Amberlite XAD-2 Research Articles

A novel solvent-impregnated resin containing 3-hydroxy-2-naphthoic acid for stepwise extraction of Th(IV) and U(VI) over other coexistence ions

ABSTRACTA new solvent-impregnated resin (SIR) was constructed using Amberlite XAD-2 and 3-hydroxy-2-naphthoic acid (3H2NA). The SIR was applied for stepwise extraction of Th(IV) and U(VI) from the coexistence ions dissolved in aqueous media at pHs of 3.0 and 7.0, respectively. The U(VI) and Th(IV) ions adsorbed on the minicolumn were consecutively eluted with 0.5 M and 4 M HCl solutions. They were then measured by Arsenazo III at their maximum absorption wavelengths. The characteristic parameters for the successful separation of these ions from the aqueous media were investigated. The SIR showed excellent reproducibility during the 800 subsequent extraction cycles.

Influence of the textural characteristics of the support on Au(III) sorption from HCl solutions using Cyphos IL101-impregnated Amberlite resins

A series of Amberlite XAD resins (acrylic ester and styrene–divinylbenzene resins) has been impregnated with Cyphos IL101 ionic liquid (IL: trihexyl(tetradecyl)phosphonium chloride) for Au(III) sorption from HCl solution. The textural characteristics (specific surface area, pore size distribution and pore volume) of the extractant impregnated resins (EIRs) have been determined in function of IL loading. The HCl concentration and the IL loading have a significant impact on Au(III) sorption efficiency: acrylic ester resins can weakly bind Au(III) contrary to styrene–divinylbenzene resins that only extract metal ions through the ion exchange of tetrachloro-anionic species with chloride ions from the IL. Uptake kinetics are strongly controlled by both the IL loading, the textural properties of the resin and, in some cases, by the pre-conditioning of the resin. Though a clear correlation exists between pore size/pore volume and apparent intraparticle diffusion coefficients, some resins showed atypical behavior (having lower relative coefficients of intraparticle diffusion than expected from the textural properties of raw resins, while their De fits better the actual textural properties of impregnated materials). Sorption efficiency increases with IL loading while uptake kinetics is slowed down. A good compromise is obtained in terms of both sorption efficiency and uptake kinetics using XAD-1180 resin impregnated with Cyphos IL101 (with IL loading not exceeding 400mgILg−1EIR).

Application of modified simplex on the development of a preconcentration system for cadmium determination in sediments, food and cigarettes.

A modified simplex algorithm was used to optimize a system of preconcentration for cadmium determination in samples of sediments, cigarettes and food using flame atomic absorption spectrometry. The preconcentration system is based on the sorption of cadmium in a minicolumn packed with Amberlite XAD-2 resin functionalized with 3,4-dihydroxybenzoic acid (DHB). The optimized variables were pH and sampling flow rate and the optimum conditions found for these variables were, respectively 8.7 and 8.8 mL min-1. The developed system showed a preconcentration factor of 15.3, detection limit of 0.49 µg L-1, quantification limit of 1.65 µg L-1 and precision expressed as relative standard deviation (% RSD, n=10) of 5.9. The accuracy of the method was checked by analysis of estuary sediment certified reference material (NIST 1646-1). The cadmium concentrations found in sediment samples ranged from 1.73 and 1.90 µg g-1. In cigarette samples the results were 0.085 and 0.193 µg g-1, and in food samples (coriander and lettuce) the concentrations found of this metal were, respectively, 0.33 and 0.12 µg g-1.

Extraction and Purification of Phenolic Compounds from Lignocellulosic Biomass Assisted by Ionic Liquid, Polymeric Resins, and Supercritical CO2

A sustainable process of valorization of lignocellulosic biomass exploring the extraction and separation of high value phenolic compounds was developed. A scale-up pretreatment and fractionation process of biomass assisted by 1-ethyl-3-methylimidazolium acetate ([emim][OAc]) ionic liquid (IL) was carried out at first. Thereafter, recovered IL formed a sample rich in phenolic compounds, which separation and purification was the main objective of the present work. The phenolic extraction from the recycled IL was studied employing adsorption methodology with specific polymeric resins. Amberlite XAD-7 and Silica C18 resins showed the highest extraction efficiency of phenolic compounds, while PVPP presented high selectivity toward tricin and a specific lignin fragment. Among the examined resins, Amberlite XAD-7 demonstrated the highest ratio of phenolic compounds extraction in comparison to IL. A residual quantity of IL was observed to remain in the extracted samples and this was overcome by applying supercrit...

Sorption of the herbicides diquat and difenzoquat from aqueous medium by polymeric resins in the presence of sodium dodecylsulfate: Kinetic and mechanistic study

ABSTRACTThe goal of this work was to propose a novel method for the solid-phase extraction of the herbicides diquat (DQT2+) and difenzoquat (DFQT+) from aqueous medium using polymeric Amberlite XAD-2 and XAD-4 resins in the presence of sodium dodecylsulfate (SDS). The addition of SDS to the medium was of fundamental importance in order to allow the formation of a negatively charged surface able to sorb the cationic solutes. Several factors that could influence the sorption process, such as SDS concentration in the medium, sorbent mass, pH, ionic strength, and initial concentration of the solutes were investigated. Kinetic studies were also performed to model the system and to identify the mechanisms that operate the sorption process of the herbicides. SDS concentration in the medium presented remarkable influence on the extraction efficiency, achieving maximum values when the ratios [SDS]/[herbicide] were approximately 90, for XAD-2, and 22 and 11 for DQT2+ and DFQT+, respectively, for XAD-4. The sorption process followed a pseudo second-order kinetic in all cases studied. It was also found that an intraparticle diffusion process controlled exclusively the sorption of the herbicides by the Amberlite XAD-2 and XAD-4 resins in the first 15 min, becoming less active with time.

Equilibrium and Kinetic studies on Pb2 +, Cd2 +, Cu2 + and Ni2 + Adsorption from aqueous solution by Resin 2, 2'– (Ethylenedithio)diethanol Immobilized Amberlite XAD-16 (EDTDE-AXAD-16) with Chlorosulphonic acid

The present study aims to investigate the adsorption behavior of Pb2+, Cd2+, Cu2+ and Ni2+ ions from aqueous solution onto modified Amberlite XAD-16 functionalized using 2, 2'– (Ethylenedithio) diethanol with chlorosulphonic acid. The batch equilibrium method was used for studying the metal sorption. It has been observed that the Pb(II) ion is highly adsorbed compared to other metal ions and the adsorption capacity was found to be in the sequence Pb2+ >Cd2+ >Ni2+>Cu2+and the preference of this sorbent for a metal may be explained on the basis of electronegativity of the metal ions and on the basis of hard - soft Lewis acids and bases concept. Adsorption kinetics was explained based on pseudo-first-order and pseudo-second order models. The data showed that the sorption of metal (II) ions on the chelating resin perfectly fit a pseudo-second-order model.

Extraction of humic substances from fresh waters on solid-phase cartridges and their study by Fourier transform ion cyclotron resonance mass spectrometry

Humic substances (HS) have been extracted from fresh waters on macroporous adsorbents of different types, Amberlite XAD-8 resin and Bond Elute PPL solid-phase cartridge. Comparative analysis of the extracted samples by ultra-high resolution mass spectrometry demonstrated selectivity of the selected adsorbents to the components of the molecular assembly of HS: the XAD-8 resin has affinity to the higher oxidized aromatic compounds and PPL has affinity to substances of stronger aliphatic character and nitrogen-containing compounds. Because of this fact, a comparison of the molecular composition of HS isolated from various sources must be performed taking into account selective adsorption; therefore, it is necessary to compare the products extracted by the same adsorbent for correct interpretation.

Solid-phase extraction of explosive nitramines on macroreticular polymers modified by freezing with water or acetone.

A novel approach is proposed to modify the porous structure and surface properties of the polymers used in solid-phase extraction. The approach involves soaking in water or acetone, followed by freezing in liquid nitrogen (77.4 K) and was employed for two polymeric materials: Amberlite XAD-7 and Amberlite XAD-16. Variations in the surface properties of the adsorbents were justified by the action of acetone and water as solvents affecting the textural and other characteristic of the materials. The initial and treated adsorbents were used in extraction of explosive nitramines from aqueous samples. The performed modifications of the polymer texture allow us to increase the recovery rate as compared with the initial adsorbents. The results were justified by the swelling of fragments of the polymers and by the additional process of sorption of nitramines. The results indicate that polymeric adsorbents can be easily modified by the soaking/freezing process and the materials can be achieved that prove usefulness for the effective separation of explosive nitramines from aqueous samples.

Assessment of monoamide extractants and solid supports as new extraction chromatographic materials

Abstract The potential of monoamide-based extraction chromatographic materials for actinide recovery was assessed by monitoring uranium partitioning into six different materials. These materials were comprised of two solid supports (Amberlite XAD 4 and XAD 7) coated with one of three extractants: di-2-ethylhexyl butyramide (DEHBA), di-2-ethyhexyl isobutryamide (DEHiBA), or di-2-ethyhexyl acetylamide (DEHAA). This report considers differences in uranium partitioning depending on the solid support, extractant, aqueous phase conditions and amount of extractant coating on a given support. Studies indicate the acetyl amide extractant coated onto XAD 7 is a top candidate for further investigation. This is an interesting finding as the acetyl amide is not generally considered a particularly useful extractant for solvent extraction separations due to its tendency to form a third phase. This information contrasts the general paradigm that a given extractant can be equally useful for extraction chromatographic or solvent extraction separations and indicates that the development of future classes of extraction chromatographic materials should carefully consider the role of alkyl groups in their optimization. Additionally, the efficacy of the developed monoamide materials are compared with more classically utilized organophosphorous materials to consider opportunities for advancement in f-element separations.

A mass transfer model for the fixed-bed adsorption of ferulic acid onto a polymeric resin: axial dispersion and intraparticle diffusion

ABSTRACTIn this study, amberlite XAD-16 (XAD-16) bed column system was used to remove ferulic acid (FA) from aqueous solutions. Laboratory-scale column experiments were conducted in downflow fixed bed at initial FA concentration of 1 g/L, initial pH 3, and 25°C. The performance of the adsorbent bed under different flow rates (1.3–7.7 mL/min) was studied. The bed utilization efficiency was in the range of 64.64–72.21% at the studied flow rates. A mass transfer model considering both axial dispersion and intraparticle diffusion was developed to predict the breakthrough curves of FA adsorption on XAD-16. This model predicted the experimental data better than Bohart–Adams model and Thomas model, based on the low deviation between predicted and experimental data. The axial dispersion coefficient value varied from 6.45 × 10−6 to 1.10 × 10−6 m2/s at flow rate from 1.3 to 7.7 mL/min, whereas the intraparticle diffusion coefficient was 1.04 × 10−10 m2/s, being this last resistance the rate-limiting step. In conclusion, axial dispersion and intraparticle diffusion phenomena play the major role in predicting the adsorption of FA onto XAD-16 in fixed-bed columns.

Sorption of ruthenium by dipropylmethyl-2-(N,N-diisobutyl) acetamidoammonium iodide impregnated Amberlite XAD-4 resin from nitric acid medium

ABSTRACTDipropylmethyl-2-(N,N-diisobutyl)acetamidoammonium iodide has been impregnated on Amberlite XAD-4 resin and investigated for sorption of Ru from nitric acid medium. Equilibrium sorption data for Ru uptake were represented well by the Langmuir isotherm equation (R2 = 0.98) compared to Freundlich isotherm equation (R2 = 0.86). The maximum monolayer coverage (Q0) value of 6.25 mg/g as obtained from Langmuir isotherm was close to the experimental value (5.63 mg/g). The heterogeneity parameter (1/n) = 0.37 obtained from the slope of Freundlich isotherm indicates slight heterogeneity in sorption process. Aqueous solutions of 5% ammonia or 10% sodium hydroxide were found suitable for desorption. The method can be applied for separation of Ru from acidic waste solutions.

Selective Electroanalytical Method for the Determination of Roxarsone in Poultry Feed and Litter

An extremely sensitive and selective voltammetric method was developed for the determination of roxarsone (ROX) at a newly modified carbon paste microelectrode in Britton–Robinson buffer (BRB) at pH 2.0. The electrode is based on a disposable plastic pipette tip filled with carbon paste based on a mixture of graphite powder and Amberlite XAD-4 (5:1, w/w). The experimental parameters, such as pH, type of the buffer, mode of voltammetry, accumulation potential, accumulation time, and stirring rate were optimized. The reduction peak current dependences were linear for the concentration of ROX from 2.0 to 100 μM. The method showed reproducible results with RSD (n = 11) of <2.0 %. The limit of detection (LOD) and limit of quantification (LOQ) were 0.53 and 1.76 μM, respectively. ROX showed that there was no apparent surface passivation indicating the suitability of the modified electrode for ROX detection. The developed method was successfully applied for the determination of ROX in poultry feed and poultry litter collected from various localities of Hyderabad.

Analysis of Some Trace Metals in Fish Species after Preconcentration with Congo Red on Amberlite XAD-7 Resin by Flame Atomic Absorption Spectrometry

A new procedure for separation and preconcentration of trace amounts of Cu(II), Ni(II), Fe(III), Zn(II), Cr(III), Cd(II), and Pb(II) in fish samples was proposed. The procedure is based on the adsorption of these metal ions on the column of Amberlite XAD-7 as congo red complexes prior to their determination by flame atomic absorption spectrometry (FAAS). Several factors that can affect the sorption and elution efficiency of the metal ions were investigated and optimized. The sorption was quantitative in the pH range of 6.0–9.0 for Cu(II) and Ni(II), 5.5–8.0 for Fe(III), 6.0–8.5 for Zn(II) and Cd(II), and 7.0–8.5 for Cr(III) and Pb(II). The optimum pH for simultaneous retention was 7.5. The sorption capacity of the resin was found to be 0.89, 0.72, 0.82, 0.61, 0.53, 0.84, and 0.78 mg/g for Cu(II), Ni(II), Fe(III), Zn(II), Cr(III), Cd(II), and Pb(II), respectively. The precision of the method was evaluated as the relative standard deviation obtained by analyzing a series of six replicates and below 6% for all seven elements. The validation of the method was performed by the analysis of certified reference materials. The proposed method was successfully applied to separation/preconcentration and determination of these metals in fish samples.

Comparative study for the separation, preconcentration, and determination of copper and cadmium in real samples by using two different ligands

Two new solid phase extraction methods have been developed for simultaneous separation and preconcentration of Cu(II) and Cd(II) in some food and environmental samples before their determination by flame atomic absorption spectrometry (FAAS). One of these methods is based on the absorption of the Cu(II) and Cd(II) complexes with [3-(cyanomethyl)-5-(4-methylphenyl)-4$H$-1,2,4-triazol-4-yl]carbamate (L1) and the other is based on the absorption of the Cu(II) and Cd(II) complexes with 4-(4-methylphenyl)-5-{[pyridine-4-yl-4$H$-1,2,4-triazole-3-yl)thio]methyl}-4$H$-1,2,4-triazole-3-thiol (L2) on Amberlite XAD-1180 resin. The metal complexes are retained on resin at pH 6.0 and eluted with 1.0 mol L$^{-1}$ HCl in acetone in both methods. After the optimum conditions were determined, the methods were applied to seawater, stream water, rice, lentil, tea, tobacco, bulgur, chickpea, wheat, red pepper, black pepper, peppermint, and dried eggplant samples in order to determine the levels of copper and cadmium.

A Fast and Simple Voltammetric Method Using a Lead Film Electrode for Determination of Ultra-Trace Concentration of Titanium in Environmental Water Samples

A fast, simple and highly sensitive adsorptive stripping voltammetric procedure for determination of trace quantity of Ti(IV) in natural water samples containing high concentrations of surfactants and humic substances was developed. The procedure was based on simultaneous lead film formation and adsorptive accumulation of the Ti(IV)-cupferron complex onto the in situ plated lead film electrode. Measurement conditions such as the concentration of cupferron, pH of the supporting electrolyte, conditions of lead film formation, accumulation potential and time were optimized. The interferences from dissolved surfactants and biosurfactant were eliminated by adding Amberlite XAD-7 resin to the voltammetric cell. Under optimum conditions the linear calibration plot for Ti(IV) was obtained in the range from 5.0 × 10−9 mol L−1 to 1.5 × 10−7 mol L−1 for the accumulation time of 60 s. The detection limit for the accumulation time of 60 s was about 1.7 × 10−9 mol L−1. The calibration graph obeyed the equation y = 0.487x + 0.843, where y and x were the peak current (μA) and Ti(IV) concentration (nmol L−1), respectively. The linear correlation coefficient was r = 0.996. The proposed method was successfully applied to determine titanium in the matrix-rich water sample and was validated in the course of Ti(IV) recovery determination from spiked natural water samples.

Extraction of Honey Polyphenols: Method Development and Evidence of Cis Isomerization.

Honey polyphenols have been studied with the objective of relating honeys to their floral sources. Initially synthesized by plant, these polyphenols can be found in the plant’s nectar, which are collected by bees, which convert the nectar into honey. Consequently, polyphenols constitute minor components of honey. The development of a solid-phase extraction method for honey polyphenols is presented in this study. The technique employs Amberlite XAD-2 adsorbent and was tested on monofloral honeys from six different plants: acacia, chestnut, eucalyptus, thyme, sunflower, and wild carrot. Analyses were performed using high-performance liquid chromatography coupled with UV detection and mass spectrometry. Several phenolic acids and flavonoids were identified: caffeic and p-coumaric acids, quercetin, kaempferol, naringenin, chrysin, and pinocembrin. Generally, the quantity of a given polyphenol in the honey was around 0.2 mg/100 g of honey, except for chestnut honey, which contained around 3.0 mg of p-coumaric acid/100 g of honey. Analyses highlighted significant formation of cis isomers for phenolic acids during the extraction despite protection from light.

Efficiency of Polyphenol Extraction from Artificial Honey Using C18 Cartridges and Amberlite® XAD-2 Resin: A Comparative Study

A comparative study of the extraction efficiency of nine known polyphenols [phenolic acids (benzoic acid, dihydroxybenzoic acid, gallic acid, trans-cinnamic acid, and vanillic acid) and flavonoids (naringenin, naringin, quercetin, and rutin)] was conducted by deliberately adding the polyphenols to an artificial honey solution and performing solid phase extraction (SPE). Two SPE methods were compared: one using Amberlite XAD-2 resin and another one using a C18 cartridge. A gradient high performance liquid chromatography system with an RP18 column and photodiode array detector was utilized to analyze the extracted polyphenols. The mean percent of recovery from the C18 cartridges was 74.2%, while that from the Amberlite XAD-2 resin was 43.7%. The recoveries of vanillic acid, naringin, and rutin were excellent (&gt;90%); however, gallic acid was not obtained when C18 cartridges were used. Additionally, the reusability of Amberlite XAD-2 resin was investigated, revealing that the mean recovery of polyphenols decreased from 43.7% (1st extraction) to 29.3% (3rd extraction). It was concluded that although Amberlite XAD-2 resin yielded a higher number of compounds, C18 cartridges gave a better extraction recovery. The lower recovery seen for the Amberlite XAD-2 resin also cannot be compensated by repeated extractions due to the gradual decrease of extraction recovery when reused.

Adsorption of bisphenol A from aqueous solutions by Pleurotus eryngii immobilized on Amberlite XAD-4 using as a new adsorbent

The adsorption of bisphenol A (BPA) in a fixed-bed column was evaluated in this work. Fungus Pleurotus eryngii isolated from Tunceli (Turkey) immobilized on XAD-4 resin was used as an adsorbent for decontamination of BPA from aqueous solutions. The extent of BPA removal capacity was evaluated as a function of parameters such as pH, volume of the sample, and column bed height. Adsorption isotherms of BPA on immobilized P. eryngii were determined and correlated with common isotherm equations such as Langmuir and Freundlich models. The mechanism of adsorption of BPA was analyzed preadsorption (XAD-4 + fungus) and postadsorption (XAD-4 + fungus + BPA) using fourier transform infrared spectroscopy. The results show that adsorption ability of BPA by immobilized P. eryngii is possible and this system yields the best degree of BPA removal (90%) at pH 11 for an initial load of 120 mg L−1. Therefore, this material can be used as a very effective adsorbent for BPA decontamination in aqueous solutions.

Evaluation of salinity effect on quantitative analysis of aquatic humic substances using nonionic DAX-8 resin.

A nonionic macroporous resin, Amberlite(®) XAD-8, or its substitute, Supelite™ DAX-8, is used when isolating or quantifying aquatic humic substances (AHS). However, the effect of salinity on the adsorption behavior of AHS onto the resin is yet to be confirmed, rendering the possibility of salinity-induced changes in the values of quantified amounts or characteristics of AHS obtained from a salty system. To verify the results of quantification and isolation of AHS using the resin in different salinity systems, the effect of salinity on such quantitative analyses of AHS has been examined. It has been concluded that the salinity effect is in general trivial and will not hinder comparison of results regardless of sample solution salinity.

Solid phase extraction of Cu (II), Ni (II), Co (II), and Fe (III) ions in water samples using salicylaldehyde benzoylhydrazone on Amberlite XAD-4 and their determinations by flame atomic absorption spectrometry

A multi element preconcentration procedure for solid phase extraction on Amberlite XAD-4 as their salicylaldehyde benzoylhydrazone chelates and flame atomic absorption spectrometric determination of some trace metal ions in water samples are proposed in this work. The influences of some analytical parameters, including pH of aqueous solution, amounts of reagent, flow rates of sample and eluent solutions, and sample volume on the quantitative recoveries of copper, nickel, cobalt, and iron were investigated. The effects of concomitant ions on the retentions of the analytes were also examined. The developed method has been successfully applied to the determination of metal ions in some real samples, including, tap water, river water, spring water, and waste water.