Strong Anion Exchange Resin Research Articles

Adsorption Isotherms for Removal of Linoleic Acid from Ethanolic Solutions Using the Strong Anion Exchange Resin Amberlyst A26 OH

Adsorption isotherms for the removal of linoleic acid from aqueous ethanol were measured using a strong anion exchange resin (Amberlyst A26 OH). The data for linoleic acid were compared with previously published results for oleic acid. The equilibrium data were correlated using the Langmuir and Freundlich isotherms. Lower average deviations between experimental and calculated results were obtained with the Langmuir model. The capacity of the resin for adsorbing linoleic acid was evaluated at different water contents in ethanol, 100 w = 0.50 to 15.27, and at 298.15 K. The water content in ethanol does not influence significantly the equilibrium behavior, and the strong anion exchange resin has a good performance in the removal of linoleic acid from the liquid phase.

Determination of inorganic arsenic species in natural waters—Benefits of separation and preconcentration on ion exchange and hybrid resins

A simple method for the separation and determination of inorganic arsenic (iAs) species in natural and drinking water was developed. Procedures for sample preparation, separation of As(III) and As(V) species and preconcentration of the total iAs on fixed bed columns were defined. Two resins, a strong base anion exchange (SBAE) resin and a hybrid (HY) resin were utilized. The inductively-coupled plasma-mass spectrometry method was applied as the analytical method for the determination of the arsenic concentration in water. The governing factors for the ion exchange/sorption of arsenic on resins in a batch and a fixed bed flow system were analyzed and compared. Acidity of the water, which plays an important role in the control of the ionic or molecular forms of arsenic species, was beneficial for the separation; by adjusting the pH values to less than 8.00, the SBAE resin separated As(V) from As(III) in water by retaining As(V) and allowing As(III) to pass through. The sorption activity of the hydrated iron oxide particles integrated into the HY resin was beneficial for bonding of all iAs species over a wide range of pH values from 5.00 to 11.00. The resin capacities were calculated according to the breakthrough points in a fixed bed flow system. At pH 7.50, the SBAE resin bound more than 370 μg g −1 of As(V) while the HY resin bound more than 4150 μg g −1 of As(III) and more than 3500 μg g −1 of As(V). The high capacities and selectivity of the resins were considered as advantageous for the development and application of two procedures, one for the separation and determination of As(III) (with SBAE) and the other for the preconcentration and determination of the total arsenic (with HY resin). Methods were established through basic analytical procedures (with external standards, certified reference materials and the standard addition method) and by the parallel analysis of some samples using the atomic absorption spectrometry-hydride generation technique. The analytical properties of both procedures were similar: the limit of detection was 0.24 μg L −1, the limit of quantification was 0.80 μg L −1 and the relative standard deviations for samples with a content of arsenic from 10.00 to 300.0 μg L −1 ranged from 1.1 to 5.8%. The interference effects of anions commonly found in water and some organic species which can be present in water were found to be negligible. Verification with certified reference materials proved that the experimental concentrations found for model solutions and real samples were in agreement with the certified values.

A New Approach to Catalytic Degradation of Dimethyl Phthlate by a Macroporous OH-Type Strongly Basic Anion Exchange Resin

In the present study, a novel approach was developed to remove dimethyl phthalate (DMP), a representative phthalic acid ester (PAE) pollutant, from an aqueous solution using a macroporous OH-type strong base anion exchange resin D201-OH. As compared to the traditional catalyst aqueous NaOH, D201-OH displayed much higher catalytic efficiency for DMP hydrolytic degradation. Almost 100% of DMP was hydrolyzed to far less toxic phthalic acid (PA) in the presence of D201-OH, while only about 29% of DMP was converted to PA in the presence of NaOH under the identical amount of hydroxyl anions in the reaction system. More attractively, the hydrolysis product PA also can be simultaneously removed by the solid basic polymer D201-OH through a preferable anion exchange process, while NaOH induced hydrolysis products were still left in solution. The underlying mechanism for the hydrolytic degradation and simultaneous ion exchange removal process was proposed. Fixed-bed column hydrolytic degradation and ion exchange removal tests indicate that DMP can be completely converted to PA and subsequently removed from water without any further process, with pH values of the effluent being around 6 constantly. The exhausted D201-OH was amenable to an efficient regeneration by 3 bed volumes (BV) of NaOH solution (2 mol/L) for repeated use without any efficiency loss. The results reported herein indicated that D201-OH-induced catalytic degradation and removal is a promising approach for PAEs treatment in waters.

Reactive Ion Exchange Synthesis of Nano-ZnO and Its Photocatalytic Properties

Nano-crystalline ZnO particles were synthesized by a reactive ion exchange procedure using ZnSO4 and NaOH as precursors and a strong basic anion exchange resin as substrate. The precursors and ZnO samples were characterized by scanning electron microscopy, X-ray diffraction, and UV-Vis spectroscopy. The ZnO particles were club shape, and the synthesis process depended on the reactant concentration of ZnSO4 in the solution. The ZnO powders had high photocatalytic activity and stability for the gradation of methyl orange.

Study on Industrial Scale Chromatographic Separation Methods of Galactose from Biomass Hydrolysates

AbstractGalactose is an aldohexose, which has commercial uses in the pharmaceutical and food industries. Since monomeric galactose is not a freely occurring compound, it must be produced from galactose‐containing hydrolysates. This paper reports the results of experimental studies of the chromatographic separation of galactose in aqueous solutions by ion exchange resins on an industrial scale. Until now, galactose has only been determined from various solutions by liquid chromatography (HPLC) on an analytical scale. Chromatographic separation of galactose from carbohydrate mixtures was studied with strong acid cation exchange resins in Na+, Ca2+ forms and strong base anion exchange resin in SO42– form. The feed solutions were hydrolysates from three possible galactose sources: lactose, gum arabic and hemicellulose in spent sulfite liquor. The main monosaccharide impurities in these raw materials were glucose, arabinose, and xylose. It was demonstrated that large scale liquid chromatography can be used effectively for galactose separation from complex carbohydrate mixtures such as plant hydrolysates as well as lactose hydrolysate.

Ion exchange adsorption and elution for recovering gold thiosulfate from leach solutions

A new elution process for recovering gold thiosulfate from resins is described, and is based on the concept of synergistic ion exchange. In the presence of sulfite, Au(S 2O 3) 2 3− is converted to Au(S 2O 3)(SO 3) 3−, which has a reduced affinity for strong anion exchange resins and is shown to be readily eluted by weaker eluants, such as chloride. Chloride has several advantages over other systems: it is significantly cheaper and more stable than trithionate, and the return of chloride loaded resin to the adsorption circuit is less problematic than nitrate. Using the proposed chloride + sulfite system, the majority of the gold is stripped within 2 BV of elution, and the gold can be readily recovered from the concentrated eluate using electrowinning. The copper is pre-eluted using ammonium thiosulfate, with stripping of 99.7% of the copper, and only 2.7% of the gold. The new elution process was operated in closed loop with a continuous 7 stage adsorption mini-rig, and a solution gold grade of < 0.02 mg L − 1 is obtained within 6 tanks. The composite solution tail over 24 h is 0.005 mg L − 1 gold, indicating that the elution process produces a resin which is ideally suited for recycling without regeneration.

Characterization of peptides and proteins in commercial HSA solutions

HSA solutions account for 14% of the world market for plasma products. Albumin is indicated for reestablishing and maintaining circulatory volume in situations resulting from traumatic shock, surgery, or blood loss. Albumin is also used in extracorporeal liver support devices that perform blood dialysis against this protein. However, the protein composition of therapeutic albumin is only partially known. We performed an exhaustive analysis of albumin composition using a proteomic approach. Low abundance proteins and peptides in these samples were concentrated using a strong anion exchange resin. The absorbed material was eluted with a stepwise gradient of ammonium trifluoroacetate and the protein fraction was digested and analyzed by multidimensional liquid chromatography coupled to ESI-MS/MS using a linear ion trap. A total of 1219 peptides corresponding to 141 proteins different from albumin were identified with a false discovery rate <1%. Near 50% of these proteins have been described previously as forming part of the albuminome. Some of these proteins are proteases (kallikrein) or protease inhibitors (kininogen and SRPK1) or have relevant functions in cell surface adhesion (selectin, cadherins, and ICAMs) or in immunity and defense (molecules of the complement system and attractin). Characterization of these proteins and peptides is crucial in order to understand the therapeutic and possible deleterious effects of albumin therapies, in which this solution is infused to treat different pathological conditions.

N-methylimidazolium functionalized strongly basic anion exchanger: Synthesis, chemical and thermal stability

The synthesis and characterization of gel and porous strong base anion exchangers with N-methylimidazolium functional groups and the evaluation of their chemical stability in aggressive media and thermal behavior are reported. Strong base exchange capacity values, FT-IR spectroscopy as well as ESEM images proved the content of ionic groups and the morphology structure of the anion exchange resins. Both synthesized resins presented a very good chemical stability in hydrogen peroxide compared to the commercial strong base anion exchange resin, Amberlite IRA-400. It was also shown that the porous strong base anion exchange resin exhibited a better stability in aggressive media of high concentration than gel-type resin. The thermal stability of the samples was evaluated by dynamic thermogravimetric analysis in nitrogen gas. Comparing the TG and DTG curves it can be found that the degradation curves of the samples are close to each other in shape under the heating rate conditions. The differences for the samples between in the different heating rate are the typical temperatures and the residue rate of the decomposition.

Kinetics of Chromium Ion Removal from Tannery Wastes Using Amberlite IRA-400 Cl− and its Hybrids

A strong base anion exchange resin Amberlite IRA-400 Cl− and its hybrids with Mn(OH)2 and Cu(OH)2 are used for the removal of chromium from the synthetic spent tannery bath. The recovery is examined by varying the experimental conditions, viz., resin dosage, stirring speed, and temperature. The rate of chromium removal by Amberlite IRA-400 Cl− increased almost four times when the resin dosage was increased from 0.2 to 1.0 g. Furthermore, the rate of chromium sorption almost doubled when the stirring speed was increased from 100 to 1,000 rpm, suggesting that the sorption is a diffusionally controlled process. The chromium removal capacity also increased with the rise of temperature, showing the endothermic nature of the process. The results are explained with the help of film diffusion, particle diffusion, and Lagergren pseudo-first-order kinetic models. The kinetics results of the Amberlite IRA-400 Cl− are compared with its hybrid anion exchange resins IRA-400 Mn(OH)2 and IRA-400 Cu(OH)2. It is found that the hybrid ion exchangers have greater removal ability and fast kinetics as compared to the parent exchanger.

Simple and rapid analysis of aristolochic acid contained in crude drugs and Kampo formulations with solid-phase extraction and HPLC photodiode-array detection

Simple and rapid analysis of aristolochic acid (AA) in crude drugs and Kampo extracts using a solid-phase extraction method and HPLC-PDA analysis was investigated. Extraction of AA from samples was accomplished by adding methanol containing 1% ammonia. The addition of ammonia ionized the AA of acidic substances so that they adhered to an acrylamide copolymer of a strong anion exchange resin (Sep-Pak QMA) coupled to diol silica easily. Furthermore, a mixture of acetonitrile-water-phosphoric acid (75:25:2, v/v) was effective in isolating AA from its carrier. Since almost all interfering peaks originating from contaminants in crude drugs and Kampo extract formulations could be removed, a satisfactory HPLC chromatogram of AA was obtained. A good result was also obtained when Aristolochiaceae and crude drugs containing AA were tested. Particularly in the case of the medicinal parts of Asarum, several interfering peaks and a ghost peak detected near the AA peak were eliminated. The AA contents of two Kampo extract formulations, tokishigyakukagoshuyushokyoto and ryutanshakanto, were calculated by HPLC analysis. The AA content (the sum of AA-I and AA-II) was 1.25-6.13 mg per daily dose. From an additional recovery experiment for Kampo formulations, high recovery rates of AA were obtained. Neither LC/MS nor special instrumentation was necessary. Our results suggest that this simple, quick, and sensitive analytical method to detect AA in crude drugs and Kampo extract formulations would be valuable in safety inspections of AA in crude drugs and their products.

Effect of gamma radiation on organic ion exchangers

Effects of gamma radiation on indigenous strong cation and anion exchange resins have been studied in HCl medium up to a dosage of 3600 kGy. The ion exchange capacities of cation and anion exchangers decreased by around 20% at 2400 kGy of absorbed dose. Decrease in salt-splitting capacity and total exchange capacity for both cation and anion exchangers were comparable up to 2400 kGy. Above 2400 kGy, a marginal loss in the capacity was observed for cation exchangers whereas a drastic reduction was noticed for the anion exchangers. The distribution coefficients for zirconium, antimony and cobalt, measured in HCl medium, did not change significantly for 2400 kGy of absorbed dose. Crushing strength and moisture retention capacity did not exhibit any specific trend with the absorbed dose.

A Novel Chromatographic Production Scale Separation Process for L-Fucose

There is an increasing interest towards a special and very rare sugar, L-fucose, because of its functionalities, i.e., in the human body. There are only a few industrial production processes for L-fucose, and chromatographic separation of this valuable component from hemicellulose hydrolysates could be a feasible alternative. However, chromatographic separation of L-fucose with sufficient purity from other monosaccharides, especially deoxy sugars, has presented a problem in the state of the art. The aim of this work was to find a new process scale chromatographic purification method for L-fucose containing liquor. Of special interest was a process suitable for recovery of L-fucose from plant based biomass hydrolysate. This paper presents an industrial scale chromatographic separation method for the production of L-fucose. The use of a combination of strong and weak acid cation exchange resins increases L-fucose purity gradually, while the use of strong base anion exchange resin gives an excellent separation of L-fucose from other remaining sugar compounds.

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.

Removal of Cr(VI) onto functionalized pyridine copolymer with amide groups

New pyridine strong base anion exchange resin has been prepared by the nucleophilic substitution reaction of 4-vinylpyridine:divinylbenzene copolymer of gel structure with 2-chloroacetamide as halogenated compound. The resulting resin was used to remove Cr(VI) from the aqueous solution. Batch adsorption studies have been carried out to determine the effect of the initial concentration of Cr(VI), adsorbent dose, pH, temperature and the presence of sulfate anions as counter ions. The process was found to be pH, solid/liquid ratio and concentration dependent. The adsorption capacities increase with the increase of the initial concentration of Cr(VI) and therefore, the resin exhibited the degree of usage of the strong base exchange capacities higher than 90% and the good efficiency in the chromium removal. At acidic pH and low concentration of the hexavalent chromium the synthesized pyridine resin offer much greater chromate removal capacities compared to alkaline pH. Equilibrium modeling of the process of Cr(VI) removal was carried out by using the Langmuir and Freundlich isotherms. The experimental data obeyed these isotherm models. Thermodynamic studies were performed and the parameters namely, Δ G°, Δ H° and Δ S° showed the spontaneous and endothermic process of the adsorption of Cr(VI) on the pyridine resin. In the competitive adsorption studies, chromate/sulfate revealed the selectivity of the pyridine adsorbents towards chromium ions. This selectivity is explained by the adsorption of the transition metal anion on the π bonds of the pyridine ring and the formation a sandwich arrangement with chromium anion and amide functional groups attached to the quaternary nitrogen atoms.

Separation of the no-carrier-added 109Cd from Ag, Cu and 65Zn by use of a precipitation and AG1-X8 resin

The 109Cd radionuclide was produced in the cyclotron via natAg(p,n)109Cd reaction. The radiochemical separation of 109Cd from silver and non-isotopic impurities comprised of two stages. The optimum conditions of the 109Cd separation methods were: Ag precipitation with 0.015 M HCl and Cu and 65Zn by use of 0.015 M HCl on AG1-X8 strong anion-exchange resin. Chemical and radionuclidic purity of 109Cd were measured by ICP-AES and gamma-ray spectrometry respectively. Recovery yield and radionuclidic purity were obtained 99.7% and 99%, respectively.

Vapor Generation Atomic Absorption Spectrometric Determination of Cadmium in Environmental Samples with In-Line Anion Exchange Separation

A novel in-line anion exchange separation method is described for the removal of Mn(2+), Fe(3+), Ni(2+), Co(2+), Cu(2+), Zn(2+), and Pb(2+) from Cd(2+) and for its subsequent determination by vapor generation atomic absorption spectrometry. High Cd(2+) retention efficiency and maximum exclusion of other metal ions were achieved by using Cl(-), Br(-), or I(-) loaded strong base anion exchange resin and fiber in chloride medium. SO(4)(2-) and NO(3)(-) affected the retention of Cd(2+) on Cl(-) or Br(-) loaded exchangers but were beneficial for elution from I(-) loaded exchangers. Fast and efficient elution from the exchangers was achieved by using ethylenediamine solution. The removal of Zn(2+) was unnecessary as it prevents a decline in the sensitivity of cadmium response when ethylenediamine and high acid concentration were used. Under optimum conditions, the achievable detection limits (3sigma) with sample loadings of 0.48 and 9.6 mL were 40 ng L(-1) and 3 ng L(-1), respectively. Interference of residual organic matrix, in sample digests, with the separation and retention of cadmium were eliminated by use of microwave assisted digestion. The method was successfully applied to the determination of Cd in river sediment, fish liver, and water samples.

Studies concerning the anion exchange resins catalyzed esterification of epichlorohydrin with organic acids

The paper studies the esterification of carboxylic acids with epichlorohydrin over two macroporous strong base anion exchange resins with different polymer matrix. For both resins, the influence of reaction parameters (temperature, catalyst loading, molar ratio) on the reaction rate and the yields of the two isomeric esters were investigated.

L(+)-Lactic acid recovery from cassava bagasse based fermented medium using anion exchange resins

The properties of the ion exchange resins, Amberlite IRA 402, a strong anion exchange resin and IRA 67, a weak anion exchange resin were determined to evaluate their comparative suitability for lactic acid recovery from fermented cassava bagasse. Data on binding capacities and recovery proved that weak base resin in chloride form was the most favourable ones for lactic acid recovery from aqueous solutions and fermentation media. Fermented media obtained through simultaneous saccharification and fermentation of cassava bagasse starch hydrolysate based medium were used for lactic acid recovery study using weak base resin column. Amberlite IRA 67 had much more efficiency than Amberlite IRA 402 to recover lactic acid. Like in other reports, due to the presence of nutrients and ions other than lactate, the binding capacity was slightly lesser while using fermented media (~93%) instead of aqueous lactic acid solutions (~98%).

A Novel Method for the Production of Biodiesel from the Whole Stillage‐Extracted Corn Oil

AbstractThe extraction of corn oil from whole stillage and condensed distillers’ solubles (CDS) with hexane and its conversion to biodiesel were investigated. The analysis of the extracted oil showed 6–8 wt.% free fatty acid (FFA) in this oil. Acid, base, acid–base, and acid–base catalyzed transesterifications with intermediate neutralization with anion exchange resin were investigated. Experiments were performed with model corn oil substrates which contained 1.0–6.0 wt.% FFA. The effect of catalyst at 0.50–1.25 wt.% was studied at a 1:8 oil/methanol molar ratio. At 6.0 wt.% FFA concentration, the acid‐catalyzed scheme was slow and resulted in less than 20% yield after 4 h, while the base‐catalyzed was mostly consumed by the FFA and very little conversion was achieved. The acid–base catalyzed scheme succeeded in reducing the FFA content of the oil through the acid‐catalyzed stage, and yields in excess of 85% were achieved after the second stage of the reaction with a base catalyst. However, formation of water and soap prevented the separation of product phases. An alternative acid–base catalyzed scheme was examined which made use of a strong anion exchange resin to neutralize the substrate after the initial acid‐catalyzed stage. This scheme resulted in the effective removal of the acid catalyst as well as the residual FFA prior to the base‐catalyzed stage. The subsequent base‐catalyzed stage resulted in yields in excess of 98% for a 7.0 wt.% FFA corn oil and for the corn oil extracted from CDS.

Characterization of hybrid inorganic/organic polymer-type materials used for arsenic removal from drinking water

In the recent years, a new class of materials, inorganic/polymeric hybrid adsorbents, stands out as being very effective in removing trace concentrations of arsenic from contaminated groundwater. The inorganic component, hydrated ferric oxide (HFO) particles, very selective toward both As(III) and As(V) species, is irreversibly dispersed within a polymeric support using a chemical/thermal treatment. The hybrid adsorbents discussed in this paper use strong base anion (SBA) exchange resins of various porosities as polymeric host material. The efficiency of the hybrid adsorbent materials depends on three factors: the amount of adsorbent component (HFO), its dispersion and the accessibility to the adsorbent surface of HFO particles. The purpose of this study is the characterization of the hybrid products with emphasizes on the localization of HFO deposits in the porous structure of the polymeric supports, and how this localization influences the adsorption efficiency. Critical analysis of data obtained by conventional physical methods used for the characterization of porous solids (low temperature adsorption of nitrogen isotherms, mercury intrusion porosimetry, and scanning electronic microscopy (SEM)) reveals the layered HFO deposition on the pore walls, an essential condition for the most efficient adsorbents.