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     

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.     

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.     

大孔树脂对红霉素的吸附动力学研究

利用大孔吸附树脂Amberlite XAD16及HZ816对红霉素的吸附动力学实验,研究了温度、初始浓度、溶液pH值及搅拌速度等因素对吸附过程的影响.结果表明,Amberlite XAD16及HZ816对红霉素的吸附速率符合一级吸附动力学方程及颗粒内扩散方程,过程受液膜扩散阻力及颗粒内扩散阻力共同影响.同时,表观吸附速率常数与颗粒内扩散速率常数均随着温度的升高而增大,随着初始浓度的增大而增大,随着溶液pH值增大而增大,随着搅拌速度加快而增大.     

离子交换树脂吸附镉的动力学研究

实验采用离子交换法吸附氯盐体系中的镉,用动态法对2017型强碱性阴离子交换树脂的工作条件进行了优化,在最佳反应体系下,用批式离子交换法研究了温度、溶液浓度和树脂粒径对交换过程的影响,并用动边界模型描述交换过程的动力学,确定了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、速率常数和动力学总方程式。     

离子交换法纯化重组类人胶原蛋白Ⅱ的吸附动力学研究

为了确定重组类人胶原蛋白Ⅱ(Recombinant human-like collagen,RHLC Ⅱ)在CM52树脂上的动力学行为,考察温度、初始浓度等因素的影响,分别采用简单线性推动力模型(液膜扩散控制时)和均相扩散模型(颗粒扩散控制时)研究RHLC Ⅱ在不同工艺条件下的反应速率,确定离子交换过程的速率控制步骤,并计算模型参数.结果表明,(1)速率控制机理受转速和料液初始浓度的影响,在转速和料液初始浓度较低时,为液膜扩散控制(Film Diffusion Control,FDC);反之,则为颗粒扩散控制(Particle Diffusion Control,PDC);(2)以简单线性推动力模型拟合液膜扩散控制时的动力学数据,其线性关系良好,模型准确度较高;对于颗粒扩散控制的吸附,则以均相扩散模型拟合,求出有效扩散系数,模型较好地描述了CM52对RHLC Ⅱ的PDC吸附.(3)对于FDC,温度越高,溶液浓度越大,搅拌转速越高,外扩散速度常数越大,吸附越快;对于PDC,温度升高,有效扩散系数增大,吸附加快,料液浓度对有效扩散系数的影响不显著.     

A222型阴离子交换树脂脱除HPP水溶液中SO_4~(2-)的研究

论文研究了A222树脂在N,N'-二(2-羟丙基)哌嗪(HPP)脱硫胺液中对SO42-的离子交换性能,优化条件为振荡温度50℃、交换时间2h,HPP浓度0.5mol/L、SO42-浓度0.3mol/L、p H值5.1、固液比80g/L,此条件下,树脂的交换量达163.57mg/g。在HPP-SO42-中,A222树脂具有优良的稳定性和脱盐效果,在循环交换-解吸过程中,对SO42-的平均交换量为136.25mg/g、平均交换率51.37%、平均脱附率96.48%、室温下的动态交换量可达196.90mg/g。FT-IR和TG研究结果表明,HPP能通过物理吸附作用附着在A222树脂上,而树脂对SO42-的离子交换过程中有化学键生成。树脂对SO42-的吸附过程更好地遵循Freundlich等温吸附规律。     

新型硅胶-聚合胺树脂从氯化钴电解液中深度净化除铜

SP-C是一种新型硅胶-聚合胺复合材料树脂,对铜具有较好的选择吸附性能.本文研究了该树脂在模拟氯化钴电解液中深度净化除铜工艺.在Co2 ～80g/L,Cu2 0.5g/L～2.0g/L、pH2～4、温度20℃～60℃的氯化钴电解液中,考察了该树脂对铜的吸附性能.结果表明,随料液pH增大以及温度升高,铜的交换容量增大:料液Cu2 浓度对交换容量影响较小;最佳吸附条件为:料液pH 4、接触时间30min,温度60℃.对比研究了盐酸、硫酸两种解析液,硫酸显示出更好的解析效果,最佳解析条件为H2SO42mol/L、解析接触时间40min.最佳工艺条件下,每毫升湿树脂对铜的工作交换容量及饱和交换容量分别为0.439mol和0.508mol,铜的解析液峰值浓度为28g/L.     

新型硅胶-聚合胺树脂从氯化钴电解液中深度净化除铜

SP-C是一种新型硅胶-聚合胺复合材料树脂,对铜具有较好的选择吸附性能.本文研究了该树脂在模拟氯化钴电解液中深度净化除铜工艺.在Co2 ～80g/L、Cu2 0.5g/L～2.0g/L、pH 2～4、温度20℃～60℃的氯化钴电解液中,考察了该树脂对铜的吸附性能.结果表明,随料液pH增大以及温度升高,铜的交换容量增大;料液Cu2 浓度对交换容量影响较小;最佳吸附条件为:料液pH 4、接触时间30min,温度60℃.对比研究了盐酸、硫酸两种解析液,硫酸显示出更好的解析效果,最佳解析条件为H2SO4 2mol/L、解析接触时间40min.最佳工艺条件下,每亳升湿树脂对铜的工作交换容量及饱和交换容量分别0.439mol和0.508mol,铜的解析液峰值浓度为28g/L.     

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.     

Two-resistance mass transfer model for the adsorption of the pesticide deltamethrin using acid treated oil shale ash

Adsorption characteristics of the pesticides Deltamethrin were studied in aqueous solutions using acid treated Oil Shale Ash (ATOSA) in a series of batch adsorption experiments. The maximum loading capacity of the adsorbent and the rate of adsorption were found to increase with increasing the pesticide initial concentration, mixing speed and were found to decrease with temperature and particle size. Langmuir as well as Freundlich isotherm models fit the adsorption data with R ²>0.97 in all cases. The maximum adsorption capacity for Deltamethrin was 11.4 mg/g. The two-resistance mass transfer model based on the film resistance and homogeneous solid phase diffusion was used to fit the experimental data. A computer program has been developed to estimate the theoretical concentration-time dependent curves and to compare them with the experimental curves by means of the best-fit approach. The model predicts that the external mass transfer coefficient K was affected by varying the initial pesticide concentration, the agitation speed and temperature whereas the diffusion coefficient D was affected by the initial pesticide concentration, and temperature.     

Hydroxyapatite-coated carboxymethyl chitosan scaffolds for promoting osteoblast and stem cell differentiation

This study investigated the potential of MIEX resin as the adsorbent for the removal of phosphate from aqueous solutions. In our batch experiments, we studied the effect of some parameters on the removal of phosphate. It was observed that uptake of phosphate was mainly affected by initial phosphate concentration, adsorbent dosage, initial pH of solution, and coexistent anions. The adsorption equilibrium data at 288 K fitted well to Freundlich and Koble-Corrigan isotherm models. The kinetics studies displayed that the adsorption process followed the pseudo-second-order model. The diffusion studies showed that the intra-particle diffusion was not the only rate-controlling step and, the diffusion process of phosphate from solution to MIEX resin was controlled by film diffusion. The thermodynamics parameters were evaluated. The results showed that the adsorption process was spontaneous thermodynamically, endothermic, and entropy driven. These results have established a good potentiality for MIEX resin to be used as an adsorbent for the removal of phosphate from aqueous solutions. This work will deepen our understanding of the adsorptive characteristics of phosphate by MIEX resin and provide a better way to remove phosphate from wastewater.     

磁性海藻酸钙-壳聚糖凝胶珠吸附La~(3+)性能研究

利用直接法和间接法制备磁性海藻酸钙-壳聚糖凝胶珠,并考察了磁性凝胶珠对La3+的吸附性能。结果表明,水相pH值、振荡时间、温度及金属离子浓度均对吸附效果有显著影响。在选定吸附剂用量为0.05g前提下,吸附最佳pH值为4.0;平衡振荡时间5h,吸附过程符合假二级动力学反应模型;两种磁性凝胶珠的最大吸附量分别为208.3和232.6mg/g;此吸附过程是一个放热的过程;吸附机理为阳离子交换和表面螯合机理,海藻酸盐上的羧基官能团在吸附过程中起主要作用;再生实验表明,磁性凝胶珠可以重复利用。     

Kinetic and isotherm studies of Cu(II) adsorption onto H3PO4-activated rubber wood sawdust

Adsorption of Cu(II) from aqueous solution onto H(3)PO(4)-activated carbon using rubber wood sawdust (RSAC) was investigated in a batch system. Kinetic and isotherm studies were carried out by considering the effects of various parameters, such as initial concentration, contact time, pH, and temperature. The optimal pH value for Cu(II) adsorption onto RSAC was found to be 6.0. Thermodynamic parameters such as standard Gibbs free energy (DeltaG(0)), standard enthalpy (DeltaH(0)), and standard entropy (DeltaS(0)) were evaluated by applying the Van't Hoff equation. The thermodynamics of Cu(II) adsorption onto RSAC indicates its spontaneous and exothermic nature. Langmuir, Freundlich, and Temkin isotherms were used to analyze the equilibrium data at different temperatures. The Langmuir isotherm fits the experimental data significantly better than the other isotherms. Adsorption kinetics data were tested using pseudo-first-order, pseudo-second-order, and intraparticle diffusion models. Kinetic studies showed that the adsorption followed a pseudo-second-order reaction. The initial sorption rate, pseudo-first-order, pseudo-second-order, and intraparticle diffusion rate constants for different initial concentrations were evaluated and discussed. Adsorption mechanism studies revealed that the process was complex and followed both surface adsorption and particle diffusion. The rate-controlling parameter and effective diffusion coefficient were determined using the Reichenberg plot. It was found that the adsorption occurs through film diffusion at low concentrations and at higher concentration the particle diffusion becomes the rate-determining step.     

XDA-1树脂对茶多酚的吸附及吸附柱放大研究

研究了XDA-1树脂对茶多酚的吸附及吸附柱放大规律。建立了XDA-1树脂柱吸附茶多酚过程的传质模型，并根据该模型分别计算了不同操作条件下相应的物质总传质系数及传质区长度．结果表明，在实验操作的流速范围内，过程属于外扩散控制．按照操作线速度相等的原则进行固定床设备的放大，传质区长度的放大误差在10％左右，实验所得传质区长度的结果可作为吸附柱设计的基础．     

柠檬酸在D354树脂上的离子交换研究

研究了大孔型弱碱性阴离子交换树脂Ｄ３５４分离水中柠檬酸的相平衡和动力学。Ｌａｎｇｍｕｉｒ方程能够良好地关联等温线。建立了离子交换过程的孔扩散模型，并以正交配置法与Ｇｅａｒ法结合进行数据拟合。结果表明，液膜阻力对交换过程具有重大影响，简单线性推动力模型能够很好地描述液膜传质过程。     

胺修饰酚醛树脂对酸性橙Ⅱ的吸附性能研究

研究了自制胺修饰酚醛树脂(AMPF)对水溶性染料酸性橙II的吸附性能,探讨了pH值、温度、浓度等因素对酸性橙吸附性能的影响。结果表明,AMPF与市售大孔树脂D296和D301相似,对酸性橙均具有较强的吸附能力。温度升高有利于AMPF对酸性橙的吸附;酸性橙浓度升高,吸附量增大。AMPF对酸性橙的吸附符合Boyd液膜扩散控制。各种树脂对酸性橙的平衡吸附数据符合Langmuir方程和Freundlich等温式,其相关系数大于0.98,n均大于1,表明为优惠吸附。     

63Ni在泥煤-水体系中的吸附动力学

应用同位素示踪技术,简要地研究了63Ni在泥煤中的静态吸附行为。结果表明,5 min后泥煤对63Ni的吸附率可达69%,60min后达到吸附平衡;第1吸附阶段内镍吸附量随时间的延长而增加,不易解吸;从泥煤-水液固体系中泥煤的电离平衡和镍离子-氢离子之间离子交换平衡,以及物料平衡关系推导出泥煤平衡时63Ni的吸附量和氢离子的浓度、平衡时镍离子的浓度有关。溶液的pH值对镍的吸附和解吸有很大影响,随着溶液pH值增大,63Ni由水分室向泥煤分室转移的速率常数也逐渐增大,而由泥煤分室向水分室转移的速率常数逐渐减小,二者比值逐渐增大,pH=4.624 6时,2种可逆传递速率常数相等,为2.51。即适宜pH值范围内的pH值升高吸附量增大,低pH值不利于吸附。63Ni在泥煤-水体系中的动态变化可用封闭二分室进行描述,经拟合后的理论值与实验数据点具有较好的一致性。     

Parallel pore and surface diffusion of levulinic acid in basic polymeric adsorbents

The equilibrium and kinetics of levulinic acid (LA) adsorption on two basic polymeric adsorbents, 335 (highly porous gel) and D315 (macroreticular), were investigated. Experimental adsorption rates in batch stirred vessels under a variety of operating conditions were described successfully by the parallel pore and surface diffusion model taking into account external mass transfer and nonlinear Toth isotherm. The film-pore diffusion model was matched with the rate data and the resulting apparent pore diffusivities were strongly concentration-dependent and approached to a constant value for 335 adsorbent. Thus, the constant value was taken as the accurate pore diffusivity, while the pore diffusivity in D315 was estimated from the particle porosity. The surface diffusivities decreased with increasing initial bulk concentration for both adsorbents. The inverse concentration dependence was correlated reasonably well to the change of isosteric heat of adsorption as amount adsorbed.