Polymers with Tethered Anionic and Cationic Groups as Membranes for Fuel Cells

Ionic clustering, water binding, and ion conductivity were studied in polymers functionalized with sulfonic acid and quaternary ammonium hydroxide groups. Small-angle x-ray scattering showed that no clustering occurred in the quaternary ammonium containing anion exchange membranes, while evidence of ionic clusters was present in both sulfonated poly(phenylene) and in Nafion, a poly(perfluorosulfonic acid). Interestingly, the water self-diffusion coefficients of the anion exchange membranes were generally greater than those observed for the sulfonated poly- (phenylene)s, and moreover, the water self diffusion coefficients in anion exchange membranes were not a strong function of diffusion time. The water binding behavior lead to increased normalized conductivity in anion exchange membranes as compared to proton exchange membranes at the highest ion exchange capacities.     

New Method for Simultaneous Arsenic and Selenium Speciation Analysis in Seafood and Onion Samples

This paper presents a new method for the simultaneous speciation analysis of arsenic (As(III)-arsenite, As(V)-arsenate, DMA-dimethylarsinic acid, MMA-methylarsonic acid, and AsB-arsenobetaine) and selenium (Se(IV)-selenite, Se(VI)-selenate, Se-Methionine, and Se-Cystine), which was applied to a variety of seafood and onion samples. The determination of the forms of arsenic and selenium was undertaken using the High-Performance Liquid Chromatography Inductively Coupled Plasma Mass Spectrometry (HPLC–ICP–MS) analytical technique. The separation of both organic and inorganic forms of arsenic and selenium was performed using two analytical columns: an anion exchange column, Dionex IonPac AS22, containing an alkanol quaternary ammonium ion, and a double bed cation–anion exchange guard column, Dionex Ion Pac CG5A, containing, as a first layer, fully sulfonated latex for cation exchange and a fully aminated layer for anion exchange as the second layer. The ammonium nitrate, at pH = 9.0, was used as a mobile phase. The method presented here allowed us to separate the As and Se species within 10 min with a suitable resolution. The applicability was presented with different sample matrix types: seafood and onion.     

SYNTESIS OF THE COMPLEXES OF MACROPOROUS SULFONATED RESINS WITH FERRIC CHLORIDE AND THEIR CATALYTIC BEHAVIOR FOR SETERIFICATION OF ACETIC ACID WITH BUTANOL

The complex resins prepared from macroporous sulfonated resin D72(H^+ form) with ferric chloride or ferric chloride hexahydrate have both sites of Bronsted acid and Lewis acid.In the catalysis of exterification of acetic acid with butanol the complex resins show to have much higher catalytic activity than that of its matrix.a conventional sulfonated cation exchange resin D72.     

INTERACTION OF AMINO ACID WITH ION EXCHANGE RESIN Ⅲ.FURTHER INVESTIGA TION OF SUPEREQUIVALENT ADSORPTION MECHANISM OF AMINO ACID ON ION EXCHANGE RESIN

The adsorption isotherms of glycine,alanine and oxidized glutathion on strong acid cation and strong base anion exchange resins from aqueous solutions were measured and the superequivalent adsorptions of glycine and alanine observed.The infrared spectra of glycine adsorbed on the cation and the anion exchange resins,001×7 and 201×7,were measured.From these results,it is concluded that the amino acid adsorption on the ion exchange resin proceeds not only through ion exchange and proton transfer mechanisms,but also through aminecarboxylate interaction between the adsorbed amino acid molecules,and the formation of second layer of amino acid molecules is the mechanism of superequivalent adsorption of amino acid,the carboxylate or amine groups of the first layer of amino acid molecules on the ion exchange resin act as the exchange sites for the second layer of amino acid molecules.     

Polymer-anchored platinum complexes as catalysts for the Baeyer–Villiger oxidation of ketones: preparation and catalytic properties

The preparation of a variety of catalysts obtained by ion exchange of the complex [(dppb)Pt(μ−OH)]₂²⁺ with sulfonated styrene–divinylbenzene copolymers is reported. Copolymers used are commercial ion exchange resins containing either 4% or 20% DVB and they were loaded with either Li⁺ or NBu₄⁺ prior to exchange with the Pt complex. Metal loading in the heterogenized catalysts is in the range 2–8% by weight. Their catalytic properties in the Baeyer–Villiger oxidation of methylcyclohexanone with hydrogen peroxide appear to be best in terms of activity and productivity either in neat ketone or in EtOH as the solvent. The use of commercial resins with high exchange capacity prevents the use of DCE as the solvent, i.e., the optimum conditions for the homogeneous system, thereby leading to activities and productivities that are generally lower than their homogeneous counterpart. A discussion on the influence of the philicity properties of the support with respect to the performance of the catalyst is reported.     

胺基修饰的高度交联聚苯乙烯树脂对间苯二酚吸附行为研究

研究了AH系列胺基修饰的超高交联树脂对水溶液中间苯二酚的静态吸附行为特征,结果表明,它们对间苯二酚的吸附容量明显高于母体交联树脂NDA-100和大孔弱碱性阴离子交换树脂D301.AH系列树脂与吸附质分子之间不仅有范德华作用力,还存在着氢键等作用力.该类树脂对间苯二酚的吸附为自发的放热过程,属于以物理作用为主兼有弱化学作用的吸附过程.吸附速率符合准一级动力学方程,表观吸附速率常数随树脂胺基含量的升高而降低.     

Sulfoacylated poly(styrene-divinylbenzene) copolymers as resins for cation chromatography. Comparison with sulfonated, dynamically coated and silica gel cation exchangers

Most important properties of an ion chromatographic resin are influenced by the resin matrix, the type of functional group and the ion-exchange capacity. Highly crosslinked PS-DVB resins of 5 microm diameter have been functionalized by sulfoacylation, by sulfonation and by dynamic coating over a wide range of exchange capacities. These materials allow a study of the influence of different ion-exchange sites and capacities. The influence of the degree of functionalization on resin performance is completely reverse for sulfoacylated and sulfonated resins. The HETP values for all observed analytes (Cu, Pb, Zn, Ni, Co, Cd, Mn, Ca, Mg) in a tartaric acid elution system decrease for sulfoacylated resins with increasing capacity, for sulfonated resins with decreasing capacity. The performance of sulfoacylated exchangers is better than for dynamically coated ones and far better than for sulfonated resins. The performance of silica gel based cation-exchangers such as BioSil CAT is in most cases better than observed for sulfoacylated resins.     

A mechanistic study of the reaction between furfural-acetone resins and polyamines

We have studied the reactions of furfural-acetone resins and their main components, i.e., monoand difurfurylidene acetones, with aliphatic polyamines and organic acid anhydrides. It is shown that furfural-acetone resins can be hardened under the action of polyamines and do not react with acid anhydrides. probable mechanism of the reaction with polyamines is proposed.     

硫酸根型阴离子交换树脂法改善PAC絮凝性能的研究

体系以聚合氯化铝溶液为原料，以硫酸型强碱性阴离子交换树脂为载体，进行离子交换反应。结果表明，在保持氧化铝含量基本不变的情况下，能有效地提高聚合铝的碱化度。同时生成含ＳＯ４＾２－的聚合氯化铝，实验证明它的絮凝效果优于了聚合氯化铝。     

Heterogeneous ion-exchange membranes

The field of heterogeneous ion exchange membranes is reviewed briefly. Specific advantages and disadvantages of heterogeneous ion exchange membranes are discussed compared with those of homogeneous ion exchange membranes. p]The development of heterogeneous ion exchange membranes is presented in historical perspective. The electrochemistry of ion-selective membranes began with Ostwald in 1890. After the classical work of Michaelis (1925) with collodion membranes, the first fully synthetic ion exchange membranes were prepared by Zhukov (1933) and Wassenegger (1940), based on sulfonated phenol—formaldehyde resins. These initial membranes, which were of the homogeneous type found no practical uses. The era of commercially useful ion exchange membranes began with the work of Wyllie (1948), Juda (1950), Bodamer (1953) and their collaborators who prepared heterogeneous ion exchange membranes by embedding ion exchange particles into polymer matrices. p]Methods for making heterogeneous ion exchange membranes include compression-molding of polymer powders, compounding on hot rolls, latex or solvent blending in situ generation of either the matrix or the ion exchange material. Microheterogeneous ion exchange membranes can be made from block and graft copolymers, interpolymers snake-cage resins, similar techniques and materials. p]Even though the first commercial ion exchange membranes were heterogeneous, the interest in this type of membranes subsided later. As polymer science progressed, speciality monomers and polymers were being made which opened the way to the preparation of quite sophisticated homogeneous ion exchange membranes of satisfactory mechanical strength. However, the possibilities of heterogeneous ion exchange membranes are by no means exhausted and this field may warrant further exploration, applying modern methods and materials and thus progressing beyond the relatively crude heterogeneous ion exchange membranes of the pioneer times.     

Abstraction of basic compounds by sulfonated polymeric resins in capillary gas chromatography

A small amount of a lightly sulfonated non-porous resin placed in the liner of the injection splitter of a gas chromatograph retains basic organic compounds but allows neutral compounds to be chromatographed normally. The organic bases in the gaseous state react with sulfonic acid groups on the resin surface to form protonated ions. Abstraction of bases is complete at a base: neutral molar ratio as high as 200:1 and a large number of samples can be injected before the sulfonated resins need to be replaced.     

离聚物共混体系在溶液中分子间缔合的粘度研究

研究了磺化聚苯乙烯离聚体／聚（苯乙烯 ４ 乙烯吡啶）共混体系、磺化聚苯醚离聚体／聚（苯乙烯 ４ 乙烯吡啶）共混体系和磺化聚苯醚离聚体／胺化聚苯醚共混体系在氯仿／甲醇混合溶剂中的粘度行为，结果表明，和它们分别对应的不含离子基的共混物相比，这三个共混体系都表现出较高的比浓粘度．这是由于体系中的酸基及其盐和含氮碱基的引入，在共混组分间产生了强烈的离子相互作用，从而导致分子间的缔合，使比浓粘度提高．并讨论了溶剂体系、功能基种类及共混组分的主链结构等因素对这种分子间缔合作用的影响．     

硫酸根型阴离子交换树脂法改善PAC絮凝性能的研究

体系以聚合氯化铝溶液为原料、以硫酸型强碱性阴离子交换树脂为载体， 进行离子交换反应．结果表明，在保持氧化铝含量基本不变的情况下，能有效 地提高聚合铝的碱化度。同时生成含ＳＯ_４~（２－）的聚合氯化铝（简称ＰＡＣＳ），实验证明它的絮凝效果优于聚合氯化铝（简称ＰＡＣ）．     

Exchange characteristics of monocarboxylic acids and monosulfonic acids onto anion-exchange resins

In the previous paper (N. Kanazawa, K. Urano, N. Kokado, Y. Urushigawa, J. Colloid Interface Sci. 238 (2001) 196), the equilibria of propionic acid and benzoic acid adsorption onto three anion-exchange resins were investigated, and an equation was proposed that summed of the physical adsorption of the carboxylic acid molecule and the ion exchange of the dissociated carboxylate ion. The ion exchange equation, including a selectivity coefficient to chloride ion for each combination between carboxylate ions and anion-exchange resins, could be used in wide ranges of concentration and pH. In this research, ion-exchange equilibria using 16 anion-exchange resins and 9 organic acids including monocarboxylic and monosulfonic acids were investigated. It could be confirmed that the proposed equation applied to the ion exchange with these monoorganic acids. Characteristics of ion exchange between the organic anions and anion exchange were also studied by the selectivity coefficients.     

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.     

两性树脂与水处理

两性树脂可简单地分为两大类：一类是不能形成内盐的，其性能与阴和阳离子交换树脂的混合物相近。另一类则能形成内盐，并由此产生了一系列新的特性，这类树脂的选择性，膨胀性及吸附容量等在一定范围内都随溶液中电解质浓度提高而提高＾〔２〕，因此可适用于浓电解质溶液的分离提纯。本文重点论述了形成内盐的一些规律性，尤其是树脂的交联度和功能基性质以及环境条件如温度，浓度和ｐＨ等与形成内盐的关系。     

Uptake of alkanes and alcohols by ion-exchange resins in aqueous solution.

Uptake of alkane (C5-C9) and alcohol (C4-C7) solutes by both strong acid cation exchange resins and strong base anion exchange resins in aqueous medium has been studied. The amount of solute taken up by resins is directly proportional to the solute concentration equilibrium with resins. Hydrophobic interaction between the solute and the resin matrix appears to play an important role in the uptake phenomenon.     

An atomic absorption spectrophotometric method for the determination of trace amounts of zinc in canned juices after ion exchange separation

An atomic absorption spectrophotometric method is described for the determination of microgram quantities of zinc in canned juices. After sample digestion in concentrated nitric acid, the solution is evaporated till near dryness, and then a solution of 2 M HCl is added to form tetrachlorozincate (II) ion. This acid solution, containing the zinc complex is passed through an ion-exchange column (anion exchange resin, chloride form, which is preconditioned by passing 1 M HCl solution). Zinc is eluted from the column with 0.01 M HCl solution. After evaporation to dryness, the residue is dissolved in 1% (v/v) HNO3, and then atomized into an air-acetylene flame. The limit of detection of the method is 0.15 micrograms ml-1 Zn. The analytical aspects of the proposed method, including the standard addition technique are discussed.     

Utilization of ion exchangers in analytical chemistry XXVI : Application of the ion-exchange method to solutions containing oxidants

The free acid form of a cation-exchange resin of the sulfonated hydrocarbon type (Dowex 50) can be used for a quantitative liberation of the corresponding acids from salt solutions containing oxidants that are reduced by phenolic resins. Positive results have been obtained with solutions containing bromate, iodate, periodate, molybdate, and chromate. With permanganate a partial reduction occurs which prevents the application of the ion-exchange method for quantitative separation of solutions containing permanganate.     

Heterogeneous ion-exchange membranes based on sulfonated poly(1,4-phenylene sulfide) and linear polyethylene: preparation, oxidation stability, methanol permeability and electrochemical properties

Poly(1,4-phenylene sulfide) was sulfonated with chlorosulfonic acid in 1,2-dichloroethane. The product (IEC = 2.38 mequiv./g) was ground and sieved (mesh size 63 μm) to obtain small particles. The particles and linear polyethylene were mixed in various ratios and the resulting blends were press-molded at 150 °C to obtain the membranes. Membranes containing up to 66 wt.% of sulfonated particles could be prepared without any problem in mechanical strength. The membranes were characterized by their stability in oxidative environment, ionic conductivity, and diffusive permeability to methanol. The membrane containing 66 wt.% of sulfonated particles was almost as conductive as Nafion 117; it exhibited, however, much lower diffusive permeability to methanol. In a strongly oxidative environment (3% aqueous H₂O₂ at 70 °C), the prepared membranes were less stable than Nafion 117, but much more stable than membranes with sulfonated poly(styrene-co-divinylbenzene) particles. In preliminary laboratory tests with H₂/O₂ and direct methanol fuel cells, the prepared membranes with high concentrations of sulfonated particles performed similarly to Nafion 117.