چكيده به لاتين
In the present study, extraction of gold(III) from an acidic medium was performed using 1-butyl-3-methylimidazolium hexafluoroPhosPhate ([bmim][PF6]) at 25 °C for which the thermodynamic modeling was investigated. In the first step, the extraction capability of 1-butyl-3-methylimidazolium hexafluoroPhosPhate known as [BMIM] [PF6] and 1-octanol mixture, as an organic solvent in separation of Au(III). The influence of initial ion concentration, 1-butyl-3-methylimidazolium hexafluoroPhosPhate concentration, acidity of solution, volumetric ratio of aqueous to organic phase, and extraction time are examined. Central composite design in response-surface methodology was applied for the optimization of the effective parameters and the number of required experiments. The results confirmed that using the mixture of IL and organic solvent not only presents a great potential in extraction of gold(III) with high efficiency but also has several other advantages. This process is rapid, simple, environmentally benign, low cost, affordable, and consumes less organic solvent.
In the theorical part of present study, not only 0.1 M aqueous hydrochloric acid media contained [bmim][PF6] was experimentally applied to the extraction of gold(III), but also the engineering version of Statistical Associating Fluid Theory (SAFT) Equationof State (EoS), introduced byHuang and Radosz (SAFT-HR EoS) coupled with the implicit version of mean sPherical approximation model (MSA) was applied for thermodynamic modelingof the equilibrium system. Non-idealities of both aqueous and organic phases were taken into account. A set of EoS parameters for each component was obtained by fitting to reliable experimental density/ activity coefficient data from literature. The gold compelex parameters are obtained through mass and charge balances along with the chemical equilibrium constants relations. The theory is found to accurately model the extraction efficiency of gold(III) with the average error of 0.085%. The predictive capability of the model was studied, as well. The results show that the model is a powerful tool for modeling the extraction system containing water, ions and IL.
