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.
研究离子交换树脂D301在强酸性浸出液中对六价钼的吸附行为。利用扫描电镜(SEM)、电子能谱(EDS)和拉曼光谱(Raman spectra)对树脂的吸附能力、吸附动力学和吸附机理进行详细考察。结果表明,D301离子交换树脂在强酸性浸出液中的对钼吸附量达到463.63 mg/g,吸附控制步骤为颗粒内扩散过程,当树脂粒度从0.9~1.2 mm减小到0.6~0.9 mm时,活化能则从25.47 k J/mol降低到20.38 k J/mol。解析实验表明,2 mol/L的氨水可以作为D301树脂的解吸液。动态上柱实验验证离子交换树脂D301在强酸性浸出液对钼直接提取的可行性。此外,逆流吸附可以改善动态连续吸附效果。
Hierarchical mesoporous MoO_2/Mo_2C/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 O_2/Mo_2C/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 O_2/Mo_2C/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 O_2/Mo_2C/C as a potential anode material in high-energy density lithium-ion batteries.
