Macroporous Cation Exchange Resin Research Articles

Selective Removal of Cu(II) Ions by Using Cation-exchange Resin-Supported Polyethyleneimine (PEI) Nanoclusters

A novel hybrid adsorbent D001-PEI was fabricated for selective Cu(II) removal by immobilizing soluble polyethyleneimine (PEI) nanoclusters within a macroporous cation exchange resin D001. Negligible release of PEI nanoclusters unexpectedly observed during operation may result from the porous cross-linking nature of D-001 as well as the electrostatic attraction between PEI and D001. Increasing solution pH from 1 to 6 results in more favorable Cu(II) retention by D001-PEI, and Cu(II) adsorption onto D001-PEI follows the Langmuir model and the pseudosecond-order kinetic model well. Compared to the host cation exchanger D001, D001-PEI displays more preferable adsorption toward Cu(II) in the presence of competing Mg(2+), Ca(2+), Sr(2+) at greater levels in solution. Fixed-bed adsorption runs showed that Cu(II) sequestration on D001-PEI could result in its conspicuous decrease from 5 mg/L to below 0.01 mg/L. Also, the spent hybrid adsorbent can be readily regenerated by 6-8 BV HCl (0.2 mol/L)-NaCl (0.5 mol/L) binary solution for repeated use with negligible capacity loss. The results reported herein validate that D001-PEI is a promising adsorbent for enhanced removal of Cu(II) and other heavy metals from waste effluents.

Sorption of Ni(II) ions from aqueous solution by Lewatit cation-exchange resin

Ion-exchange is an alternative process for uptake of heavy metals from aqueous solutions. In the present study, the sorption of nickel(II) ions from aqueous solution was investigated by using Lewatit MonoPlus SP 112 (strongly acidic, macroporous cation-exchange resin) in a batch adsorption system as a function of pH (2.0–8.0), initial nickel concentration (50–200 mg/L), resin dosage (0.5–2.0 g/L), contact time (0.5–3 h), and temperatures (298–318 K). The data were analyzed on the basis of Lagergren pseudo-first order, pseudo-second order (Types 1–5), Elovich and external, Weber–Morris intraparticle, pore–surface mass diffusion models. The experimental data showed that the maximum pH for efficient sorption of nickel(II) was 6.0. At the optimal conditions, nickel(II) ions sorption on the resin was decreased when the initial metal concentration increased. The results indicated that the resin dosage strongly affected the amount of nickel(II) ions removed from aqueous solution. The adsorption process was very fast due to 80% of nickel(II) sorption was occurred within 30 min and equilibrium was reached at about 90 min. Freundlich and Langmuir adsorption isotherm models were used for sorption equilibrium data and the maximum adsorption capacity (171 mg/g) of Lewatit MonoPlus SP 112 was obtained from Langmuir isotherm. The thermodynamic parameters (Δ G°, free energy change; Δ S°, enthalpy change; and Δ H°, entropy change) for sorption of nickel(II) ions were evaluated. The rise in temperature caused a partly increase in the value of the equilibrium constant ( K c) for the sorption of nickel(II) ions. Moreover, column flow adsorption study was also studied. Breakthrough curves were obtained from column flow studies by using both synthetic solution and rinsing bath water of filter industry. The column regeneration was carried out for two sorption–desorption cycles. The eluant used for regeneration of the cation-exchange resin was 7% (w/w) HCl. The experimental results demonstrated that Lewatit MonoPlus SP 112 cation-exchange resin could be used effectively for the removal of nickel(II) ions from aqueous medium.

Trimerization of isobutene over cation exchange resins: Effect of physical properties of the resins and reaction conditions

Oligomerization of isobutene has been investigated using several cation exchange resins in order to produce triisobutenes that are useful feedstock for heavy alkylates and neo-acids. Trimers selectivity increases with increasing isobutene conversion. High isobutene conversion is obtained at high temperature and low space velocity by using macroporous cation exchange resins that have high concentration of sulfonic acid groups. Under selected conditions (viz., isobutene WHSV: 10 h −1; temperature: 70 °C; catalyst: Amberlyst-35), the isobutene is quantitatively oligomerized with higher than or equal to 70% selectivity for trimers. The wet resin catalysts containing water or ethanol are very stable for the oligomerization up to about 70 h contrary to the gradual decrease in the conversion with dehydrated catalysts.

Selectivity engineering of 4-phenoxyacetophenone by acylation of diphenyl ether with ion exchange resins: modeling of catalyst deactivation and remedies

The synthesis of 4-phenoxyacetophenone, an important intermediate for the production of fine chemicals, was carried out via acylation of diphenyl ether with acetic anhydride using various solid acid catalysts, amongst which macroporous cation exchange resins were effective. The effects of various reaction parameters on the rate of reaction and selectivity were investigated to deduce the intrinsic kinetics of the reaction. However, the reusability studies demonstrated that the resin activity falls in subsequent reactions due to blocking of pores by larger products, particularly di-acylated derivatives rendering some pore networks ineffective. This could be modeled to extract both the rate constants and deactivation constants. A first-order model for independent deactivation was found to fit the data satisfactory. A strategy was then developed to increase the selectivity and reduce deactivation of catalyst.

雲門湖水中の溶存有機物の特性

Dissolved organic matter (DOM) in Lake Unmun (Korea) and its two inflowing rivers was fractionated using three resin adsorbents (XAD-8 resin, macroporous cation and anion exchange resins) into five classes : aquatic humic substances (hydrophobic acids), hydrophobic neutrals, hydrophilic acids, bases, and hydrophilic neutrals. The characteristics of DOM were investigated by evaluating DOM fraction distribution, ultraviolet ray absorbance of DOM fractions (UV absorbance at 260nm), and molecular size distribution of DOM. Aquatic humic substances (AHS) and hydrophilic acids (HiA) were found to be predominant in both lake and river waters. In particular, AHS were greater in percentage fraction than HiA. The UV to dissolved organic carbon (DOC) ratio (UV/DOC ratio) of AHS was two times higher than that of HiA. The UV/DOC ratios of the total DOM, AHS and HiA were 12.9-32.8, 7.2-29.4 and 5.3-17.1 [m ABS cm-1·l·g C-1], respectively. The molecular weight distribution of the lake water DOM was determined by high-pressure size exclusion chromatography and found to exhibit a relatively narrow size range and low weight-averaged molecular weights ranging from 1,010 to 1,110 g·mole-1.

Etherification of dimethylbutenes in excess methanol

Oxygenated compounds such as ethers produced by the reaction of alcohols and alkenes have good potential for use as performance and environmental enhancing additives for transportation fuels. In this study, the production of the C 7 ether, 2,3-dimethyl-2-methoxybutane (DM2MB), was investigated in a batch reactor from 323–343 K at high methanol concentrations. A macroporous cation exchange resin, Amberlyst 15, was employed as catalyst for the etherification of 2,3-dimethyl-1-butene (DM1B) and 2,3-dimethyl-2-butene (DM2B) with methanol. Kinetic rate constants were correlated by fitting the experimental data to kinetic equations based on a pseudo-homogeneous model. Experimental results were obtained for the effects of temperature on simultaneous etherification and isomerization of DM1B and DM2B and differences in the reactivities of the two alkenes were noted. Kinetic and equilibrium parameters obtained from the Arrhenius and Van't Hoff equations agreed well with values obtained from similar studies in the literature.

Electrodeionization 1: Migration of Nickel ions absorbed in a rigid, Macroporous Cation-exchange Resin

The removal of nickel ions from a packed bed of ion-exchange material under an applied potential is studied. This process involves the use of an electrodialysis type cell in which the centre compartment is filled with a packed bed of ion-exchange particles. The bed width, concentration of nickel in the resin and electrolyte concentration were varied. Emphasis was placed on the rate of nickel migration, current efficiency and the effective mobility of nickel in the system. The purpose of the study is to aid in the development of a system for the continuous removal of heavy metal ions from dilute solutions.

Synthesis of α,ω-dicarboxypropyl oligodimethylsiloxanes by ion-exchange resin catalyzed equilibration polymerization

A series of α,ω-dicarboxypropyl oligodimethylsiloxanes of predetermined molecular weights was synthesized from octamethylcyclotetrasiloxane, D 4, and 1,3-bis-(3-carboxypropyl)tetramethyldisiloxane (BCPTMDS) by a heterogeneously catalyzed equilibration polymerization reaction using a macroporous cation-exchange resin as an acidic catalyst. The structure of the obtained linear oligomers was verified by IR, 1H- and 13C-NMR spectroscopy, while their molecular weights were determined by 1H-NMR spectroscopy, vapor pressure osmometry, functional group analysis and gel permeation chromatography. It was shown that the expected target molecular weights, ranging between 600 and 3500, were achieved with a satisfactory accuracy.

Separation of Thorium from Uranium Product at the Tail End of Thorium Fuel Reprocessing Using Macroporous Cation-Exchange Resin

The utility of macroporous cation-exchange resins for the separation of uranium from thorium (relevant to the final purification of the product uranium after reprocessing of the thorium breeder fuel) was examined. Two such cation-exchange resins were studied and compared with a previously used gel-type resin. Batch experiments and column experiments were performed to generate equilibrium data and to optimize the procedure for the separation of U from Th under process conditions. Recovery and purity of the final product were the same while loading and washing rates were much higher (120 mL/h) than those used for gel-type resins (40 mL/h). Much higher throughput was achieved without losing product quality when macroporous resins were used instead of the gel-type resin.

Reaction of ethanol and formaldehyde: use of versatile cation-exchange resins as catalyst in batch reactors and reactive distillation columns

Diethoxymethane was prepared in batch mode as well as in continuous Reactive Distillation Column (RDC) from ethanol and aqueous formaldehyde in the presence of a macroporous cation-exchange resin Indion-130. The batch reaction was studied for the effect of catalyst loading, mole ratio, concentration, temperature, etc. A pseudo homogeneous model was used to explain the batch kinetics and the kinetic parameters were evaluated. In the case of RDC, the effect of various parameters such as residence time, reflux ratio, mole ratio, feed concentration, feed configuration, etc. on the conversion and product purity was studied and evaluated.

Acetalization of Formaldehyde with Methanol in Batch and Continuous Reactive Distillation Columns

Methylal, an important raw material and a solvent, is produced by acetalization of aqueous formaldehyde with methanol. This acetalization reaction was carried out in a closed system in the presence of a cation-exchange resin Indion 130 as catalyst and was found to be equilibrium limited. In order to increase the conversion for this reaction, reactive distillation was carried. Batch reactive distillation was performed in the presence of the cation-exchange resin Indion 130 as catalyst. Continuous reactive distillation was performed in a reactive distillation column (RDC) using three different types of catalyst packing. The first type of catalyst packing was coarse size macroporous cation-exchange resin Indion 130, which was directly packed along with Raschig rings. The second type of catalyst packing was Indion 130 tied in cloth bags. The third type of catalyst packing used was a silica-supported organic catalyst. Up to 99% conversion of formaldehyde was achieved by reactive distillation. Vapor−liquid equi...

Removal of Alkaline Catalysts from Polyols by Ion Exchange: Selection of an Ion-Exchange Resin

Abstract Polyols, as commercially prepared, contain in their crude form various impurities such as alkali metal hydroxides which were employed as catalysts for their production. Most practical methods for removing these impurities involve acid neutralization of the alkali to form insoluble salts which are removed by filtration. A variety of commercial resins were evaluated in this work as ion exchangers for the purification of polyols. Amberlite 252, a macroporous cation exchange resin, was found to be the best resin. The loaded resin was regenerated efficiently. The results suggest that such a process is both technically and economically feasible.

Separation of traces and larger amounts of bismuth from gram amounts of thallium, mercury, gold and platinum by cation-exchange chromatography on a macroporous resin

Traces and larger amounts of bismuth (up to 50 mg) can be separated from gram amounts of thallium, mercury, gold and platinum (up to 5 g) by sorption from a mixture of 0.1 M hydrochloric acid and 0.4 M nitric acid on a column containing just 3 g (8.1 ml) of AGMP-50, a macroporous cation-exchange resin. This resin retains bismuth much more strongly than does the usual microporous resin (styrene-DVB with 8% cross-linkage). Other elements are eluted with the same acid mixture as that used for sorption, and bismuth is finally eluted with 1.0 M hydrochloric acid. Separations of bismuth are sharp and recoveries quantitative. Only microgram amounts of the other elements remain in the bismuth fraction. Amounts of bismuth as little as 5 μg have been separated from 5 g of thallium, and determined (r.s.d. = 2%) by flame atomic-absorption. Only 100-μg amounts of bismuth have been separated from gram amounts of mercury, gold, and platinum, but there is no reason to believe that smaller or larger amounts of bismuth cannot be separated from these elements and recovered with the same accuracy as that for the separation from thallium. The lower limit of the method is determination of 0.4 μg of bismuth in 10 ml of solution (0.004 absorbance). An elution curve, the relevant distribution coefficients and the results of analysis of synthetic mixtures and two practical samples [thallium metal and mercury(II) nitrate] are presented.

Methyl tertiary butyl ether formation in a catalytic bed reactor — kinetic and modelling study

Synthesis of methyl tertiary butyl ether (MTBE) using methanol and isobutene was studied using macroporous cation exchange resin, Amberlyst 15 in the hydrogen form, as a catalyst in the temperature range 328–348 K. The reaction was carried in a fixed bed catalytic reactor operated at atmospheric pressure with liquid methanol and gaseous isobutene. The effects of weight hourly space velocity (WHSV) catalyst particle size and reaction temperature were studied. The reaction rates increased with an increase in reciprocal space velocity and reaction temperature. Interparticle diffusional effects were absent under experimental conditions. The reaction rate data were interpreted using a heterogeneous model based on Langmuir— Hinshelwood kinetics. The reaction enthalpy was also calculated from kinetic analysis and was found to be compatible with the thermodynamic value. A Langmuir—Hinshelwood—Hougen—Watson (LHHW) rate model fitted kinetic data well.

A Semi-Automated Bone Pretreatment System and the Pretreatment of Older and Contaminated Samples

A semi-automated continuous-flow system used to process archaeological bone to purified gelatin or amino acids for 14C dating is described. Powdered bone is retained in flow cells specifically designed to permit the sequential leaching of the bone with acid, alkali and water. Crude collagen obtained by this process is gelatinized, and than either purified directly using a macroporous cation exchange resin (BioRad AGMP-50), or hydrolyzed and the amino acids desalted on BioRad 50W-X8 resin. When compared with previous methods used by the laboratory, the new method allows more samples to be treated to a higher degree of purification. Examples of dates obtained on “standard” bones are presented, and confirm that no contamination is introduced from the components used in the new process.

Distribution coefficients and ion-exchange selectivities for 46 elements with a macroporous cation-exchange resin in hydrochloric acid-acetone medium

Distribution coefficients with the macroporous cation-exchange resin AG MP-50 in HCl-acetone mixtures ranging from 0.2 to 4.0 M HCl and from 0 to 95% acetone have been determined for 46 elements. The ion-exchange behaviour of the elements is discussed, some possible separations are indicated, and elution curves demonstrating separations of the combinations Au(III)BiZnPbSr; Rh(III)InGaCuNi and CdFe(III)LiAlYb are presented.

COMPARATIVE DISTRIBUTION COEFFICIENTS FOR SOME ELEMENTS WITH A MACROPOROUS CATION EXCHANGE RESIN IN HNO3AND HCl

ABSTRACT Cation exchange equilibrium distribution coefficients are presented for the chloride complex forming elements Hg(II), Bi(III), In, Cd, Pb(II), Fe(III), Ga, Zn, Cu(II) and Te{IV) with a macroporous (macroreticular) cation exchange resin in nitric acid of concentrations ranging from 0.20 to 5.00 M.Known distribution coefficients (from the literature) for similar concentrations of hydrochloric acid are included for comparative purposes and the influence of chloride complex formation is discussed. Separations which are possible by using both HC1 and HNO3 as eluting agents are demonstrated by two elution curves separating the mixtures Hg(II)-Bi(III)-Zn-Pb(II); and Tl(III)-Bi(III)-Cu(II)-Fe(III).

Liquid phase synthesis of methyl tert‐butyl ether catalyzed by ion exchange resin

AbstractSynthesis of methyl tertiary butyl ether (MTBE) from methanol and isobutene was studied using macroporous cation exchange resin, Amberlyst 15 in the hydrogen form, as a catalyst in the temperature range of 313‐328 K. The reaction was carried out in a batch reactor at a pressure of one atmosphere in the liquid phase. A high degree of agitation was maintained in order to eliminate film diffusion resistance. The effect of catalyst loading, catalyst particle size and reaction temperature on reaction rate were studied. The reaction rate increased with increase in catalyst concentration and reaction temperature. Resin particle size had virtually no effect on the rate under the experimental conditions.The reaction rate data were analysed using homogeneous kinetics and heterogeneous models based upon Langmuir‐Hinshelwood rate expressions. The apparent activation energies using homogeneous and heterogeneous models were determined and found as 79.0 kJ/mol and 76.7 kJ/mol respectively.

Influence of structure of sulfonated cation exchange resins on their catalytic activity in alkylation of phenol by olefins

The catalytic activity of the resins was evaluated from results obtained in alkylation of phenol by n-nonene and n-decene. The contents of olefins, phenol, sec-alkyl phenyl ethers, o- and p-sec-alkylphenols, and dialkylphenols in the alkylated products were determined by gas-liquid chromatography. The effect rate constant of alkylation was calculated on the basis of a second order equation. The influence of pore characteristics of sulfonated cation exchange resins was generalized on their catalytic selectivity. Optimal activity and selectivity of catalytic action in the alkylation of phenol by higher olefins were exhibited by macroporous cation exchange resins of the KU-23(10/60) type.

Sulfo cation-exchange resins as heterogeneous catalysts for the reaction of styrene with formaldehyde

1. Macroporous and gel sulfo cation-exchange resins are active catalysts for the condensation of styrene with formaldehyde. The product, 4-phenyl-1,3-dioxane was obtained in up to 97% yield. 2. The activity of macroporous sulfo cation-exchange resins increases with decreasing particle diameter but in the case of the gel samples, granule size has only a slight effect on the reaction rate. 3. The enhanced activity of sulfo cation-exchange resins is presumably a result of the high value of the acidity function Ho of the sulfonic acid groups of the cation-exchange resin.