多孔离子交换树脂内Eu3+离子的分步扩散

用同位素交换法研究了Eu³⁺离子在D72和D751树脂内的扩散过程.应用分步孔道扩散方程将粒内有效扩散系数D_e分解为孔道扩散系数D_p和固相扩散系数D_g,表明该方程可用于描述多孔树脂内的动力学过程.实验表明,D_e、D_p、D_g均随反应温度的升高而增大.计算了实验条件下的Eu³⁺的自扩散活化能;D72树脂的D_p和D_g对温度的响应比D751树脂大,其D_e、D_p、D_g值亦均大于D751树脂;Eu³⁺在溶液中的自扩散系数D_s＞D_p,说明离子在树脂孔道内的自扩散不能完全等同于其在溶液中的自扩散.     

EDTA溶液中稀土离子在大孔树脂内的扩散

本文研究了EDTA溶液中稀土在大孔树脂内的扩散,用同位素交换法测定了ce,Tb、Yb的有效粒内自扩散系数(D_e)。D_e值受外部溶液浓度的影响。应用Kataoka双分散大孔扩散方程将D_e值分解为孔道扩散系数D_p和固相扩散系数D_g,表明该方程可用于描述大孔树脂的动力学过程。D_e随树脂粒度增大而增加,D_p远大于D_e,D_g接近于D_e,固相扩散是控制离子在大孔树脂扩散速率的决定步骤。     

多孔离子交换树脂内Eu^3＋离子的分步扩散

用同位素交换法研究了Ｅｕ＾３＋离子在Ｄ７２和Ｄ７５１树脂内的扩散过程。应用分步孔道扩方程将粒内有效扩散系数Ｄｃ分解为孔道扩散系数Ｄｐ和固相扩散系数Ｄｇ，表明该方程可用于描述多忆树脂内的动力学过程。实验表明Ｄｃ、Ｄｐ、Ｄｇ均随反应温度的升高而增大。     

弱酸强碱两性树脂解吸动力学的研究

本文采用浅床解吸法对离子在弱酸强碱两性树脂相内的扩散进行了研究．结果表明：阳离子所带电荷越多．其粒内扩散系数就越小，阴离子体积越大．电荷多．则粒内扩散系数也越小。     

西索米星在大孔弱酸树脂上的吸附研究与传质系数的测定

对西索米星在大孔弱酸树脂上吸附平衡与动力学进行研究。建立了间歇吸附表面有效扩散模型,利用实验测定了吸附平衡曲线和吸附速率曲线,结合正交配置法、遗传算法直接拟合出固相粒内表面有效扩散系数Dc和液相传质系数kf,其拟合均方根误差不大于0.025。研究结果表明,西索米星在D113树脂上的吸附平衡符合Langmiur方程,吸附速率实验数据与吸附模型数值解拟合良好,表面有效扩散模型能够很好地描述西索米星在弱酸树脂D113上的吸附行为。在实验条件下,表面有效扩散系数Dc约为2.00×10-8~4.09×10-8cm2/s,液相传质系数kf约为9.00×10-5~2.95×10-4cm/s。     

西索米星在大孔弱酸树脂上的吸附研究与传质系数的测定

对西索米星在大孔弱酸树脂上吸附平衡与动力学进行研究。建立了间歇吸附表面有效扩散模型,利用实验测定了吸附平衡曲线和吸附速率曲线,结合正交配置法、遗传算法直接拟合出固相粒内表面有效扩散系数Dc和液相传质系数kf,其拟合均方根误差不大于0.025。研究结果表明,西索米星在D113树脂上的吸附平衡符合Langmiur方程,吸附速率实验数据与吸附模型数值解拟合良好,表面有效扩散模型能够很好地描述西索米星在弱酸树脂D113上的吸附行为。在实验条件下,表面有效扩散系数Dc约为2.00×10-8～4.09×10-8cm2/s,液相传质系数kf约为9.00×10-5～2.95×10-4cm/s。     

两性树脂解吸动力学的研究──温度对扩散系数的影响

本文采用浅床法对阳离子在弱酸强碱两性树脂相内的扩散速度进行了研究。发现温度升高 ,其粒内扩散系数增大 ,离子价态越高 ,扩散过程的活化能就越大 ,表明温度的改变对高价阳离子的扩散速度的影响更显著     

离子交换平衡和动力学的研究(Ⅲ) Y~(3+)-H~+交换平衡和动力学

用强酸性阳离子交换树脂研究了Y~(3+)-H~+交换反应的平衡和动力学,测定了反应的等温线,求得合理热力学平衡常数Ka=1.9×10~2。实验表明,正交换反应RH/Y~(3+)符合一般规律,即在低浓度时,系液膜扩散机理,高浓度时,系粒内扩散机理;而逆交换反应R_3Y/H~+在本实验的浓度和搅拌速度下,均为粒内扩散机理。正逆交换反应机理的差别是树脂对三价稀土元素Y~(3+)具有极高的亲和性所致。估算了液膜互扩散系数与液膜厚度的比值。用电子计算机求算了随交换剂组成变化的积分粒内互扩散系数。     

用于聚合物溶液扩散系数计算的活度系数模型比较

用40个聚合物溶液体系的实验数据,对三个有代表性的活度系数模型用于计算联系自扩散系数和互扩散系数的热力学因子的精度进行了比较,结果表明三个模型的精度相近,误差一般在20％左右。,因而本工作揭示了聚合物溶注保由自扩散系数计算与扩散系数的一个潜在问题。即由于活度系数模型计算热力学因子误差较大所带来的较大不确定性。     

纤维素基磁性聚偕胺肟树脂的研究——锌副族金属离子在树脂上的吸附

研究了Ｚｎ２＋、Ｃｄ２＋、和Ｈｇ２＋离子在碱式纤维素基磁性聚偕胺肟树脂（ＢＭＡＯ）上的吸附动力学。结果表明，吸附速度受粒内扩散所控制。测得粒内扩散系数分别是１．２２×１０－４、２．４２×１０－４和３．９０×１０－４ｃｍ２·ｓ－１；Ｈｇ２＋离子在树脂上的吸附行为符合Ｆｒｅｕｎｄｌｉｃｈ和Ｌａｎｇｍｕｉｒ等温吸附方程；浓集因数随Ｈｇ２＋离子浓度降低而上升，有利于从稀溶液中除去Ｈｇ２＋离子。将树脂加至Ｚｎ２＋、Ｃｄ２＋或Ｈｇ２＋离子浓度为５０ｐｐｍ的溶液中，离子去除率分别是９６．１、９９．９和９９．３％。     

INTRAPARTICLE DIFFUSION OF RARE EARTHS IN POROUS CATION EXCHANGERS

Experiments for determining cerium isotope ion exchange rates with macroporous resins Amberlyst 15,D001 and XN1010 are discribed.The kinetics of the isotope ion exchange reaction has been examined by a simple theoretical equation of intraparticle effective diffustivity De in a porous ion exchanger.The ion exchange proceedes by diffusion within the macropores and the solid phase of the resin,De of cerium was affected by the concentration of the bulk solution C and was separated into a macropore diffusivity D^-p and a solid phase diffusivity D^-g by the equation.The diffusion coefficients of the exchanging ion are shown to have the values in the macropores comparable with those in the bulk solution and to have the values in the solid phase comparable with those in gel resin with the same crosslinkage as the resins used for the experiments.     

DIFFUSIVITY OF RARE EARTH ION IN POROUS ION EXCHANGE RESINS

TheporousionexchangeresinshavebecomeanimportantreactivepolarermaterialwhicharewidelyappliedinindustrialoperationsHowever,afewstudi..[l--3]reportedtheintraparticlediffusivityofporousionexchangers.Theionexchangedisplacementprocessonporousresinbedforseparationofrareearthsistheoneofthebestwaystoenhancetheeffectivityofthismethod.TounderstandthediffusionoftheionintheresinisveryavailablefolimproVingtheprocess.EXPERIMENTAL1.Pre--experimentsAllthereagentsusedareA.R.grade.152'154Euisusedasaradiot…     

Phenol removal from aqueous solution by adsorption and ion exchange mechanisms onto polymeric resins

The removal of phenol from aqueous solution was evaluated by using a nonfunctionalized hyper-cross-linked polymer Macronet MN200 and two ion exchange resins, Dowex XZ (strong anion exchange resin) and AuRIX 100 (weak anion exchange). Equilibrium experimental data were fitted to the Langmuir and Freundlich isotherms at different pHs. The Langmuir model describes successfully the phenol removal onto the three resins. The extent of the phenol adsorption was affected by the pH of the solution; thus, the nonfunctionalized resin reported the maximum loading adsorption under acidic conditions, where the molecular phenol form predominates. In contrast both ion exchange resins reported the maximum removal under alkaline conditions where the phenolate may be removed by a combined effect of both adsorption and ion exchange mechanisms. A theoretical model proposed in the literature was used to fit the experimental data and a double contribution was observed from the parameters obtained by the model. Kinetic experiments under different initial phenol concentrations and under the best pH conditions observed in the equilibrium experiments were performed. Two different models were used to define the controlling mechanism of the overall adsorption process: the homogeneous particle diffusion model and the shell progressive model fit the kinetic experimental data and determined the resin phase mechanism as the rate-limiting diffusion for the phenol removal. Resins charged after the kinetic experiments were further eluted by different methods. Desorption of nonfunctionalized resin was achieved by using the solution (50% v/v) of methanol/water with a recovery close to 90%. In the case of the ion exchange resins the desorption process was performed at different pHs and considering the effect of the competitive ion Cl⁻. The desorption processes were controlled by the ion exchange mechanism for Dowex XZ and AuRIX 100 resins; thus, no significant effect for the addition of Cl⁻ under acidic conditions was observed, while under alkaline conditions the total recovery increased, specially for Dowex XZ resin.     

弱碱性阴离子交换树脂的本征解离常数

根据Donnan膜平衡模型及外推法提出弱碱性阴离子交换树脂本征解离常数的测定方法。并测得大孔丙烯酸系弱碱性阴离子树脂D705的本征解离常数的负对数pK_b~(int)为3.72士0.04,结果表明,Marinsky在测弱酸性阳离子树脂的pK_a~(int)时,引入交换剂相中H~+及Na~+的活度系数相等的假定并非必要。     

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     

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.     

模拟磷矿脱镁废水中镁离子的交换动力学研究

用动边界模型积分方程描述模拟磷矿脱镁废水中Mg2＋在001×7×7型树脂上的有限浴交换动力学,得到了动力学总方程.Mg2＋的交换过程属颗粒扩散控制,表观活化能为23.45 kJ•mol－1,Mg2＋的表观反应级数为0.68.     

Application of Br-82 as a radioactive tracer isotope to study bromide ion-isotopic exchange reaction in strongly basic anion exchange resin Duolite A-161

In the present investigation Br-82 radioactive isotope was used as a tracer to study the kinetics of exchange reaction taking place between the ion exchange resin and the 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 on to the ion exchange resin (forward reaction), or from the ion exchange resin in to the solution (reverse reaction), the two ion-isotopic exchange reactions should occur simultaneously, which was further confirmed from the values of specific reaction rate 0.122 and 0.123 min⁻¹ respectively obtained under identical experimental conditions. The radioactive tracer technique employed in the present investigation will be useful for characterization of various industrial grade ion exchange resins.     

离子交换树脂在分析化学中的应用

简要评述了离子交换树脂在分析化学中的应用。包括离子交换树脂预富集技术从稀溶液中浓缩痕量离子,离子交换树脂相分光光度法测定微量离子,离子色谱在无机分析中的应用,以及离子交换树脂在有机分析与生化分析中的应用。