Weak base polystyrene anion exchangers I. Relation between their structure and sorption of methyl orange

Weak base anion exchangers with mono- and diethanolamine groups were obtained from styrene-divinylbenzene copolymers. The influence of the kind of inert diluent present in the suspension copolymerization system on the sorption properties of the anion exchangers derived therefrom in relation to methyl orange dye has been discussed. At constant anion exchange capacity the sorption properties were found to decrease with an increase in the gel heterogeneity. It has also been found that an increase of the process temperature brings about an increase in the degree of sorption, but the pseudoequilibration time was not affected.     

Sorption of aromatic compounds on macroporous anion exchangers based on polyacrylamide: Relation between structure and sorption behavior

The sorption of phenol, p-toluenesulfonic acid (p-TSA), Na-p-toluenesulfonate (Na-p-TS), 1,2-dihydroxy-3,5-benzene disulfonic acid disodium salt (Tiron), and 3-hydroxy-4(sulfonaphthyazo)-5,7-naphthalenedisulfonic acid trisodium salt (Poceau 4R) on the macroporus anion exchangers with acrylamide structural units (weak and strong basic anion exchangers) and on the ion exchangers with amidoxime groups were studied. The maximum specific sorption of p-TSA was almost identical with the total exchange capacity for both the weak and strong basic anion exchangers. The sorption of Na-p-TS is strongly related to the functional group structure of the anion exchangers, being significant on the strong basic anion excahngers. The maximum specific sorption of Tiron was higher tan the total exchange capacity of the strong basic anion exchangers because it is mainly dependent on the ionic exchange properties. The morphological characteristics influenced only the establishement rate of the sorption equilibrium. The sorption of Ponceau 4R, which has the highest molecular weight, is important on the strong basic anion exchangers with high permanent porosity. The sorption of the organic anions is also dependent on the number of the sulfonic groups. © 1995 John Wiley & Sons, Inc.     

A novel way to prepare anion exchangers based on crosslinked polystyrene

A novel method for preparing anion exchangers based on crosslinked polystyrene is proposed which comprises first acetylation of crosslinked polystyrene by Friedel-Crafts reaction, then reductive amination of acetylated products by Leuckart reaction. Aminated products, if desired, are readily converted to corresponding tertiary amino anion exchangers or optionally quaternized to form corresponding strong base, quaternary ammonium anion exchangers. The new method, overcome the toxic problem of classic chloromethylation process, is safe, economical and convenient. Received: 29 September 1997/Revised version: 4 November 1997/Accepted: 12 November 1997     

Relationships between the synthesis conditions and the characteristics of anion exchangers

Several macroporous styrene–divinylbenzene copolymers were prepared using different diluents. The copolymers were chloromethylated with monochlor methyl ether and aminated with N,N-dimethyl-2-hydroxyethylamine in order to perform strongly basic anion exchanger, type II. It was established that the network morphology of anion exchanger determines its ion-exchange rate. It was, also established, by means of transmission electron microscopy, that chloromethylation reaction led to the morphological changes in the macromolecular network of the copolymers.     

Acrylic weak‐base anion exchangers and their behaviors in the retention process of some heavy‐metal cations

Two macroporous acrylonitrile/10% vinyl acetate/10% divinylbenzene copolymers as beads were obtained by the aqueous suspension copolymerization of the three comonomers in the presence of toluene as a diluent, which was used in two different amounts. These copolymers were chemically modified by their reactions with ethylenediamine, diethylenetriamine, and triethylenetetramine in the presence of water when the aminolysis–hydrolysis reaction of the nitrile groups and the hydrolysis reaction of the acetate groups occurred. From these reactions, weak‐base anion exchangers with high ion‐exchange capacities, between 1.6 and 2.2 mequiv/mL and 6.5 and 10.5 mequiv/g, were obtained. For these anion exchangers, the behaviors in the retention processes of the Ni(II), Cd(II), and Pb(II) cations were evaluated with the bath method. All the resins exhibited retention properties, but the retained amounts of the metal cations differed as a function of the resin and cation nature. Thus, the resin from the reaction with triethylenetetramine of the copolymer obtained in the presence of a larger amount of toluene could be considered the most suitable sorbent for the three metal cations, especially for Ni(II). Its maximum retention capacity for this cation was 2.67 mequiv/g of dried resin. From the noncompetitive and competitive retentions was observed the following selectivity order: Ni(II) > Cd(II) > Pb(II). The retention took place by the chelating processes between the functional groups with the ligand role, especially free amine groups, and metal cations. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 930–938, 2005     

Modification of a few anion exchangers to electron exchangers

Three anion exchangers, namely, MFH, PVC-TP, and De-Acidite FF-IP (a commercially available strong base anion exchanger) were converted into a copper complex, and the resulting complex was preferably reduced with an alkaline solution of sodium hydrosulfite and studied for the redox properties.     

Retention of gallium ions from acidic solutions by pyridine strong‐base anion exchangers

Using the batch method, the retention of Ga(III) from HCl solutions by two gel‐type pyridine strong‐base anion exchangers containing 1‐methyl‐ or 1‐butyl‐4‐vinylpyridinium chloride structural units, called S₁ and S₂ resins, respectively, was studied. The influence of the HCl and Ga(III) concentrations as well as of the contact time between the resin and the liquid phase was investigated. The parameters, which characterize the retention process, were estimated using Langmuir and Freundlich isotherms. Both resins exhibited a higher affinity for gallium ions from a 6M HCl solution. According to Langmuir isotherms, maximum retention capacities of 44.44 and 60 mg Ga(III)/g dry resin for the S₁ and S₂ resins, respectively, were obtained. Freundlich isotherms provide additional proof for a higher affinity of the S₂ resin for Ga(III) from HCl solutions. It is clear that the substituent length increase on N⁺ atoms led to an increasing affinity of the pyridine strong base anion exchangers toward Ga(III). © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3440–3444, 2002     

Sorption equilibrium of Cr(VI) ions by strong base anion exchangers with pyridine structures

Chromate sorption on pyridine strong base anion exchangers with different functional groups (methyl, ethyl, and butyl groups), at the quaternary nitrogen atoms, was studied as a function of various initial concentrations (100–1500 mg Cr/L) and counterion type. The studied resins in the Cl^?[ form have higher Cr(VI)‐retention capacities than those in the SO form. The pyridine strong base anion exchangers showed a selectivity reversal for the sulfate and chromate anions compared to that of the commercial resins. The alkyl substituent length of the quaternary nitrogen atoms exerted a substantial influence on the Cr(VI)‐retention capacity values for the resins in the Cl^? form; the chromate anions preferred resins with methyl functional groups, that is, resins with a greater hydrophilic structure. For the resins in the SO form the length of the substituent at the quaternary nitrogen atom had only a negligible influence on their Cr(VI)‐retention values. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1957–1963, 2004     

A novel method to prepare magnetic polymer‐based anion exchangers and their application

Magnetic microspheres with ion‐exchange features were prepared by applying a swelling and penetration process using polystyrene–divinylbenzene‐based anion‐exchange resins as starting materials. The polymeric anion‐exchange particles were swollen with an aqueous solution of N‐methyl‐2‐pyrrolidone, followed by incubation with superparamagnetic iron oxide nanoparticles to allow them to penetrate into the swollen particles. The pH value in the solution of magnetic nanoparticles could significantly influence the uptake of magnetic nanoparticles by the swollen anion‐exchange particles. Higher amounts of magnetic nanoparticles entrapped within anion exchangers could be achieved at pH 10–12. An increase in the concentration of magnetic nanoparticles led to a higher density of magnetic nanoparticles entrapped within the interior of anion exchangers and, thus, higher magnetization of the magnetic anion exchangers. Loading of the magnetic nanoparticles onto the exchanger had no effect on anion‐exchange functionality. The utility of the resulting magnetic anion‐exchange resins was demonstrated for the isolation of plasmid pEGFP‐C1 from Escherichia coli cell lysates. The magnetic anion‐exchange microspheres could be easily collected within a few seconds in a magnetic field. Thus, automation of the protocol for DNA isolation using these magnetic anion‐exchange resins has a high potential. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40725.     

Studies of sorption of Pd(II) microquantities on strongly basic polyacrylate anion exchangers

The sorption of palladium(II) microquantities from a chloride and chloride-nitrate (V) model 0.1-6.0 M HCl, 0.1-0.9 M HCl-0.9-0.1 M HNO₃, 1.0 M ZnCl₂-0.1 M HCl and 1.0 M AlCl₃-0.1 M HCl systems on strongly basic polyacrylate anion exchangers was studied. The research was carried out by means of dynamic and static methods. The recovery factors of Pd(II) were determined from the static studies. The working ion-exchange capacities as well as weight and bed distribution coefficients of Pd(II) were calculated from the breakthrough curves. The commercial strongly basic anion exchangers of the functional quaternary ammonium groups — Purolite A-850 and Amberlite IRA-958 — can be used in recovery technologies of Pd(II) from anodic slime, wastewaters and spent catalysts due to their high selectivity.     

Preparation and characterization of anion exchangers from petroleum asphaltites

The chloromethylation reaction of an asphaltite and styrene graft copolymer followed by the amination of the chloromethylated products was optimized. New strongly basic anion exchangers with an exchange capacity of 2.5 mg-equiv/g and a mechanical strength of 93% were prepared.     

Sorption of perrhenate anions by lignin anion exchangers

The sorption of rhenium ions on high-permeability lignin ion exchangers was studied. The effects of the nature of functional groups in anion exchangers, the concentrations of the metal and an acid in solution, the pH of solution, and the time of sorption on recovery parameters were found. Conditions for the efficient separation of perrhenate ions from model sulfate solutions were determined. It was found that the new fibrous ion exchangers based on the natural polymer lignin were superior to AN-21, AN-18, and AV-16 synthetic anion exchangers based on the amino copolymers of styrene and divinylbenzene, which are commonly used for the sorption of rhenium ions, in sorption and kinetic characteristics.     

Sorption of palladium (II) chloride complexes on weakly, intermediate and strongly basic anion exchangers

The precious metals and their alloys are extensively applied in refineries and the chemical and electronic industries as well as in medicine. Their small amounts in nature and extensive exploitation from natural resources are a serious obstacle as far as their application is concerned. High prices of palladium favour its recovery from recyclable materials and industrial wastes. Ion-exchange chromatography is one of the physicochemical methods of noble metal ion recovery. A study was done on the possibility of selective removal of palladium (II) microquantities from the model 0.1-6.0 M HCl, 0.1-0.9 M HCl-0.9 - 0.1 M HNO₃, 1.0 M ZnCl₂ - 0.1 M HCl and 1.0 M AlCl₃-0.1 M HCl systems on weakly, intermediate and strongly basic anion exchangers. The sorption research of Pd (II) on various types of anion exchangers was carried out by means of dynamic and static methods. The working ion-exchange capacities, weight and bed distribution coefficients were calculated from the breakthrough curves of palladium (II) ions. From the static studies the recovery factors of Pd (II) depending on the anion exchanger-solution contact time in the model systems under discussion were determined.     

Desorption of rhenium from weakly basic anion exchangers

The desorption of rhenium from an A172 anion exchanger with an ammonia solution has been studied. A172 and A170 anion exchangers have been investigated with infrared spectroscopy. The difference in their structures has been revealed so that A172 can be assigned to a medium basic anion exchanger type. The reason for the low desorption of rhenium from the A172 anion exchanger has been determined.     

Adsorption of anionic textile dye Acid Green 9 from aqueous solution onto weak or strong base anion exchangers

The aim of this work is to study the thermodynamic and kinetic studies with regard to the adsorption of Acid Green 9 (AG9) on the most efficient resin, namely, acrylic weak base anion exchange resin with ethylenediamine‐functional groups (A1) selected from several anion exchange resins. The influence of the various experimental parameters such as, pH, initial dye concentration, contact time, temperature, and adsorbent dose was investigated by batch experiments. The extent of the dye adsorption increased with the decrease of the initial dye concentration and the increase of the contact time, temperature, and amount of the adsorbent. Adsorption process was quantitative and very fast at low concentrations of the dye. To investigate the mechanism of the adsorption and potential rate‐controlling steps, pseudo first‐ and second‐order, as well as intraparticle diffusion kinetic equations have been used. The adsorption kinetic of AG9 dye from aqueous solution onto A1 could be described by the pseudo second‐order reaction model. The obtained results are in agreement with the Langmuir and Freundlich models. In the optimum conditions established, an adsorption capacity of 500 mg textile dye (72% purity) g^?1 adsorbent (at 293 K) was reached. Desorption experiments by batch and dynamic methods were performed using a solution of 0.05 mol L^?1 NaOH. A series of 13 adsorption–desorption cycles were carried out by the dynamic method with a quantitative adsorption and the desorption efficiency higher than 95%. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Correlation between the porous structure of polystyrene and its discolouring ability

Porous polystyrene was prepared according to the following methods by variation of the production parameters: (A) Method based on the suspension polymerization using a nonsolvent of the polymer. (B) Method based on the dissolution of polystyrene in a solvent and then precipitation using a nonsolvent of the polymer. The molecular weight of the polymer, its structure using Hg-porosimetry, and the microscopic pattern of the polymer grains were determined. The ability of the produced polystyrene to discolour aqueous solutions of different dyes (mainly methylene blue) was also examined. From the correlation between porous structure and discolouring ability in comparison with corresponding discolouring examination of other adsorptive agents (activated carbon) the importance of the following parameters was found out and evaluated: (a) total value of pore volume or pore volume distribution, (b) intermediate part of pore distribution 10000 – 100 Å for the adsorption of the given dyes, (c) shape of pores, which are different in method A and B (the comparison of produced polystyrene by different production parameters should be done only by independent methods and not between A and B method). It also resulted that it is necessary to introduce appropriate groups into the molecules of the porous polystyrene in order to increase the adsorption rate of an ionic or a polar substance. In conclusion, by appropriate choice of the production parameters of porous polystyrene a product with the desired characteristics of porosity could be produced.     

非金属换热器及其应用

详细介绍了国外非金属换热器的种类、结构以及发展和应用现状。     

Sorption of organic compounds on strong basic macroporous anion exchangers

The behavior of various strong basic type II macroporous anion exchangers against the sorption of some organic acid alkaline salts as follows: natrium benzoate, natrium benzenesulfonate, potassium α-naphthylacetate, natrium β-naphthalenesulfonate, and natrium anthraquinone-2-sulfonate was established. The values of the sorption capacities depend on the morphology of anion exchanger network, the type and the size of organic anion, as well as the type of anion exchanger.