采用索氏提取法提取水浸预处理后的五味子中的木脂素,考察了虹吸次数、液固比、颗粒粒径及乙醇浓度对萃取率的影响,采用响应面法进行优化.结果表明,五味子醇甲的最佳提取条件为:乙醇浓度98.05%(?),液固比67.20m L/g,颗粒平均粒度0.33 mm,该条件下理论萃取率为80.90%,实际萃取率为77.17%;五味子甲素的最佳提取条件为:乙醇浓度96.38%(?),液固比72.52 m L/g,颗粒平均粒度0.21 mm,该条件下五味子甲素理论萃取率为77.11%,实际萃取率为74.31%;五味子乙素的提取最佳条件为:乙醇浓度96.38%(?),液固比72.52 m L/g,颗粒平均粒度0.21mm,该条件下理论萃取率为77.13%,实际萃取率为74.23%.各因素对木脂素提取率影响的显著性顺序为乙醇浓度>液固比>颗粒粒径.
采用有机溶剂对杜仲叶中绿原酸进行浸提,用高效液相色谱法对绿原酸进行定性定量分析,考察了液固比、乙醇浓度、温度和时间对绿原酸浸出率的影响,并对绿原酸浸出过程进行了动力学模拟.结果表明,绿原酸浸出的最优条件为乙醇浓度60%(?),液固比10 m L/g,在60℃下提取40 min,该条件下绿原酸的浸出率达90.21%.乙醇浸提杜仲叶中绿原酸符合内扩散动力学模型,表观活化能Ea=11.46 k J/mol.
The adsorption behavior of ion exchange resin D301 in the extraction of hexavalent molybdenum from high acidic leach solution was investigated. SEM, EDS and Raman spectra analyses were applied to studying the adsorption capacity, reaction kinetics and possible adsorption mechanism in detail. Results showed that the adsorption capacity of D301 resin for molybdenum from high acidic leach solution was up to 463.63 mg/g. Results of the kinetic analysis indicated that the adsorption process was controlled by the particle diffusion with the activation energy 25.47 k J/mol（0.9-1.2 mm） and 20.38 k J/mol（0.6-0.9 mm）. Furthermore, the molybdenum loaded on the resin could be eluted by using 2 mol/L ammonia hydroxide solution. Besides, dynamic continuous column experiments verified direct extraction of molybdenum from acidic leach solutions by ion exchange resin D301 and the upstream flow improved dynamic continuous absorption.
Hierarchical mesoporous MoO2/Mo2C/C microspheres,which are composed of primary nanoparticles with a size of about 30 nm,have been designed and synthesized through polymer regulation and subsequent carbonization processes.The as-synthesized microspheres were characterized by XRD,Raman,SEM,TEM,XPS measurements and so on.It was found that polyethylene glycol acted as a structure-directing agent,mild reducing agent and carbon source in the formation of these hierarchical mesoporous Mo O2/Mo2C/C microspheres.Moreover,the electrochemical property of the microspheres was also investigated in this work.Evaluated as an anode material for lithium ion batteries,the hierarchical mesoporous Mo O2/Mo2C/C electrode delivered the discharge specific capacities of 665 and 588 m Ah/g after 100 cycles at current densities of 100 and 200 m A/g,respectively.The satisfactory cycling performance and controllable process facilitate the practical applications of the hierarchical mesoporous Mo O2/Mo2C/C as a potential anode material in high-energy density lithium-ion batteries.
The electro-reduction of chromium oxide（Cr2O3） was investigated in an equimolar mixture of CaCl2-NaCl molten salt at 800℃ for developing a more efficient process for chromium preparation. Cyclic voltammetry and potentiostatic electrolysis were used to study the electro-reduction of the Cr2O3-loaded metallic cavity electrode. In addition, a number of parameters affecting the rate and extent of Cr2O3 electrolysis were considered to better understand the electrolysis process. The results demonstrate that CaCl2-NaCl molten salt is applicable for preparing Cr directly from Cr2O3 and the electrolysis parameters exert great influence on the cathode product. Under optimal experimental conditions, nodular Cr with an oxygen content of 0.5%（mass fraction） was obtained without any chromium carbides detected by XRD. Furthermore, the relatively high solubility of CaO and quite rapid crystal growth result in the formation of large platelet CaCr2O4, and the addition of NaCl to CaCl2 results in several variations on the electrolysis process and the product morphology from pure CaCl2 molten salt.
