Novel Technique of Separation and Purification of Palladium with Liquid Membrane

1.为了阐明十二烷基单硫代磷酸萃取钯的机理，在高搅拌槽和搅拌传送池中进行了萃取。还进行了萃取剂负载钯的实验和萃取剂界面张力的测定。考察了萃取率与浓度的关系，建立了四种氯钯络合物参与萃取反应的界面反应模型。根据模型对萃取率进行分析，得到了各氯钯络合物与吸附在界面上的萃取剂之间的界面反应速率常数。讨论了硫氰酸根离子在上述体系中对萃取率的影响。硫氰酸根离子的加入使萃取率提高了600倍。对实验结果进行了分析，考虑了三种…之间的界面反应。氯代硫氰基-钯络合物和萃取剂在界面上吸附的取代基数较多。为了考察萃取剂的烷基链长对萃取率的影响，测定了二正辛基一硫代磷酸对钯的萃取率。按上述相同机理分析萃取率得到的界面反应速率常数略大于十二烷基硫代磷酸。采用液体表面活性剂膜萃取钯。以硫脲为反萃剂，首次测定了二正辛基一硫代磷酸-钯络合物的反萃平衡，得到了反萃平衡常数。然后在搅拌转移池中测量了钯的反萃率，并考察了反萃率的浓度依赖性。最后进行了液膜萃取钯的实验，发现钯在液膜中的渗透机理尚不清楚。这一点还需要进一步研究。较少

1. To elucidate the mechanism of solvent extraction of palladium with didodecylmonothiophosphoric Acid, the extraction was carried out in a highly stirred tank or in a stirred transfer cell. Loading test of palladium with the extractant and measurement of interfacial tension of the extractant were also conducted. Concentration dependencies of the extraction rate were examined, from which an interfacial reaction model where four kinds of chloro-palladium complexes participate in the extraction reaction was presented. As the result of analyzing the extraction rate based on the model, the interfacial reaction rate constants between each chloro-palladium complex and the extractant adsorbed at the interface were obtained.2. Trans-effect of thiocyanate ion on the extraction rate in the above-mentioned system was discussed. An addition of thiocyanate ion enhanced the extraction rate by 600 times. The experimental results were analyzed by considering the interfacial reactions between three kin … More ds of chloro-thiocyano-palladium complexes and the extractant adsorbed at the interface.3. To examine alkyl-chain length of the extractant on the extraction rate, the extraction rate of palladium with dioctylmonothiophosphoric acid was measured. The interfacial reaction rate constants obtained from analyzing the extraction rate based on the same mechanism as mentioned above were somewhat greater than those of didodecylmonothiophosphoric acid.4. Extraction of palladium with liquid surfactant membrane was carried out. First stripping equilibrium of dioctylmonothiophosphoric acid - palladium complex was measured by using thiourea as the stripping agent, and the stripping equilibrium constant was obtained. Then the stripping rate of palladium was measured in the stirred transfer cell, and the concentration dependencies of the rate were examined. Lastly the extraction of palladium with liquid surfactant membrane was conducted, from which it was found that a permeation mechanism of palladium through the liquid membrane was difficult to be clarified. Further study on this point will be necessary. Less