A mathematical model was developed to monitor the facilitated transport of germanium(IV) from oxalic acid solutions through a flat sheet supported liquid membrane(FSSLM) containing four trialkylphosphine oxides(Cyanex...A mathematical model was developed to monitor the facilitated transport of germanium(IV) from oxalic acid solutions through a flat sheet supported liquid membrane(FSSLM) containing four trialkylphosphine oxides(Cyanex 923). The FSSLM modeling was based on the extraction constant(Kext) calculated from the liquid-liquid extraction(LLX) modeling. The LLX model presented a reliable calculation of the extraction constant(Kex= 2.057×103 L/mol4). The FSSLM model was solved using Matlab■ software according to extraction constant, Fick’s law, and diffusional principles. The model predicts the overall mass transfer coefficient(Korg) to be 3.84 cm/s. Using this value, diffusion coefficients(Dm) for various Cyanex 923 concentrations of 0.126, 0.252, 0.378, 0.505, 0.631 and 0.757 mol/L are found to be 8.50×10^-4, 4.30×10^-4, 1.87×10^-4, 5.87×10^-5, 2.57×10^-5, 2.09×10^-5 cm2/s, respectively. The results show that the diffusion rate of the current study is approximately more than that of similar FSSLM systems containing Cyanex 923 used to transport various metals. The modeling values are in good agreement with the experimental data, showing the good reliability of the mathematical model.展开更多
In this study,a polyamide with methine-thiophene and pyrimidine linkages(poly(pyrimidine-thiophene-amide)(PPTA))was synthesized.Then,magnetic PPTA(M-PPTA)was synthesized using the hydrothermal technique.The products w...In this study,a polyamide with methine-thiophene and pyrimidine linkages(poly(pyrimidine-thiophene-amide)(PPTA))was synthesized.Then,magnetic PPTA(M-PPTA)was synthesized using the hydrothermal technique.The products were analyzed by Fourier-transform infrared spectroscopy(FTIR),nuclear magnetic resonance(NMR),X-ray diffraction(XRD),thermogravimetric analysis(TGA),field-emission scanning electron microscopy(FE-SEM),and a vibrating-sample magnetometer(VSM).The nanocomposite exhibits a saturation magnetization of 50.44 emu/g recorded by VSM analysis.The ability of M-PPTA to bind dysprosium(Dy^(3+)),terbium(Tb^(3+)),and neodymium(Nd^(3+))was investigated.Using 0.15 g of M-PPTA to test the adsorption of the rare earth elements(50 mg/L)at pH=5.5,the percentage of adsorption for Dy^(3+),Tb^(3+),and Nd^(3+)is 98.41%,97.48%and 95.67%,respectively.Pseudo-second-order(PSO)significantly fits the adsorption kinetic data.Freundlich equation was used to describe the adsorption equilibrium data of Dy^(3+)and Tb^(3+),while Langmuir model was used to simulate Nd^(3+)adsorption data.Increasing the temperature leads to an increase in the performance of M-PPTA,and an endothermic adsorption process was confirmed by the positive values ofΔH.After four adsorption-desorption cycles,the efficiency of adsorption of Dy^(3+),Tb^(3+),and Nd^(3+)by M-PPTA is88.75%,86.37%,and 84.64%,respectively.An antagonism effect is observed for the adsorption of the individual ions in a ternary solution.展开更多
文摘A mathematical model was developed to monitor the facilitated transport of germanium(IV) from oxalic acid solutions through a flat sheet supported liquid membrane(FSSLM) containing four trialkylphosphine oxides(Cyanex 923). The FSSLM modeling was based on the extraction constant(Kext) calculated from the liquid-liquid extraction(LLX) modeling. The LLX model presented a reliable calculation of the extraction constant(Kex= 2.057×103 L/mol4). The FSSLM model was solved using Matlab■ software according to extraction constant, Fick’s law, and diffusional principles. The model predicts the overall mass transfer coefficient(Korg) to be 3.84 cm/s. Using this value, diffusion coefficients(Dm) for various Cyanex 923 concentrations of 0.126, 0.252, 0.378, 0.505, 0.631 and 0.757 mol/L are found to be 8.50×10^-4, 4.30×10^-4, 1.87×10^-4, 5.87×10^-5, 2.57×10^-5, 2.09×10^-5 cm2/s, respectively. The results show that the diffusion rate of the current study is approximately more than that of similar FSSLM systems containing Cyanex 923 used to transport various metals. The modeling values are in good agreement with the experimental data, showing the good reliability of the mathematical model.
基金Project supported by the Spanish Ministry of Economy and Competitiveness (CTM2017-83581-R)。
文摘In this study,a polyamide with methine-thiophene and pyrimidine linkages(poly(pyrimidine-thiophene-amide)(PPTA))was synthesized.Then,magnetic PPTA(M-PPTA)was synthesized using the hydrothermal technique.The products were analyzed by Fourier-transform infrared spectroscopy(FTIR),nuclear magnetic resonance(NMR),X-ray diffraction(XRD),thermogravimetric analysis(TGA),field-emission scanning electron microscopy(FE-SEM),and a vibrating-sample magnetometer(VSM).The nanocomposite exhibits a saturation magnetization of 50.44 emu/g recorded by VSM analysis.The ability of M-PPTA to bind dysprosium(Dy^(3+)),terbium(Tb^(3+)),and neodymium(Nd^(3+))was investigated.Using 0.15 g of M-PPTA to test the adsorption of the rare earth elements(50 mg/L)at pH=5.5,the percentage of adsorption for Dy^(3+),Tb^(3+),and Nd^(3+)is 98.41%,97.48%and 95.67%,respectively.Pseudo-second-order(PSO)significantly fits the adsorption kinetic data.Freundlich equation was used to describe the adsorption equilibrium data of Dy^(3+)and Tb^(3+),while Langmuir model was used to simulate Nd^(3+)adsorption data.Increasing the temperature leads to an increase in the performance of M-PPTA,and an endothermic adsorption process was confirmed by the positive values ofΔH.After four adsorption-desorption cycles,the efficiency of adsorption of Dy^(3+),Tb^(3+),and Nd^(3+)by M-PPTA is88.75%,86.37%,and 84.64%,respectively.An antagonism effect is observed for the adsorption of the individual ions in a ternary solution.
