst components was simulated,and the efficient separation and recovery of the three precious metals were realized.Finally,utilize the above-mentioned long-chain alkane quaternary ammonium salt amide ionic liquid,its application in the separation of transition metals was expanded,and the separation of Cr(Ⅵ)and V(Ⅴ)was realized.Firstly,the influence of factors such as pH,coexisting anions and temperature in the extraction was explored,and the extraction conditions were optimized,and the extraction rates of Cr(Ⅵ)and V(Ⅴ)could reach 98.1%and 97.4%.In addition,the extraction mechanism of anion exchange was determined by saturation load method combined with spectroscopic characterization.Then,Sodium bisulfite and and mixed solution of sodium hydroxide and sodium chloride were selected to realize the efficient stripping of Cr(Ⅵ)and V(Ⅴ)in the supported organic phase.The extraction rate of V(Ⅴ)are over 95%in polymetallic mixed solution and the test proves that the extraction effect of the extractant does not decrease significantly during 4 cycles.Combining the kinetic data with the fitting of the two models,it is shown that for Cr(Ⅵ),V(Ⅴ)fits the second-order kinetic models.Finally,the separation process of Cr(Ⅵ)and V(Ⅴ)in the Cr(Ⅵ),V(Ⅴ)slag leaching solution was simulated,and the efficient separation and recovery of the two were realized.