离子交换树脂吸附乙酰丙酸的动力学研究

研究了大孔弱碱性树脂D310对乙酰丙酸的静态吸附动力学特征.采用批式离子交换法,考察了树脂粒径、溶液浓度、搅拌速率、温度对交换过程的影响,并用动边界模型对乙酰丙酸的离子交换过程进行了描述..结果表明,离子交换过程的控制步骤为颗粒扩散控制,搅拌速率和反应温度对交换速率无显著影响,吸附速率随乙酰丙酸初始浓度的增加而升高.交换过程的反应速率常数k0为0.8315,反应级数n为0.5313,表观活化能Ea为9.504kJ/mol,并得到了动力学总方程式.     

离子交换法分离乳酸的研究

本文对离子交换法分离乳酸的离子交换树脂、交换相平衡和交换动力学进行了研究,并在离子交换柱上测定了南开大学化工厂生产的201×4树脂的交换曲线。实验结果说明,用离子交换法分离发酵液中乳酸是可行的。     

离子交换纤维的交换动力学研究

本文研究了VS-1型强酸性阳离子交换纤维的交换动力学.在有限浴条件下,用放射性示踪法,研究了温度,搅拌速度,溶液浓度及pH 值对该离子交换纤维的异相同位素交换反应的影响.并推导出离子交换纤维的交换动力学方程,计算出不同条件下的粒内扩散系数D及液膜中的传输系数D/δ.从机理上明确了交换纤维的交换反应速率远比球形树脂快的原因     

钙阻抗剂的离子交换反应动力学和热力学研究

离子交换树脂是一类功能高分子材料 ,为研究某些药物离子的交换反应特性用以指导新型离子交换树脂控释给药系统的设计 ,选择钙通道阻滞剂盐酸维拉帕米和盐酸地尔硫 卓 作为模型药物 ,以 0 0 1× 7树脂作为药物载体 ,研究了该树脂与上述药物的交换反应动力学和热力学。结果表明 ,盐酸维拉帕米、盐酸地尔硫 卓 与 0 0 1× 7树脂的交换率随温度的升高而增加 ,温度升高可显著提高树脂的载药量。 2 5℃交换反应达平衡时 ,两药物的平衡常数Ke 分别为 0 .0 5 2 7和 0 .5 63 5 ,说明盐酸地尔硫 卓 易与树脂发生交换反应 ,即此树脂对药物的亲和力大 ;两药物与树脂交换反应的自由能变化ΔG°(kJ·mol- 1 )分别为 7.2 91和 1.42 1,说明交换反应不能自发进行 ,交换反应热ΔHm°(kJ·mol- 1 )分别为 85 .3 6和 5 8.2 8,说明交换反应为吸热反应 ,温度升高有利于向交换反应方向进行 ;交换反应熵变ΔS° >0 ,说明交换反应是熵变增加的反应。通过上述研究 ,可为新型离子交换树脂释药系统的设计提供坚实的理论基础。     

DuoliteA-30树脂对5’-三磷酸尿苷的静态吸附热力学及动力学特征

研究了DuoloyeA-30树脂对水溶液中5'-三磷酸尿苷(UTP)的静态吸附热力学和动力学特征,测定了不同温度下吸附等温线热力学性能的变化,利用热力学函数关系计算了吸附焓、自由能和吸附熵,确定在实验范围内,DuoliteA-30树脂对UTP的吸附符合Langmuir吸附等温式,吸附过程为自发的吸热过程.考察了温度、浓度、粒径、溶液pH值和搅拌速度对交换过程的影响,运用动边界模型(MBM)描述交换过程的动力学,确定在实验范围内离子交换行为的速度控制步骤为颗粒扩散,并推算出了交换过程的表观活化能,反应级数以及速率常数,得到了UTP在DuoliteA-30树脂上的动力学总方程.     

粒度不均一交换剂的离子交换反应动力学(Ⅰ)——粒内扩散或液膜扩散控制反应速度的同位素交换反应

本文研究了包含不同半径离子交换剂体系的同位素交换反应动力学。对于粒内扩散和液膜扩散控制反应速度的不均一体系,导出了表述离子交换剂和有限浴溶液中离子之间异相同位素交换反应交换度。     

硼特效树脂吸附硼的动力学研究

采用动边界模型对硼特效树脂XSC-800吸附模拟废水中硼酸根离子的动力学进行了描述.采用有限浴方法考察了体系温度、搅拌速度、树脂粒径及溶液中硼酸根离子浓度对交换过程的影响,并得到了交换动力学总方程.确定了硼酸根离子的交换过程属颗粒扩散控制,交换过程的表现活化能为20.38kJ/mol,表观反应级数为1.661.     

国内离子交换法处理氰化镉废水的现状及改进意见

本文对国内现行离子交换法处理氰化镀镉废水的工艺进行了探讨，提出了用络合理论将阴树脂由Ｃｌ－１型转变成ＣｄＣｌ４２－型后交换，便可提高对水中游离氰（ＣＮ－）的吸附能力，并能使氰、镉都得到回收利用。     

离子交换剂应用文摘

用重量分析法试验测定乙胺在二种H型离子交换剂(同质凝胶型和双孔的MR型)上的吸附平衡等温线和动力学数据。根据酸—碱中和反应,气体胺被吸附在干树脂上,并且饱和交换容量与树脂的交换容量相一致。对于凝胶型树脂来说,平衡是不利的,在上面的试验范围内等温线几乎是线性的。动力学数据也反映出二种吸附剂之间在结构上的差异。在MR型树脂     

盐酸地尔硫卓药物树脂复合物的制备及其体外释药动力学研究

本文以强酸性阳离子交换树脂为载体，制备了盐酸地尔硫卓(DH)药物树脂复合物。研究了DH与001×7树脂的交换反应动力学以及药物树脂复合物在去离子水、0.5mol/L、1.0mol/L、2.0mol/L NaCl和在0.5mol/L HCl以及0.5mol/L KCl溶液中的释药动力学。结果表明，在制备药物树脂的过程中，随温度的升高，药物与树脂的交换速率增加，及有利于反应的进行；药物树脂复合物在去离子水中不释放药物，但其释放随释放介质浓度的增加而增加，并且属于粒扩散的离子交换控制，粒扩散系数Dr随离子强度的增加而增加，DH的释药动力学过程符合对数方程（Visuanathan方程），001×7树脂可有效地控制DH在体外的释放。     

磷酸可待因在安伯来特IRP-69上的离子交换平衡特性研究

采用批式离子交换法研究了磷酸可待因在安伯来特IRP-69上的离子交换平衡特性、动力学及热力学特征.结果表明,在3个温度(298K、308K和318K)及研究的浓度范围内,离子交换吸附等温方程和Freundlich方程都能够对磷酸可待因在安伯来特IRP-69上的离子交换平衡等温线进行很好的拟合,其离子交换动力学特征基本符合二级动力学方程.磷酸可待因在安伯来特IRP-69上的离子交换行为的热力学参数(ΔH、ΔG、ΔS)都小于0.在3个温度(298K、308K和318K)下,同一初始浓度(350mmol/L)的磷酸可待因在安伯来特IRP-69上的平衡交换吸附量分别为1.1295mmol/g、1.1203 mmol/g和1.1129 mmol/g.     

The kinetics and mechanism of bromide ion isotope exchange reaction in strongly basic anion-exchange resin duolite A-162 determined by the radioactive tracer technique

In the present investigation, ⁸²Br radioactive isotope was used as a tracer to study the kinetics and mechanism of exchange reaction between an ion exchange resin and an external bromide ion solution. In an attempt to study the reversible bromide ion isotopic exchange reaction kinetics, it was expected that whether the initial step was the exchange of radioactive bromide ions from the solution into the ion exchange resin (forward reaction) or from the ion exchange resin into the solution (reverse reaction), two ion isotopic exchange reactions should occur simultaneously, which was further confirmed by the experimental specific reaction rates of 0.130 and 0.131 min⁻¹, respectively. The results can be used to standardize process parameters so as to optimize the utilization of ion exchange resins in various industrial applications. The text was submitted by the authors in English.     

Combined Water and the Ion Exchange Characteristics of Manganese Dioxide Produced by Ozonation

The change in ion exchange properties of manganese dioxide produced by ozonation (OMD) was studied with respect to its preheated temperature. This was performed by heating samples to different temperatures and later, saturating a part of them in aqueous cadmium sulfate solutions. Analyses were practiced on both the cadmium ion exchanged and un-ion exchanged samples. Results showed that the ion exchange reaction followed a stoichiometric relation between the hydrogen and cadmium ions, promoted by the combined water. The molar ratio of combined water to exchanged cadmium was found to be five. X rays and photographs taken in the scanning electron microscope showed that the structure and morphology of the OMD were not modified by the insertion of the cadmium during ion exchange. From the X rays, the structure of the OMD was determined to be of the gamma type. When the samples were heated to 400 and 500 degrees C, the crystal structure changed to beta and finally to Mn2O3, respectively. However, the changes in structure alone apparently did not affect the ion exchange. The surface area, measured by the BET technique, diminished linearly with the preheat temperature. The ion exchanged cadmium and the surface area showed a nonlinear relationship. However, the surface area and the quantity of combined water in the OMD were both linearly affected by preheating and are directly related to the ion exchange capacity. Copyright 1999 Academic Press.     

The application of the radioactive tracer technique to study the kinetics of bromide isotope exchange reaction with the participation of strongly basic anion exchange resin indion FF-IP

In the present investigation, the ⁸²Br radioactive isotope was used as a tracer to study the kinetics and mechanism of the exchange reaction between an ion exchange resin and an external solution of bromide ions. In an attempt to study the reversible bromide isotope exchange reaction kinetics, it was expected that whether the initial step was the exchange of radioactive bromide ions from the solution to the ion exchange resin (forward reaction) or from the ion exchange resin to the solution (reverse reaction), the two ion-isotope exchange reactions should occur simultaneously, which was further confirmed by the experimental values of specific reaction rates, 0.142 and 0.141 min⁻¹, respectively. The results will be useful to standardize the process parameters so as to achieve optimum use of ion exchange resins in various industrial applications. The text was submitted by the authors in English.     

三聚磷酸二氢铝吸附Cd~(2+)的动力学研究

采用动态吸附法研究三聚磷酸二氢铝吸附镉离子的动力学行为并进行吸附活化状态热力学参数分析。结果表明,当三聚磷酸二氢铝粒径小于150μm、搅拌器转速大于200r/min、Cd2+的初始浓度为500mg/L时,三聚磷酸二氢铝对镉离子的化学吸附符合二级反应动力学方程,吸附速率常数k与温度T之间的关系符合Arrhenius方程式,吸附的活化能为Ea=27.93kJ/mol,吸附的频率因子A=65.33L/mg·min,ln(k/T)与1/T之间的关系符合Eyring公式,其活化焓ΔH=25.44kJ/mol,活化熵ΔS=-218.54J/mol·K。     

Film-Pore Diffusion Control for the Batch Sorption of Cadmium Ions from Effluent onto Bone Char

The sorption equilibrium and kinetics of cadmium ions from aqueous solution onto bone char have been studied. Equilibrium isotherms for the sorption system were correlated by Langmuir and bi-Langmuir equations. The application of the bi-Langmuir equation was developed because the mechanistic analysis in this research indicated that cadmium removal occurs ion exchange and physical adsorption onto different surface sites. The bi-Langmuir equation provides a better fit to the experimental data. In addition, the removal rates of cadmium ions based on the Langmuir models have been investigated. The effective diffusivity was calculated using the effects of initial metal ion concentration and bone char mass. Two mass-transport models based on film-pore diffusion control have been applied to analyze the concentration decay curves. The film and pore diffusion coefficients using an analytical equation are equal to 1.26x10(-3) cm/s and 5.06x10(-7) cm(2)/s, respectively. The pore diffusion coefficient obtained from the numerical method is 4.89x10(-7) cm(2)/s. A sensitivity analysis showed that the film-pore diffusion model and constant effective diffusivity could be used to describe the mass-transport mechanism of the sorption system with a high degree of correlation. Copyright 2001 Academic Press.     

纳米钛酸钙粉体的制备及其对水中铅和镉的吸附行为

采用柠檬酸络合溶胶-凝胶法制备了纳米钛酸钙粉体. 以X射线衍射(XRD)、透射电子显微镜(TEM)和傅立叶变换红外光谱(FTIR)对其进行了表征. 考察了该纳米粉体对水中重金属铅和镉的吸附性能, 并以镉离子为例, 系统地研究了吸附热力学和动力学. 结果表明, 该法合成的钛酸钙为钙钛矿结构的纳米粉体, 粒径大小受灼烧温度的影响, 灼烧温度越高, 粉体平均粒径越大, 600 ℃灼烧2 h条件下, 粉体的平均粒径最小, 约为20 nm. 当介质的pH值为4～8时, 钛酸钙对水中的铅和镉具有很强的吸附能力. 其对镉离子的吸附行为符合Langmuir 吸附等温模型和HO准二级动力学方程式, 吸附过程焓变(ΔH)为39.312 kJ•mol－1, 各温度下的自由能变(ΔG)均小于零, 熵变(ΔS)均为正值, 吸附过程的活化能(Ea)为20.359 kJ•mol－1. 该吸附过程是自发的吸热物理过程. 被吸附的铅和镉均可用1 mol•L－1的硝酸完全洗脱回收. 对铅和镉的富集因子均超过200. 将其应用于水中痕量铅和镉的吸附富集和测定, 回收率分别为96.3%～107.2%和93.5%～104.0%, 与石墨炉原子吸收光谱法测定结果一致.