Mathematical modeling for facilitated transport of Ge(IV) through supported liquid membrane containing Alamine 336

Abstract

A mathematical model was developed for the germanium facilitated transport from a medium containing tartaric acid using Alamine 336 as a carrier. Modeling was carried out based on the extraction constant (K ext) obtained from the liquid-liquid extraction (LLX) modeling. The LLX data was achieved from experiments with conditions being Alamine 336 concentrations of 0.1-10 %v/v from a solution containing about 1.378 mmol/L Ge (100 mg/L) and tartaric acid as an anionic complexant. The LLX model was attained using the equilibrium-based procedure and fitted to extraction experimental data for various carrier concentrations. This model presented an accurate extraction constant (K ext =0.02) used in the facilitated transport modeling. The flat sheet supported liquid membrane (FSSLM) experiments were conducted in the condition of 1.378 mmol/L Ge (100 mg/L), tartaric acid concertation of 2.760 mmol/L, 1 M HCl as a stripping phase and various Alamine 336 concentrations in the range of 0 to 35 %v/v. The FSSLM model was developed according to the Fick's law, the diffusional transport, and equilibrium equations. According to the model, mass transfer and diffusion coefficients for various concentrations of the carrier were found. In addition, the calculated and experimental values had a good correlation with together showing the validity of the model. This model can be used in the further process simulation such as hollow fiber SLMs.

Non-dispersive selective extraction of germanium from fly ash leachates using membrane-based processes

“…[34] In addition, GeðOHÞ 2 ðTÞ 2 2À species are reported to be predominant at neutral pHs. [30,35,36] One of the ways to know the number of extractant molecules that can extract germanium species is the slope analysis. In this regard, the plot of log(D) as a function of log½R 3 NH þ Cl À ðorgÞ was plotted elsewhere.…”

“…In this regard, the plot of log(D) as a function of log½R 3 NH þ Cl À ðorgÞ was plotted elsewhere. [30] The slope of the plot showed that 2 moles of the extractant participated in the extraction reaction. In addition, according to charge balancing and the mentioned slope, the charge of germanium anionic species extracted by Alamine 336 should be 2 as GeðOHÞ 2 ðTÞ 2À orGeðOHÞ 2 ðTÞ 2 2À .…”

“…Only three systems were used to transport germanium through flat sheet supported liquid membranes. In these systems, TOA [29] , Alamine 336 [30] , and Cyanex 301 [31] were used to transport germanium from tartaric acid and nitric acid solutions. In the TOA-SLM system, germanium tartrate was transported from a solution through the polytetrafluoroethylene (PTFE) membrane.…”

“…In a study published by the authors of the present study, mathematical models resulted in calculating the constant (K ext ) of germanium extraction by Alamine 336 and mass transfer and diffusion coefficients for the germanium facilitated transport through the supported liquid membrane containing Alamine 336. [30] In this study, only the Alamine 336 concentration effect was investigated on the extraction and transport of germanium. The principle of the modeling is also founded on this effect.…”

Non-Dispersive Extraction of Ge(IV) from Aqueous Solutions by Cyanex 923: Transport and Modeling Studies

“…Gasification coal fly ashes (GCFAs) containing germanium can be leached with water to dissolve germanium as water-soluble species [5]. Several processes have been developed to recover and separate germanium from impurities such as precipitation [6], flotation [7], ion-exchange [8], distillation [2], adsorption [9], liquid-liquid extraction (LLX) [10], and supported liquid membrane (SLM) [11][12][13]. Among these techniques, the LLX processes have been extensively applied to separate germanium from aqueous solutions [14,15].…”