| Recently,gemini type amphiphilic ionic liquids has attracted attentions because of their excellent surface activity,rich self-assembly behavior and received extensive.Self-assembly system also has faster extraction rate and higher extraction efficiency compared with traditional solvent extraction system,and becomes a research hotspot in the field of extraction.In this paper,we first studied the[C14-n-C14im]Br2(n = 2,4,6)in microemulsion self-assembly system extraction in HCl medium extraction behavior of Au(III).In the microemulsion[C14-n-C14im]Br2 play the double role of surfactant and extraction agent.In the study of extraction factors(volume ratio of microemulsion and water,extractant concentration,alcohol volume fraction,hydrochloric acid concentration)we found extraction efficiency increased with the number of n(spacer length).Under appropriate conditions,extraction efficiency can reach more than 99%.Then through continuous transformation method,UV-vis,FT-IR,1H-NMR spectra to determine the extraction mechanism of anion exchange which is one[C14-n-C14im]Br2 combining two[AuC14]-.We explain the difference of extractability which caused by spacer length though space steric hindrance and ionization degree of[C14-n-C14im]Br2 in microemulsion system.Moreover,the thermodynamic parameters of extraction process also provides these explanations for more support.Finally using oxalic acid to reverse extraction,extraction rate were above 90%.In order to get quantitative interpretation and provide theoretical basis for industrial practice,we design the dynamics research plan.Kinetic study of[C14-n-C14im]Br2 based microemulsion system was performed by method of rising droplets.To calculate the three extraction solvent extraction of Au(?)in the process of reaction activation energy(in the order n = 2,4,6)were 4.37 kJ mol-1,4.00 kJ·mol-1,3.96 kJ·mol-1.This result demonstrates that the diffusion process is the control step,and when the spacer length gets longer the energy barriers to“overcome”would be lower.Then we calculated the mass transfer coefficient and the dynamic equations,which shows that the mass-transfer would be faster if the spacer length gets longer.Through the calculation of dynamic equation of extraction process of mass transfer and mass transfer coefficient,parameters,we provide more intuitionistic explain for the phenomenon that extraction efficiency increased with spacer length.At the same time,research results can provide important theoretical basis for industrial production.Finally in order to further expand[C14-n-C14im]Br2 application,and build more green,no organic solvent extraction system,we design the[C14-n-C14im]Br2/SDC(hereinafter referred to as 14-n-14/SDC)vesicle system used in the extraction of Au(?).We pass the test before and after the extraction of the zeta potential and particle size of vesicle,combined with TEM photographs identified the vesicle and Au(?)the electrostatic attraction between the action principles.Then we found 14-n-14/SDC vesicle has more excellent extractability compared with pure 14-n-14 vesicle.After comparing the diameter change of two vesicles under the influence of NaCl and NaBr,we found that 14-n-14/SDC vesicle was very stable.Furthermore,the increase of spacer length can strengthen the stability of the vesicles,and the 14-6-14/SDC vesicle also showed a better extraction ability and anti-interference. |
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