Adsorption characteristics of thorium on silica-based anion exchange resins

To isolate and separate thorium from nitric acid solutions, three silica-based anion exchange resins were synthesized. Batch experiments were carried out to investigate adsorption behavior of thorium in nitric acid solutions. Adsorption at different concentrations of nitric acid and thorium, influence of contact time and coexisting metal ions, and effect of NO3– were investigated in detail. It was found that at high HNO3 concentrations,the resins exhibited higher adsorption capacity and better affinity towards thorium. The adsorption kinetics could be described by the pseudo-second order model equation, while the adsorption isotherms were well correlated by the Langmuir model. The maximum capacity towards thorium species on SiPyR-N4 was evaluated at 27–28 mg/g-resin. The thermodynamic parameters indicated the adsorption was an exothermic reaction. The presence of NO3– was found to promote the retention of the thorium species.

THE EFFECT OF IONIC STRENGTH ON THE UPTAKE OF TAURINE ON A STRONG-BASIC ANION EXCHANGE RESIN

Studied the effect of ionic strength on the uptake of taurine on a strong-basic anion exchange resin The batch phase equilibrium experiments of taurine on the anion exchange resin D290 were conducted at different ionic strength, and then the amounts of uptake of taurine on the resin at different pH were determined. The ion exchange mechanisms of taurine on the anion exchange resin at different pH were discussed. Experimental results showed that with increase of the ionic strength of solution, the adsorbed amount of taurine on the resin D290 decreased; Adding small amounts of NaOH or HCl into the system of taurine aqueous solution/D290 anion resin would nfake the amount of taurine taken up on the resin to decrease due to the competition uptakes of hydroxyl ion with taurine or the decrease in the amount of absorbable zwitterions of taurine in the solution and excluding the cations of taurine from the anion resin.

Exchange Reaction Characteristics of Anion Exchange Resin for Diclofenac Sodium

Aim To study the exchange reaction characteristics of anion exchange resin for diclofenac sodium. Methods The drug-resin complexes were prepared by a batch method with diclofenac sodium as the model drug and the strong anion exchange resin (201 × 7) as the carrier. The effects of different forms (OH~ - and Cl~ - ) of the strong anion exchange resin, the particle size of the resin, and the reaction temperature on the exchange behavior were described. The exchange kinetic profiles were fitted. The related exc...

A New and Original Method to Produce Ca(OH)<SUB>2</SUB>Nanoparticles by Using an Anion Exchange Resin

Ca(OH)2 nanoparticles in hydro-alcoholic dispersion (nanolime) were successfully employed in Cultural Heritage conservation, thanks to the ability to overcome the limiting aspects of traditional lime treatments. Nanolime were currently produced by chemical precipitation process, at high temperature, with long times of synthesis, and after several purification steps to remove undesired secondary phases. In this paper, an innovative, simple and original method for nanolime production was described. The method was based on an ion exchange process between an anionic resin and a calcium chloride aqueous solution, operating at room temperature. A pure Ca(OH)2 nanoparticles suspension can be rapidly obtained after separating the resin from suspension, and any purification step was necessary. The exhausted resins can be regenerated and reused for a cyclic nanolime production. Structural and morphological features of the produced nanolime were preliminarily characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Moreover, XRD measurements allowed estimating nanoparticles reactivity by following their carbonatation process in air, in relation to different water/alcohol ratios and medium or high relative humidity conditions. The produced Ca(OH)2 nanoparticles appeared hexagonally plated, with dimension less than 100 nm and, compared with those obtained by typical wet precipitation method, they proved to be more reactive.

A New Method for Preparation of Anion Exchange Resins Based on Crosslinked Polvstvrene

This paper presents a new method for preparing anion exchange resins based on crosslinked polystyrene which consists in the acylation of crosslinked polystyrene by FriedelCrafts reaction followed by reductive amination. Aminated resins are quaternized to formcorresponding strong base anion exchange resins. The method avoids the use of carcinogenic chloromethyl methyl ether which is widely used in the preparation of commercial anion exchange resins.

A more precise method to evaluate kinetic leakage of anion exchange resin used in condensate polishing of power plant

Sulfate mass transfer coefficient(MTC) is a sensitive parameter to evaluate the kinetic leakage of anion exchange resin used in condensate polishing system of thermal and nuclear power plant.However,a sufficiently precise determination method has not been well established.In this paper,the final expression of sulfate MTC derived based on plug flow reactor model is the same as Harries' model,which is widely acknowledged in this field.In the determining system we constructed,in-situ calibration of the concentration of sulfate and its cation conductivity was conducted and sulfate MTCs of four typical strongly basic anion exchange resin samples were determined.The systematic error is 8.26% and the calibrated curve used for quantifying sulfate is obtained.The repeatability and reproducibility standard deviation are 0.05×10^(-4) m·s^(-1) and 0.07×10^(-4) m·s^(-1) respectively,which are lower than previous works.By controlling test condition accurately,this study has developed a more precise sulfate MTC determining method.This method provides a basis for further research.

Isolation of Uranium by Anionic Exchange Resins

A separation methodology to isolate natural uranium from its radioactive daughters： Th, Ra, Bi, Pb, Pa and Po, was developed using an only one anion exchange resin and varying concentrations of HC1 solutions. Three types of anion exchange resins were tested and the separation process was followed by gamma and alpha spectrometry. Uranium can be quantitatively isolated from its descendants using Dowex IX8 （20-50 mesh） or Amerlite IRA （100 mesh） resins in three steps： using 4 and 8 mol/L-1 HCI and water to recover uranium. The method is easy, quick, and inexpensive.

A STUDY ON THE KINETICS OF EXCHANGE REACTIONS OF W（Ⅵ） OR Mo（Ⅵ） WITHIN MACROPOROUS ANION EXCHANGE RESIN（D290） PHASE

The exchange behaviors of WO_4￣(2-) MoO_4￣(2-), H_2 W_(12) O_(40)￣(6-) and Mo8 O_(26)￣(4-) anions within macrOPorous exchange resin (D290) phases have been studied.The values of diffusion constant (B), inner diffusion coefficient (D), retarted time (td) half - exchange-period (t1/2), and activation energy (△E) were found from the kinetic analyses. A new method to separate W(Ⅵ) and Mo (Ⅵ) from each other was also suggested.

Effect of dissolved organic matter on nitrate-nitrogen removal by anion exchange resin and kinetics studies

The effects of dissolved organic matter （DOM） on the removal of nitrate-nitrogen from the model contaminated water have been investigated utilizing the strong base anion exchange resins. With the increase of gallic acid concentration from 0 to 400 mg/L, the adsorption amount of nitrate-nitrogen on the commercial resins, including D201, Purolite A 300 （A300） and Purolite A 520E （A520E）, would significantly decrease. However, the presence of tannin acid has little impact on nitrate-nitrogen adsorption on them. Compared to D201 and A300 resins, A520E resin exhibited more preferable adsorption ability toward nitrate-nitrogen in the presence of competing organic molecules, such as gallic acid and tannin acid at greater levels in aqueous solution. Attractively, the equilibrium data showed that the adsorption isotherm of nitrate-nitrogen on A520E resin was in good agreement with Langmuir and Fretmdlich equations. The rate parameters for the intra particle diffusion have been estimated for the different initial concentrations. In batch adsorption processes, nitrate-nitrogen diffuse in porous adsorbent and rate process usually depends on t1/2 rather than the contact time. The pseudo first- and the second-order kinetic models fit better for nitrate-nitrogen adsorption onto A520E resin. The observations reported herein illustrated that A520E resin will be an excellent adsorbent for enhanced removal of nitrate-nitrogen from contaminated groundwater.

C-410树脂分离富集-电感耦合等离子体质谱法测定地质样品中的金、铂、钯

研究了地质样品中超痕量Au、Pt和Pd的测定方法。采用C 4 1 0阴离子交换树脂在 1 .5mol LHCl条件下对Au、Pt、Pd的吸附率分别为 91 .2 %、1 0 0 .0 %、95 .7%。共存离子除Ge4+ 、Cr6 + 、Ti4+ 外 ,无显著性干扰。用ICP MS测定Au、Pt、Pd的检出限分别为 0 .2 7、0 .4 0和 0 .1 9μg L。当n =8时 ,Au的RSD为 1 9.2 % ;Pt的RSD为 2 8.1 % ;Pd的RSD为 1 5 .6%。

DT-1016型阴离子交换树脂分离富集金铂钯

研究了DT - 1 0 1 6型阴离子交换树脂对超痕量Au、Pt、Pd的吸附性能及条件。在0 .0 2 5mol/LHCl介质中 ,流出速度为 0 .5～ 1 .0mL/min时 ,Au、Pt和Pd的富集效果最佳 ,吸附率分别为 99.72 %、99.60 %和 97.95 % ,共存离子无显著性影响。用等离子体质谱测定标准物质中Au、Pt和Pd ,其结果与标准值基本相符。检出限Au为 0 .2 7μg/L ,Pt为 0 .40 μg/L ,Pd为0 .1 9μg/L。对GBW 0 72 94铂族元素国家标准物质进行精密度试验 ,RSD(n =8)Au为 1 9.2 % ,Pt为 2 8.1 % ,Pd为 1 5 .6%。

利用D-900树脂对巴戟天多糖脱色工艺进行优化

研究D-900阴离子交换树脂对巴戟天多糖的最佳脱色工艺。采用D-900阴离子交换树脂对巴戟天多糖进行静态和动态吸附试验,考察不同温度、树脂用量、流速和pH值等因素对吸附过程的影响,以脱色率和多糖保留率综合评价其脱色效果。最佳工艺参数为:采用动态吸附,柱溶液温度45℃、流速1.0BV/h、上样液pH6.0。使用D-900阴离子交换树脂对巴戟天多糖脱色可以获得较好的脱色率以及较高的多糖保留率。

717型阴离子交换树脂分离富集-光度法测定铜精矿和尾矿中微量钼

研究了717型阴离子交换树脂柱分离-富集钼的条件,建立了光度法测定铜精矿和尾矿中微量钼的方法。在pH为7.5的条件下,钼以MoO42-形式被717型阴离子交换树脂定量吸附后,采用2mol/L HNO3和0.5mol/L NH4NO3混合溶液定量洗脱,消除了绝大部分共存离子的干扰。通过树脂柱分离-富集后,用硫氰酸钾分光光度法测定钼的检出限为5.6μg/L,相对标准偏差(RSD)为2.2%(n=5),加标回收率在96.2%～105.7%之间,实际样品测定结果与ICP-AES方法测定值基本一致。

树脂分离-氢化物发生-原子荧光光谱法测定食品中无机砷、一甲基胂和二甲基胂

建立了用阴离子交换树脂分离-氢化物发生原子荧光光谱法测定食品中无机砷、一甲基胂和二甲基胂的方法。分别从样品上样条件及二甲基胂、一甲基胂、As(Ⅲ)和As(Ⅴ)分离条件进行了优化。研究了树脂处理程序对分离的影响,并探讨了共存离子对测定砷的干扰和消除的方法。对方法的适用范围做了研究。本方法具有操作简便、快速、灵敏度高等优点。检出限(以砷计)分别为:无机砷0.34μg/L,一甲基胂0.57μg/L,二甲基胂0.46μg/L。

离子交换-双氧水氧化法制备纳米CeO_2晶体

以99.995%Ce(NO3)3和强碱性阴离子交换树脂为原料,采用离子交换-双氧水氧化法合成制备出纳米CeO2晶体。并就离子交换反应中的Ce3+浓度、树脂加入速度和离子交换温度及H2O2加入速度等条件对CeO2粒径的影响进行了探讨,得出了离子交换-双氧水氧化法制备纳米CeO2晶体的最佳工艺条件。FTIR、TEM分析表明,离子交换法无需对合成的Ce(OH)3溶胶进行洗涤即可去除NO3-、CO32-等阴离子杂质,并用H2O2将该溶胶氧化,经真空干燥可制得粒径分布均匀,平均晶粒尺寸约3nm,高纯度的CeO2粉体。

离子交换树脂-原子荧光光谱法测定三七中的4种形态砷

目的建立分析三七中的有毒砷形态的方法。方法应用水-盐酸将三七中的形态砷原样提取后,采用阴、阳离子交换树脂成功分离了4种形态砷,无机的As(Ⅲ)、As(Ⅴ)和有机的一甲基砷酸(MMA)、二甲基砷酸(DMA)。再用氢化物发生原子荧光光谱仪,对各形态砷进行测定。结果砷在0.5～40μg/L范围内呈良好线形关系,方法的检出限为As(Ⅲ)0.20μg/L;DMA 1.25μg/L;MMA 1.14μg/L。相对标准偏差为无机砷〔As(Ⅲ)+As(Ⅴ)〕6.68%,As(Ⅲ)8.01%,As(Ⅴ)13.42%,MMA13.95%,DMA2.71%,回收率无机砷As(Ⅲ)90.30%～92.24%,As(Ⅴ)88.27%～90.91%,MMA88.18%～90.82%,DMA90.54%～101.41%。结论该方法克服了现行三七标准中将有机砷混入无机砷的缺点。

Fe(Ⅲ)-硫氰酸盐-吐温80配合物在阴离子交换树脂上的吸附及其应用

利用７１７型阴离子交换树脂吸附Ｆｅ（Ⅲ）－硫氰酸盐－吐温８０配合物，配合物最大吸收峰位于波长４８１．４ｎｍ，表观摩尔吸光系数为１．０６×１０５Ｌ·ｍｏｌ－１·ｃｍ－１，Ｆｅ（Ⅲ）量在０～８００μｇ／Ｌ服从比尔定律，建立了相应Ｆｅ（Ⅲ）的固相分光光度法，应用于高纯稀土中痕量铁的测定，结果满意。

717型阴离子交换树脂分离富集-萃取光度法测定金精矿和尾矿中金

研究了717型阴离子交换树脂柱分离和富集金的条件,建立了光度法测定金精矿和尾矿中金的方法。在10%(体积分数)盐酸介质中,金以AuCl形式被树脂定量吸附后,采用10mL 60g/L的硫脲溶液洗脱吸附在树脂上的金和用过氧化氢破坏洗脱液中过量硫脲,以结晶紫萃取分光光度法测定洗脱液中金。金精矿和尾矿中可能存在的4种阴离子和17种阳离子对金的测定没有干扰。方法的检出限为0.43μg/L,矿样的测定结果与活性碳预富集-原子吸收法相吻合,金精矿和尾矿测定结果的相对标准偏差(n=5)分别为5.4%和7.2%。

离子交换富集-火焰原子吸收光谱法测定卷烟辅料中镉

研究了用强阴离子交换柱富集和分离,火焰原子吸收光谱法测定卷烟辅料中镉,试样用微波加热消解。方法的相对标准偏差小于3．5％,标准回收率在96％～104％之间。

弱碱性阴离子交换树脂富集ICP-AES测定环境水体中Cr(Ⅵ)和有机态Cr(Ⅲ)的研究

选用331弱碱性阴离子交换树脂,对微污染水体中的Cr(Ⅵ)和有机态Cr(Ⅲ)进行了分离富集作用研究,考察了酸度、富集时间、洗脱液类型、洗脱液浓度及溶液中共存离子对分离富集过程的影响。研究表明,分别用1.0 mol.L-1HCl和2.0 mol.L-1NH4NO3+0.5 mol.L-1NH3.H2O可以很好分步洗脱有机态Cr(Ⅲ)和Cr(Ⅵ),利用ICP-AES测定,该方法对Cr(Ⅲ)和Cr(Ⅵ)的检出限分别为1.1和1.4μg.L-1,相应的相对标准偏差RSD(n=6)平均值分别为3.8%和5.6%。该方法适用于自来水、地下水、地表水及生活污水中痕量Cr(Ⅵ)和有机态Cr(Ⅲ)的分离富集及测定。