大孔螯合树脂对Pb2+的吸附行为及机理

通过静态和动态吸附实验,研究了Pb2+在D418树脂上的吸附行为,从热力学和动力学方面对吸附过程进行了分析,并通过红外光谱探讨了吸附机理. 结果表明,在所研究的条件范围内,Pb2+在D418树脂上的吸附是吸热过程,同时符合Freundlich和Langmuir等温吸附方程;液膜扩散为Pb2+在D418树脂上吸附速率的主要控制步骤,随着溶液初始浓度的增大,吸附速率逐渐减小;313 K温度下树脂的静态饱和吸附容量为375 mg/g,在298 K下用3 mol/L的硝酸作为解吸剂,解吸率可达97%;最佳的解吸剂用量为5倍床层体积. 该树脂吸附操作简单,易再生,不产生二次污染,有望用于含铅废水的治理及铅的富集.     

树脂吸附环已酮中己醛的研究

本文考察了3种树脂对环己酮中所含己醛的吸附能力,并用动态实验研究了树脂床层高径比、流速、己醛初始浓度对树脂吸附能力的影响.结果表明1*树脂效果较好,适宜流速为2～3BV(BV为树脂床层体积),床层高径比对吸附效果影响不大,己醛初始浓度越低,吸附效果越好.     

大孔树脂富集多舌飞蓬总咖啡酸酯的工艺

考察了13种不同极性的大孔吸附树脂对多舌飞蓬中总咖啡酸酯的富集纯化能力,发现极性树脂NKA-2的静态吸附率为92.51%、解吸率为98.51%,明显优于其他树脂。进一步以NKA-2极性树脂对多舌飞蓬总咖啡酸酯进行静态吸附与动态吸附实验,结果表明,最佳上样质量浓度为300 g/L,最佳上样流速为2 BV/h(BV/h即每小时内,通过床层液体体积的倍数),树脂吸附容量为6 m L/g,即每克NKA-2树脂可以处理1.8 g生药。解吸实验结果表明,用体积分数为60%的乙醇水溶液洗脱,洗脱剂用量为30 m L/g树脂。用上述条件对多舌飞蓬总咖啡酸酯富集纯化,使总咖啡酸酯的纯度由18.09%提高到58.06%,回收率高达94.78%。说明NKA-2型大孔吸附树脂综合性能良好,可用于多舌飞蓬中总咖啡酸酯成分的富集和纯化。     

钴锌离子交换分离条件优化研究

采用正交试验法对不同含量混合液中Co2 、Zn2 在离子交换柱上的吸附、分离及交换分离条件进行了研究.以Zn2 的回收率(η)作为评价指标,结果表明,CoCl 的洗脱速率和树脂床层高度对η的影响最大,Co2 、Zn2 配比的影响次之,混合液的进样体积量影响最小;并得到了最佳分离条件为:CoCl 的洗脱速率为1.0 mL/min,树脂床层高度12 cm,混合液中Co2 、Zn2 配比10/6,混合液的进样量1.0 mL.最佳条件下Zn2 的回收率达97.35%.     

花生壳中黄酮类化合物的提取纯化工艺研究

花生壳中以木犀草素为主的黄酮类化合物,具有抗氧化、抗肿瘤、抗炎症等活性,可广泛用于医药、食品、化妆品和保健品等领域。采用微波-碱水辅助提取花生壳中的总黄酮,考察影响花生壳总黄酮提取率的因素,当微波功率420 W,料液比(mL/g,下同)为1∶25,微波时间120s,氢氧化钠浓度0.06mol/L时,花生壳总黄酮提取率为5.3mg/g,纯度为14.2%。采用D-101大孔吸附树脂纯化花生壳粗提取液中的总黄酮,考察D-101树脂对总黄酮的的吸附洗脱作用。由静态吸附动力学曲线得出,D-101树脂在5h内达到吸附平衡,吸附饱和量为1.4mg/g;动态吸附解吸时,解吸液乙醇体积分数为80%,过柱速度为0.5mL/min,泄露曲线表明,当流经4.5倍床层体积的花生壳粗提取液时,流出液浓度趋于初始浓度,树脂达到吸附平衡状态;动态洗脱曲线表明,洗脱剂用量为4倍床层体积时,可实现总黄酮完全洗脱。由D-101大孔吸附树脂纯化花生壳总黄酮的纯度由14.2%提高到58.8%。     

过滤-吸附法回收废盐酸的技术研究

采用过滤-吸附法对含高浓度有机物废盐酸进行回收处理的实验研究,实验分别考察了纤维球、活性炭、树脂的物理性质,探究了废液过滤吸附流速、吸附剂质量及废液浓度对过滤吸附效果的影响。结果表明,实验最佳工艺参数为:纤维球柱与活性炭柱、树脂柱串联;纤维球柱填充纤维球质量50 g,活性炭柱填充质量130 g,流速0.25 BV/h;树脂柱填充床层体积50 m L,流速2 BV/h,实验得到油含量低于10 mg/L的洁净盐酸50 BV,回收率较高,实现了废盐酸的再生循环利用。     

大孔吸附树脂对喜树叶中喜树碱的纯化工艺研究

研究通过静态吸附/解吸实验对大孔吸附树脂进行筛选,优选AB-8大孔吸附树脂作为层析柱填料,并对其进行喜树碱纯化工艺研究;研究表明AB-8树脂对喜树碱的静态吸附率为95.31%;体积分数95%的乙醇静态解吸率为92.4%;最佳吸附条件为:上样液质量浓度为0.175mg/mL,上样液不调pH值,吸附流速为2BV/h,平衡吸附5h;最佳洗脱条件:体积分数95%乙醇,洗脱流速1BV/h,洗脱体积为8BV。在该工艺条件下,洗脱物中喜树碱质量分数为7.43%,洗脱率为83.1%。     

X-5大孔树脂对黄芪异黄酮的吸附特性

通过对比5种大孔树脂对黄芪异黄酮的吸附和解吸特性,发现X-5大孔树脂最适用于吸附黄芪异黄酮,并进一步采用静态吸附法研究了X-5树脂对黄芪异黄酮的吸附动力学和热力学特性。动力学研究表明,准二级动力学相对于其它模型而言能够更好地描述黄芪异黄酮的吸附过程,颗粒内扩散是整个吸附过程的主要速率控制步骤;黄芪异黄酮的吸附符合Langmuir等温吸附模型。热力学研究表明,ΔG0<0即吸附是自发进行的,ΔH0和ΔS0分别为8.021 kJ/mol和62.51 J/(mol?K)说明X-5大孔树脂对黄芪异黄酮的吸附是以熵为主要驱动力的吸热 过程。     

大孔吸附树脂法纯化山楂黄酮的工艺研究

对5种大孔吸附树脂纯化山楂黄酮的效果进行了比较.结果表明,X-5吸附树脂的纯化效果最好.通过对纯化影响因素的研究,确定了以X-5树脂纯化山楂黄酮最优的工艺条件为:山楂黄酮水溶液的浓度为2.0 mg·mL-1,pH为3,上柱流速为3 BV·h-1,用3 BV体积分数为70%的乙醇解吸.采用X-5吸附树脂纯化后,最终产品纯度为93.25%,满足了作为药品原料药的纯度要求.     

过滤-吸附法回收废盐酸的技术研究

采用过滤-吸附法对含高浓度有机物废盐酸进行回收处理的实验研究,实验分别考察了纤维球、活性炭、树脂的物理性质,探究了废液过滤吸附流速、吸附剂质量及废液浓度对过滤吸附效果的影响。结果表明,实验最佳工艺参数为:纤维球柱与活性炭柱、树脂柱串联;纤维球柱填充纤维球质量50 g,活性炭柱填充质量130 g,流速0.25 BV/h;树脂柱填充床层体积50 m L,流速2 BV/h,实验得到油含量低于10 mg/L的洁净盐酸50 BV,回收率较高,实现了废盐酸的再生循环利用。     

Isobutanol from synthesis gas

A highly active and selective Zr-Zn-Mn-Li-Pd catalyst for the one-step synthesis of 2-methyl-1-propanol (isobutanol) from synthesis gas is described. This catalyst produces 60 wt% isobutanol at a rate of 740 g isobutanol per liter catalyst and hour. The catalyst was optimized by a statistical method indicating that during catalyst preparation pH and temperature control are essential.Abbreviations GHSV gas hourly, space velocity defined as volume incoming syngas/volume catalyst and hour at standard conditions - MTBE methyl tert. butyl ether     

Segregation in a stirred fluidized bed

A bed of particulate solids supported by an upward current of gas can be stirred at moderate power input per unit volume using thin horizontal rods mounted on a vertical shaft. The bed is fluidized, but bubbles are suppressed below a critical value of the fluidizing velocity. Stirring increases bed bulk density and reduces the minimum fluidizing velocity. Segregation in a stirred fluidized bed is enhanced with both flotsam and jetsam tracer particles, but the rate of segregation is reduced with flotsam tracers. The stirred fluidized bed may be useful as a device for dry separation of solids.     

苦豆子生物碱单体的分离纯化工艺研究

在对苦豆子的酸水浸提液进行了超滤和脱色预分离的基础上,采用不同的有机溶剂萃取和硅胶柱层析对其中主要的生物碱进行分离纯化及条件优化.结果表明合适的生物碱萃取富集条件是用氯仿为溶剂,Ph=10.5.该氯仿萃取液用硅胶柱层析分离,洗脱剂为氯仿-甲醇-氨水(5:0.4:0.01,V/V/V),洗脱速度1柱床体积·h-1,得到峰1～峰3.峰1和峰2中的化合物经丙酮结晶和重结晶分别得到纯度99%以上的氧化槐果碱和氧化苦参碱;峰3对应的组分再经硅胶柱层析,洗脱剂为丙酮-甲醇(10:1,V/V),洗脱速度1柱床体积·h-1,得到峰4～峰6,峰4中的化合物经石油醚结晶和重结晶,可以得到纯度95.8%的槐定碱.采用了HPLC-MS,IR,熔点测定和薄层色谱等方法进行上述生物碱单体的定性定量及分子结构确定. 本研究为深度开发苦豆子生物碱资源和为制备医药工业所需的高纯度生物碱原料提供了依据.     

A comprehensive interpretation of solid layer inversion in liquid fluidised beds

Solid mixing and segregation in liquid fluidised beds containing binary mixtures of spherical particles of different density and size has been studied for a range of liquid velocities, bulk bed compositions and particle properties. It was shown that a bed of denser particles expands with liquid velocity independently of the presence of the lighter particles. When the bulk volume fraction of the lighter particles is high and the liquid velocity is relatively low, the bed forms two layers, i.e. the upper layer consisting almost entirely of the lighter and the lower mixed layer consisting of both components in which the volume of the lighter increases with liquid velocity. A completely mixed bed is obtained at a certain velocity and then a further increase of the velocity causes “layer inversion”. The liquid velocity at which complete mixing occurs depends on the bulk bed composition, and at that velocity the volume fraction of the lighter in the lower mixed layer is constant regardless of the bulk bed composition. It is shown that layer inversion occurs for a given particle mixture when the liquid velocity passes through a value at which the volume fraction of the lighter in the lower layer becomes equal to the bulk bed composition; or for a given velocity, when the bulk bed composition becomes equal to the fraction of the lighter component which exists in the lower layer. The dependency of the fraction on the liquid velocity and the particle properties is examined to some extent.     

Behavior of Pieces of Plastic Sheet in Solid‐Liquid Fluidized Bed with Stirring

A solid‐liquid fluidized bed of inert particles can be used to separate pure objects from a mixture. Pieces of plastic sheet were selected as the objects to be separated. To estimate the separation characteristics, the behavior of pieces of plastic sheet in the bed was examined experimentally. Slow stirring was used to improve the fluidization state of the bed. The object size and the volume ratio of objects to inert particles were varied. The use of stirring of the bed was effective in improving the fluidization state of the bed, and the objects, which sank in the bed without stirring, moved from the bottom to the upper portion of the bed at a certain liquid velocity. This liquid velocity increases with decreasing object size, and it also increases as the volume ratio of objects to inert particles in the bed increases. When the volume ratio of objects to inert particles is too high, the objects are distributed throughout the entire bed, regardless of the liquid velocity.     

An investigation of mass transfer in a countercurrent three-phase fluidized bed

The rate of absorption with chemical reaction has been measured in a bed of solid spheres fluidized by upward flowing gas and irrigated by downward flowing liquid for different reactant concentrations in the liquid phase and different values of the liquid superficial velocity.Values of the effective inerfacial area per unit volume of a static bed, a, and the gas-film mass-transfer coefficient, k_g, are reported as functions of the liquid superficial velocity.     

三维喷动床内异径干湿颗粒混合特性数值模拟

基于计算流体力学-离散单元法,建立了三维喷动床内气固两相流数学模型,采用Fortran语言编制了并行数值模拟程序。对三维喷动床内两种不同直径的干颗粒及湿颗粒的混合特性进行了数值模拟,并从颗粒角度分析了双组分颗粒的运动机制。利用Lacey混合指数对床内整体以及特定区域的混合程度进行了定量分析,并研究了液桥体积、颗粒密度比以及表观气速对异径颗粒混合的影响。结果表明：在单孔射流喷动床内,干湿两种颗粒流动方式相似,湿颗粒无明显的聚团现象;液桥力对小直径的颗粒影响较大,使不同直径湿颗粒速度差减小;环隙区内颗粒的混合是影响整床颗粒混合的关键因素;液桥体积对颗粒混合的影响较大,对颗粒密度比以及表观气速的影响有限。     

基于LBM-DEM的鼓泡床内气泡-颗粒动力学数值模拟

将修正后的格子Boltzmann方法（LBM）与离散单元法（DEM）相结合,建立LBM-DEM四向耦合模型对单口射流鼓泡床中气泡运动进行模拟。其中,流体相采用格子Boltzmann方法中经典的D2Q9模型,颗粒相求解采用离散单元软球模型,颗粒曳力求解采用Gidaspow模型,流固耦合基于牛顿第三定律。应用Fortran语言编程对上述模型进行求解,模拟得到了鼓泡床内气泡演化过程,并与相关实验进行对比,有效验证了当前模型的准确性。同时,分析了床层内颗粒速度、颗粒体积分数以及能量分布。结果表明：颗粒时均速度分布不仅能体现颗粒运动强弱,也可以反映气泡运动过程;床内空隙率与颗粒体积分数分布在预测床层膨胀高度上具有高度的一致性;初始堆积效应使得床内颗粒势能始终大于颗粒动能;随颗粒密度增加,势能增大,动能逐渐减小。     

基于声发射信号递归分析的气固流化床流型转变

利用声发射技术采集不同流化气速下流化床内颗粒与壁面碰撞的声信号,结合声能量及递归分析法研究不同流型下颗粒运动特征,得到鼓泡流态化到湍动流态化的临界转变速度及流型转变规律。特别是针对声能量分析无法准确区分不同床层高度处流型转变的不足,利用递归分析可有效预测系统周期性的特点,将声信号进行递归分析,研究了流化床不同位置的流型转变性质。结果表明,鼓泡流态化下颗粒运动的周期性较湍动流态化强,并能够清晰地检测到由鼓泡流态化向湍动流态化的流型转变速度,而且床层较低处的流型转变速度比床层较高处大。由此获得了一种便捷灵敏、安全环保的非侵入式流化床流型转变速度的测量技术,可用于对整个流化床内不同位置流型转变过程的实时在线监控。     

Improvement of the performance of porous electrodes using ionic conducting particles: Application to silver recovery

Experimental measurements are reported for a complex conducting porous electrode system consisting of electronic and ionic conducting particles. A very large value of the ionic conductivity within the electrode is its main characteristic. The complex conducting electrodes and traditional graphitic granular electrodes were used separately to recover silver from a silver plating rinse water. The former displayed excellent performance. A packed-bed reactor composed of the complex conducting electrodes has been successfully tested on a plating line.Nomenclature a specific interfacial area of the electrode bed - c concentration of reactants - c _o initial concentration of reactants - F Faraday constant - I cell current - i ₀ exchange current density - L thickness of electrode bed - p electric power - Q volume flow rate - R universal gas constant - r percentage recovery of silver - s space velocity (i.e. the number of dm³ solution per dm³ volume of electrode per hour) - S normalized space velocity (i.e. the number of dm³ solution whose concentration could be reduced tenfold per dm³ volume of electrode per hour) - T absolute temperature - U cell voltage - _a transfer coefficient for anode - _c transfer coefficient for cathode - porosity or void fraction of bed - average current efficiency - k effective conductivity of solution - intrinsic conductivity of solution - square root of dimensionless exchange current - effective conductivity of conducting solid matrix