The extraction kinetics of Ce（Ⅳ） and Ce（Ⅳ）-F^- mixture systems from sulfuric solutions to n-heptane solution containing Bif-ILE[A336][P204]（[trialkylmethylammonium][di-2-ethylhewanxylphosphinate]） with a const...The extraction kinetics of Ce（Ⅳ） and Ce（Ⅳ）-F^- mixture systems from sulfuric solutions to n-heptane solution containing Bif-ILE[A336][P204]（[trialkylmethylammonium][di-2-ethylhewanxylphosphinate]） with a constant interfacial area cell with laminar flow were studied,just to elucidate the extraction mechanism and the mass transfer models.The data were analyzed in terms of pseudo-first-order constants.The effects of stirring speed,specific interfacial area and temperature on the extraction rate in both systems were discussed,suggesting that the extractions were mixed bulk phases-interfacial control process.Supported by the experimental data,the corresponding rate equations for Ce（Ⅳ） extraction system and Ce（Ⅳ）-F^- mixture extraction system were obtained.The experimental results indicated the rate-controlling step.The kinetics model was deduced from the rate-controlling step and consistent with the rate equation.展开更多
本文采用溶剂热法合成了微孔结构的锆基金属-有机框架(MOFs)材料Zr-CAU-24,该材料比表面积为1610 m 2/g。对所合成的Zr-CAU-24进行了热重分析(TGA)和辐照稳定性测试,考察了接触时间、初始pH值等对Zr-CAU-24对Th(Ⅳ)和Ce(Ⅳ)吸附性能的影...本文采用溶剂热法合成了微孔结构的锆基金属-有机框架(MOFs)材料Zr-CAU-24,该材料比表面积为1610 m 2/g。对所合成的Zr-CAU-24进行了热重分析(TGA)和辐照稳定性测试,考察了接触时间、初始pH值等对Zr-CAU-24对Th(Ⅳ)和Ce(Ⅳ)吸附性能的影响,并探讨了Zr-CAU-24对Th(Ⅳ)和Ce(Ⅳ)吸附过程的动力学和热力学。结果表明:Zr-CAU-24具有良好的热稳定性和辐照稳定性;准二级动力学模型为Th(Ⅳ)和Ce(Ⅳ)在Zr-CAU-24上的吸附过程提供了很好的解释,即该过程为化学吸附过程;Zr-CAU-24活性位点分布均匀,为单层吸附;混合金属离子溶液吸附研究发现,Zr-CAU-24对Th(Ⅳ)和Ce(Ⅳ)具有吸附选择性。展开更多
The solvent extinction behavior Of Th(Ⅳ) and Ce(Ⅳ) with Cyanex 925 in nhexane hem nitric acid medium was studied. The extinction mechanisms of Th(Ⅳ)and Ce(Ⅵ) by Cyanex 923 were determined by the method of slope an...The solvent extinction behavior Of Th(Ⅳ) and Ce(Ⅳ) with Cyanex 925 in nhexane hem nitric acid medium was studied. The extinction mechanisms of Th(Ⅳ)and Ce(Ⅵ) by Cyanex 923 were determined by the method of slope analysis, and the extracted species might be Th(NO3)4.S(Cyanex 923)(o) and Ce(NO3)4.2(Cyanex 923)(o). The extraction characteristics with purified Cyanex 925 and commercial Cyanex 925 were compared. Results showed Ce(Ⅳ) and Th(Ⅳ) could be separted with Cyanex 923 hem RE(Ⅲ) in nitric acid solution. The influence of temperature on the Th(Ⅳ) extinction was investigated and the thermodynamic functions were calculated.展开更多
The kinetics and mechanism of lactic acid oxidation in the presence of Mn(II)and Ce(IV)ions by chromic acid were studied spectrophotometrically.The oxidation of lactic acid by Cr(VI)was found to proceed in two measura...The kinetics and mechanism of lactic acid oxidation in the presence of Mn(II)and Ce(IV)ions by chromic acid were studied spectrophotometrically.The oxidation of lactic acid by Cr(VI)was found to proceed in two measurable steps,both of which gave pyruvic acid as the primary product in the absence of Mn(II).2Cr(VI)+2CH3CHOHCOOH→2CH3COCOOH+Cr(V)+Cr(III)Cr(V)+CH3CHOHCOOH→Cr(III)+CH3COCOOH The observed kinetics was explained due to the catalytic and inhibitory effects of Mn(II)and Ce(IV)on the lactic acid oxidation by Cr(VI).The reactivity of lactic acid depends upon the experimental conditions.It acts as a two-or three-equivalent reducing agent in the absence or presence of Mn(II).It was examined that Cr(III)products resulting from the direct reduction of Cr(VI)by three-equivalent reducing agents.The oxidation of lactic acid follows the complex order kinetics with respect to [lactic acid].The activation parameters Ea,ΔH#,and ΔS# were calculated and discussed.展开更多
基金Project (2012CBA01202) supported by the National Basic Research Program of ChinaProject (51174184) supported by the National Natural Science Foundation of China+2 种基金Project (KGZD-EW-201-1) supported by the Key Research Program of the Chinese Academy of SciencesProject (BK2013030) supported by Science and Technology Plan of Nantong City,ChinaProject (RERU2014016) supported by Open Subject of Changchun Institute of Applied Chemistry,Chinese Academy of Sciences,China
文摘The extraction kinetics of Ce（Ⅳ） and Ce（Ⅳ）-F^- mixture systems from sulfuric solutions to n-heptane solution containing Bif-ILE[A336][P204]（[trialkylmethylammonium][di-2-ethylhewanxylphosphinate]） with a constant interfacial area cell with laminar flow were studied,just to elucidate the extraction mechanism and the mass transfer models.The data were analyzed in terms of pseudo-first-order constants.The effects of stirring speed,specific interfacial area and temperature on the extraction rate in both systems were discussed,suggesting that the extractions were mixed bulk phases-interfacial control process.Supported by the experimental data,the corresponding rate equations for Ce（Ⅳ） extraction system and Ce（Ⅳ）-F^- mixture extraction system were obtained.The experimental results indicated the rate-controlling step.The kinetics model was deduced from the rate-controlling step and consistent with the rate equation.
文摘本文采用溶剂热法合成了微孔结构的锆基金属-有机框架(MOFs)材料Zr-CAU-24,该材料比表面积为1610 m 2/g。对所合成的Zr-CAU-24进行了热重分析(TGA)和辐照稳定性测试,考察了接触时间、初始pH值等对Zr-CAU-24对Th(Ⅳ)和Ce(Ⅳ)吸附性能的影响,并探讨了Zr-CAU-24对Th(Ⅳ)和Ce(Ⅳ)吸附过程的动力学和热力学。结果表明:Zr-CAU-24具有良好的热稳定性和辐照稳定性;准二级动力学模型为Th(Ⅳ)和Ce(Ⅳ)在Zr-CAU-24上的吸附过程提供了很好的解释,即该过程为化学吸附过程;Zr-CAU-24活性位点分布均匀,为单层吸附;混合金属离子溶液吸附研究发现,Zr-CAU-24对Th(Ⅳ)和Ce(Ⅳ)具有吸附选择性。
文摘The solvent extinction behavior Of Th(Ⅳ) and Ce(Ⅳ) with Cyanex 925 in nhexane hem nitric acid medium was studied. The extinction mechanisms of Th(Ⅳ)and Ce(Ⅵ) by Cyanex 923 were determined by the method of slope analysis, and the extracted species might be Th(NO3)4.S(Cyanex 923)(o) and Ce(NO3)4.2(Cyanex 923)(o). The extraction characteristics with purified Cyanex 925 and commercial Cyanex 925 were compared. Results showed Ce(Ⅳ) and Th(Ⅳ) could be separted with Cyanex 923 hem RE(Ⅲ) in nitric acid solution. The influence of temperature on the Th(Ⅳ) extinction was investigated and the thermodynamic functions were calculated.
文摘The kinetics and mechanism of lactic acid oxidation in the presence of Mn(II)and Ce(IV)ions by chromic acid were studied spectrophotometrically.The oxidation of lactic acid by Cr(VI)was found to proceed in two measurable steps,both of which gave pyruvic acid as the primary product in the absence of Mn(II).2Cr(VI)+2CH3CHOHCOOH→2CH3COCOOH+Cr(V)+Cr(III)Cr(V)+CH3CHOHCOOH→Cr(III)+CH3COCOOH The observed kinetics was explained due to the catalytic and inhibitory effects of Mn(II)and Ce(IV)on the lactic acid oxidation by Cr(VI).The reactivity of lactic acid depends upon the experimental conditions.It acts as a two-or three-equivalent reducing agent in the absence or presence of Mn(II).It was examined that Cr(III)products resulting from the direct reduction of Cr(VI)by three-equivalent reducing agents.The oxidation of lactic acid follows the complex order kinetics with respect to [lactic acid].The activation parameters Ea,ΔH#,and ΔS# were calculated and discussed.
