Solvent formulation is important in the optimization of the mass-transfer through supported liquid membranes (SLM) in pertraction and membrane extraction. Oleyl alcohol (OA) is frequently used as the solvent or diluent in the extraction of carboxylic acids. A disadvantage of OA is its relatively high viscosity of 28.32 mPa s at 25°C. This can be decreased by the application of a less viscous OA diluent, e.g. dodecane. The relationship between the ratio of the distribution coefficient of butyric acid (BA), D F, and the viscosity of OA-dodecane solvents, µ, as extraction and transport characteristics, and the overall mass-transfer coefficient, K p, through SLMs was analyzed. Dependence of the D F/µ ratio on the OA concentration showed a maximum at the OA concentration of 15 mass % to 30 mass %. The OA concentration dependence of K p for SLMs exhibited also a maximum at about 30 mass % and 20 mass % of OA at the BA concentration driving force of 0.12 kmol m−3 and 0.3 kmol m−3, respectively. Shifting of the maximum in K p dependences towards lower OA concentrations by increasing the BA concentration driving force is in agreement with the D F/µ ratio dependence. Using pure OA as the solvent or diluent is not preferable and a mixture of a low viscosity diluent with the OA concentration below 40 mass % should be used. The presented results show the potential of the D F/µ ratio in the screening and formulation of solvents in extraction and SLM optimization.
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机译：溶剂配方对于优化在吸附和膜萃取过程中通过支持液膜（SLM）的传质至关重要。油酸（OA）在羧酸萃取中经常用作溶剂或稀释剂。 OA的一个缺点是它在25°C时相对较高的粘度为28.32 mPa s。可以通过使用粘度较小的OA稀释剂（例如十二烷。分析了丁酸（BA）的分配系数（DF）与OA-十二烷溶剂的粘度（μ）的比（作为萃取和传输特性）与通过SLM的总传质系数（K p）之间的关系。 D F /μ比与OA浓度的关系在OA浓度为15质量％至30质量％时显示出最大值。在BA浓度驱动力分别为0.12 kmol m-3和0.3 kmol m-3的情况下，K p对SLM的OA浓度依赖性在OA的约30质量％和20质量％时也表现出最大值。通过增加BA浓度驱动力，最大的K p依赖性向较低的OA浓度的移动与D F /μ比率依赖性相关。使用纯OA作为溶剂或稀释剂不是优选的，并且应使用OA浓度低于40质量％的低粘度稀释剂的混合物。给出的结果表明，在萃取和SLM优化中筛选和配制溶剂时D /μ比的潜力。
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