螯合剂负载树脂的研究及其应用

螯合剂负载树脂是一类新型螯合树脂,具有选择性好、制备方法简单等特点,近年来,这类树脂在分析化学中的应用受到人们的关注。本文概述了多年来有关螯合剂负载树脂吸附机理、稳定性、对金属离子的吸附行为、再生等基本性能的研究工作,并简要介绍了这类树脂的制备及其应用。     

聚合物铬（Ⅵ）氧化剂的制备及其对醇的氧化研究

通过离子交换分别制得强碱、弱碱树脂负载的聚合物馅（Ⅵ）试剂，并研究了其对不同结构醉的氧化性能及反应条件。     

负载氧化铁大孔树脂及其对巴戟天多糖平衡吸附的性质

采用XRD、FTTR以及ASAP2010表面分析仪对负载氧化铁颗粒的AB-8吸附树脂进行了表征,发现负载的氧化铁主要以α-Fe2O3形式存在;负载氧化铁的AB-8树脂孔径在5～25nm之间,比表面积达到550m2/g,较原AB-8树脂略有增加.采用静态吸附实验考察了负载氧化铁颗粒的AB-8吸附树脂在不同离子强度条件下对巴戟天多糖的吸附性能.结果表明,负载氧化铁后,AB-8树脂对巴戟天多糖的吸附量有显著增加,对分子质量范围在2000u左右的巴戟天多糖有明显选择性;较高的离子强度有利于巴戟天多糖在负载氧化铁颗粒的AB-8树脂上的吸附.     

聚合物铬（VI）氧化剂的制备及其对醇的氧化研究

通过离子交换分别制得强碱，弱碱树脂负载的聚合物铬（ＶＩ）试剂，并研究了其对不同结构醇的氧化性能及反应条件。     

交联聚异丁烯酸甲酯型负载树脂的孔结构与分离稀土性能的关系

本文报导异丁烯酸甲酯型负载树脂的交联度、致孔剂组成和含量对负载树脂孔结构的影响.结果指出,良溶剂和劣溶剂按一定比例混合作为致孔剂,可制备不同孔结构的树脂.致孔剂量增加,树脂表观比重减小,而比表面积、孔体积与平均孔径均增加.交联度从10％增加到35%,表观比重和比表面积增加,而孔体积与平均孔径减小.增加致孔剂所含良溶剂的比例,树脂的表观比重、比表面积增加,而孔体积与平均孔径减小.已制备一系列不同孔结构的2-乙己基膦酸单2-乙己基酯(P507)负载树脂,比较了它们分离La、Ce、Pr、Nd的性能.结果表明,适当孔结构的负载树脂用于萃取色层分离稀土元素具有优良的分离性能.     

纤维状负载双硫腙聚酰胺树脂对铅的吸附性能

将市售粉粒状聚酰胺树脂在低温下改性后再与二苯基硫卡巴腙(双硫腙)进行负载反应,制成纤维状负载双硫腙聚酰胺树脂。研究了柱层析操作条件下,该树脂对铅的选择性吸附分离方法。实验表明,在pH3～7的HCl介质中,改性负载聚酰胺树脂对铅的吸附性能很好,饱和吸附容量为9．56mg/g,树脂上的铅可用5％的中性EDTA溶液进行洗脱。结合原子吸收分光光度法测定,方法可用于环境样品中微量铅的富集分离和测定。     

金属离子负载修饰阳离子树脂在酯化反应中的研究

将催化精馏中常用作催化填料的强酸性阳离子交换树脂用金属离子负载修饰后，考察了树脂催化性能的改变及树脂结构对催化性能的影响。实验表明，经修饰后树脂的催化能力都高于原树脂，在不分水的情况下，合成乙酸乙酯时乙酸的转化率最高可达73％，具有很好的选择性，金属离子能与树脂的磺酸基团产生络合，提高了树指的催化性能，所形成的新酸中心不会被阳离子交换而失活。     

基于稀土分离的萃淋树脂制备与应用研究

萃取色层法被称为第二代萃取体系,相对于液-液萃取选择性分离效果更好,萃取剂溶解损失小,被应用于超高纯稀土的制备。萃取色层法的关键是萃淋树脂,决定萃淋树脂性能的关键因素是萃取剂/萃取官能团。按照萃取剂与支撑基底的作用方式不同,萃淋树脂可分为两类:一类是萃取剂通过物理作用负载在支撑物基底上,另一类则是具有萃取作用的官能团通过化学键悬挂在支撑基底上。以萃取剂/萃取官能团为主要切入点,综述了近十年来萃淋树脂的研究进展,阐述了萃淋树脂的制备方法,负载不同萃取剂/悬挂不同萃取官能团的萃淋树脂对RE3+的萃取行为、机制、饱和萃取容量及分离性能等。     

用ICP—AES研究茶碱负载树脂对银离子的吸附行为

采用浸渍法将茶碱负载子阳离子交换树脂上,制得茶碱负载树脂（ＴＣＲ）。在一定浓度的硝酸或氨水溶液中,茶碱负载树脂具有较好的化学稳定性。以ＩＣＰ－ＡＥＳ作为检测手段,考察了其对银离子的吸附性能。结果表明,ＴＣＲ在ｐＨ４～７范围内可定量吸附Ａｇ＾＋,２ｍｇ／ｍＬ硫脲－０．５ｍｏｌ／Ｌ ＨＮＯ３的混合溶液可作为银的良好解吸剂。该负载树脂对银的吸附容量大,选择性好,适用于痕量银的富集分离。     

膦吡啶钯树脂的制备及其催化加氢活性

由氯甲基化的聚苯乙烯—二乙烯苯树脂可制得溴吡啶甲基化聚苯乙烯树脂和二苯基膦吡啶甲基化聚苯乙烯树脂。将苯氰氯化钯和二苯基膦吡啶甲基化聚苯乙烯树脂反应可得负载化的加氢催化剂。考查了其对异丙叉丙酮加氢反应的催化性能。     

新显色剂对-二甲氨基偶氮氯膦的合成及其与钍显色反应的研究

合成了新显色剂对-二甲氨基偶氮氯膦,研究了它与Th(Ⅳ)的显色反应.结果表明:Th(Ⅳ)在0～30μg/25mL范围内与该试剂形成的配合物在674,612和538nm³个波长处吸光度绝对值之和与溶液中Th(Ⅳ)的浓度呈线性关系,故可利用该3个波长下吸光度绝对值叠加的方法测定Th(Ⅳ),其ε值达1.74×10⁵L·mol^-1·cm^-1.由于显色反应在较强酸性介质中进行,本法有良好的选择性,大多数共存离子不干扰钍的测定,用于测定岩矿中的微量钍,结果满意.     

Smart thorium and uranium determination exploiting renewable solid-phase extraction applied to environmental samples in a wide concentration range

A smart fully automated system is proposed for determination of thorium and uranium in a wide concentration range, reaching environmental levels. The hyphenation of lab-on-valve (LOV) and multisyringe flow injection analysis (MSFIA), coupled to a long path length liquid waveguide capillary cell, allows the spectrophotometric determination of thorium and uranium in different types of environmental sample matrices achieving high selectivity and sensitivity levels. Online separation and preconcentration of thorium and uranium is carried out by means of Uranium and TEtraValents Actinides resin. The potential of the LOV–MSFIA makes possible the full automation of the system by the in-line regeneration of the column and its combination with a smart methodology is a step forward in automation. After elution, thorium(IV) and uranium(VI) are spectrophotometrically detected after reaction with arsenazo-III. We propose a rapid, inexpensive, and fully automated method to determine thorium(IV) and uranium(VI) in a wide concentration range (0–1,200 and 0–2,000 μg L^-1 Th and U, respectively). Limits of detection reached are 5.9 ηg L^-1 of uranium and 60 ηg L^-1 of thorium. Different water sample matrices (seawater, well water, freshwater, tap water, and mineral water), and a channel sediment reference material which contained thorium and uranium were satisfactorily analyzed with the proposed method.     

Kinetic determination of uranium(IV) based on its catalytic effect on the phosphomolybdic acid-iodide reaction

A kinetic spectrophotometric method has been developed for the determination of trace amounts of uranium(IV) based on its catalytic effect on the phosphomolybdic acid iodide reaction. A significant feature of the proposed procedure is the selectivity for uranium(IV); it enables the determination of trace amount of uranium in the presence of large excess of rare metalions and other cations and anions. The method can be applied to the determination of uranium within the concentration range of 0–12μg· cm^?3, and the detection limit of the method is 0.02μg·cm^?3. Trace amounts of uranium in thorium nitrate and scandium oxide had been determined by the procedure and the results are satisfactory.     

Preparation and analytical properties of a chelating resin containing phenylalanine groups

A polystyrene-based macroreticular resin containing phenylalanine groups has been prepared and its analytical properties have been investigated and compared with Dowex A-1. The phenylalanine resin shows high selectivity for mercury(II) and copper(II) in the pH region 2-3. The sorption behaviour of copper has been examined in detail, with the intention of using the resin analytically. The important characteristics of the resin are fast equilibration, high selectivity and small volume change between its hydrogen form and metal forms. These enable it to be applied for the rapid concentration of trace amounts of copper in the presence of large amounts of diverse metals. It may be used for the determination of copper in sea-water and the separation of copper/cobalt and copper/nickel.     

Simultaneous spectrophotometric determination of trace amounts of uranium, thorium, and zirconium using the partial least squares method after their preconcentration by α-benzoin oxime modified Amberlite XAD-2000 resin

A new solid phase extraction method for separation and preconcentration of trace amounts of uranium, thorium, and zirconium in water samples is proposed. The procedure is based on the adsorption of U(VI), Th(IV) and Zr(IV) ions on a column of Amberlite XAD-2000 resin loaded with α-benzoin oxime prior to their simultaneous spectrophotometric determination with Arsenazo III using orthogonal signal correction partial least squares method. The enrichment factor for preconcentration of uranium, thorium, and zirconium was found to be 100. The detection limits for U(VI), Th(IV) and Zr(IV) were 0.50, 0.54, and 0.48 μg L⁻¹, respectively. The precision of the method, evaluated as the relative standard deviation obtained by analyzing a series of 10 replicates, was below 4% for all elements. The practical applicability of the developed sorbent was examined using synthetic seawater, natural waters and ceramic samples.     

Preparation and analytical properties of a chelating resin containing bicine groups

A polystyrene divinyl benzene based resin containing bicine groups has been prepared and its analytical properties investigated. The pH dependence of sorption of metal on the resin has been determined for Cu(II), Fe(II), Ni(II), Co(II), Zn(II), Hg(II) and Pb(II). The important characteristics of the resin are fast equilibrium, high selectivity and small volume change between its hydrogen and metal forms. These enable it to be applied to the rapid concentration of trace amounts of these metal ions. It shows promise for the separation of lead from other metal ions.     

Analytical procedure for the determination of thorium, zinc and potassium in diet samples

Instrumental neutron activation analysis (INAA), and atomic absorption spectrometry (AAS) have been used for the determination of trace amounts of thorium, zinc, and potassium in diet samples. Interlaboratory comparison has been made. The z-scores show that INAA can be used to determine thorium and zinc whereas AAS can be employed to determine potassium in diet samples.     

Functionalization of chitosan with 3-nitro-4-amino benzoic acid moiety and its application to the collection/concentration of molybdenum in environmental water samples

A chitosan resin functionalized with 3-nitro-4-amino benzoic acid moiety (CCTS-NABA resin) was newly synthesized for the collection/concentration of trace molybdenum by using cross-linked chitosan (CCTS) as base material. The carboxyl group of the moiety was chemically attached to amino group of cross-linked chitosan through amide bond formation. The adsorption behavior of molybdenum as well as other 60 elements on the resin was examined by passing the sample solutions through a mini-column packed with the resin. After the elution of the elements collected on the resin with 1 M HNO₃, the eluates were analyzed by inductively coupled plasma-mass spectrometry (ICP-MS) and atomic emission spectrometry (ICP-AES).

The CCTS-NABA resin can adsorb several metal ions, such as vanadium, gallium, arsenic, selenium, silver, bismuth, thorium, tungsten, tin, tellurium, copper, and molybdenum at appropriate pHs. Among these metal ions, only molybdenum could be adsorbed almost completely on the resin at acidic regions. An excellent selectivity toward molybdenum could be obtained at pH 3–4. The adsorption capacity of CCTS-NABA resin for Mo(VI) was 380 mg g⁻¹ resin. Through the column pretreatment, alkali and alkaline earth metals in river water and seawater samples were successfully removed.

The CCTS-NABA resin was applied to the adsorption/collection of molybdenum in river water and seawater samples. The concentrations of molybdenum in river water samples were found in the range of 0.84 and 0.95 ppb (ng g⁻¹), whereas molybdenum in seawater was about 9 ppb. The validation of the proposed method was carried out by determining molybdenum in the certified reference materials of SLRS-4, CASS-4, and NASS-5 after passing through the CCTS-NABA resin; the results showed good agreement with the certified values.     

Preconcentration and determination of ultra-trace amounts of U(VI) and Th(IV) using titan yellow-impregnated Amberlite XAD-7 resin

A simple and sensitive method for the determination of ultra trace amounts of U(VI) and Th(IV) ions by spectrophotometric method after solid-phase extraction on a new extractant-impregnated resin (EIR) has been reported. The new EIR was synthesised by impregnating a weakly polar polymeric adsorbent, Amberlite XAD-7, with titan yellow (TY) as extractant. The analytical method is based on the simultaneous adsorption of analyte ions in a mini-column packed with TY/XAD-7 and performing sequential elution with 0.5% (w/v) Na₂CO₃ for uranium and 2.0 M HCl for thorium. The influences of the analytical parameters including pH, salting out agent and sample volume were investigated. The interference effects of foreign ions on the retention of the analyte ions were also explored. The limits of detection for U(VI) and Th(IV) were as low as 50 and 25 ng L^?1, respectively. Relative standard deviations (n = 7) for U(VI) and Th(IV) were 3.1% and 2.9%, respectively. The method was successfully applied to the determination of ultra trace amounts of U(VI) and Th(IV) in different real matrices including industrial wastewater samples and environmental waters. The proposed method was validated using three certified reference materials and the results were in good agreement with the certified values.     

Preconcentration techniques for uranium(VI) and thorium(IV) prior to analytical determination-an overview

The need for the preconcentration of trace and ultratrace amounts of uranium(VI) and thorium(IV) in conjunction with various detection techniques was clearly brought out in the introductory part. Subsequently, various off-line and on-line procedures developed for uranium(VI) and thorium(IV) prior to their analytical determination since 1990 were critically reviewed in terms of enrichment factor, retention/sorption capacity, validation using certified reference materials and application to complex real samples. The relative merits and demerits of various preconcentration and/or separation of uranium(VI) and thorium(IV) prior to quantitation by a plethora of analytical techniques are discussed in concluding part of the review article.