Ion Exchange Resin Research Articles

Removal of Heavy Metals from Contaminated Aquatic Streams Using a Resin Supported Green nZVI

This study addresses the escalating demand for clean water resources driven by population growth and water quality deterioration. The research focuses on evaluating the efficacy of a nanocomposite material, incorporating zero valent iron nanoparticles into a chelating cation exchange resin matrix, for selectively removing heavy metals from polluted aquatic environments. The selected resin, featuring iminodiacetic acid functional groups, demonstrates notable selectivity for heavy metal cations over alkali earth metals. Column experiments were conducted to assess the nanocomposite’s performance, utilizing a feed solution spiked with heavy metals at concentrations ten times higher than Greek legislation limits for wastewater effluent recycling. The nanocomposite exhibited significant effectiveness for Cu, Cr(VI), and Pb, consistently maintaining Cu levels below detection limits and demonstrating limited breakthrough of Cr(VI) and Pb depending on experimental conditions. However, the removal efficiency was lower for Ni and insufficient for Cd, Zn, and As in this complex multicomponent solution. This research contributes valuable insights into the potential application of the developed nanocomposite for targeted removal of specific heavy metals in contaminated water sources, providing a foundation for further exploration and application in water remediation technologies.

Screening Peptide-Binding Partners for GenX via Phage Display.

Per- and poly-fluoroalkyl substances (PFAS), such as GenX, are a class of highly stable synthetic compounds that have recently become the focus of environmental remediation endeavors due to their toxicity. While considerable strides have been made in PFAS remediation, the diversity of these compounds, and the costs associated with approaches such as ion exchange resins and advanced oxidation technologies, remain challenging for widespread application. In addition, little is known about the potential binding and impacts of GenX on human proteins. To address these issues, we applied phage display and screened short peptides that bind specifically to GenX, with the ultimate goal of identifying human proteins that bind with GenX. In this study we identified the amino acids that contribute to the binding and measured the binding affinities of the two discovered peptides with NMR. A human protein, ankyrin-repeat-domain-containing protein 36B, with matching sequences of one of the peptides, was identified, and the binding positions were predicted by docking and molecular dynamics simulation. This study created a platform to screen peptides that bind with toxic chemical compounds, which ultimately helped us identify biologically relevant molecules that could be inhibited by the GenX, and also provided information that will contribute to future bioengineered GenX-binding device design.

Adsorbent Materials Used for the Treatment of Per‐ and Poly‐fluoroalkyl Substances (PFAS): A Short Review

AbstractPFAS, or per‐ and polyfluoroalkyl substances, have received considerable attention due to their persistence in the environment and potential health risks. To address this problem, adsorption has emerged as an effective method for removing PFAS compounds from water. This review provides a comprehensive analysis of various adsorbents used for PFAS removal, including activated carbon, ion exchange resins, clay, and emerging materials such as covalent and metal‐organic framework adsorbents. The effectiveness of these adsorbents in removing PFAS compounds is discussed, along with the factors influencing their adsorption, such as pH, competitive matters, and temperature.This article is protected by copyright. All rights reserved

Different mobile counter ion types of magnetic ion-exchange resin coupling with ozonation treatment of the organic matter, antibiotic resistance genes, and pathogens in secondary effluent

Advanced treatment and reuse of secondary effluents (SE) from wastewater treatment plants is considered an effective method of alleviating the conflict between water supply and demand. However, the effective removal of organic matter, antibiotic resistance genes (ARGs), and pathogens in SE is key to ensure the safety of reclaimed water. In this study, the effectiveness of three types of magnetic ion-exchange resins (R-X, where X refers to –OH, –HCO3, and -Cl) coupled with ozonation (R + O) in reducing different types of carbon, pathogens, intracellular and extracellular antibiotic resistance genes (iARGs and eARGs), and microbial communities in SE was investigated. The results indicated that R-Cl was the best pre-treatment resin for ozonation. R-Cl + O (8 mL/L R-Cl adsorption for 30 min, followed by 15 min of 8 mg/L ozonation) achieved removal efficiencies of 49.7 %, 86.6 %, 99.9 %, 87.1 %, and 99.9 % for dissolved organic carbon, UV254, ΣiARGs, ΣeARGs, and Σpathogens, respectively. Ozonation was more effective than resin adsorption in the removal of ARGs, and R-Cl + O had the lowest rebounding potential for iARGs and pathogens. In addition, R-OH had the lowest removal efficiency of organic matter, iARGs, and pathogens compared to other types of resins owing to the electrostatic repulsion mechanism. Molecular dynamics simulations and average reduced density gradient analysis revealed that the quaternary amine sites of the resin had a positive surface electrostatic potential, which could firmly adsorb double-stranded deoxyribonucleic acid by electrostatic action. Ozonation effectively reduced the risk of ARGs and pathogens in the effluent of resin. The R + O treatment reduced organic matter, ARGs, and pathogens more effectively than single treatment, despite the different anionic groups of the resin.

Dewatering Spent Ion-Exchange Resins with Supercritical CO2

ABSTRACT A process for dewatering spent ion exchange resins (gel and porous) used in nuclear power plants by supercritical CO2 (sCO2) is described. The amount of water removed by sCO2 is much higher than that expected from solubility considerations alone. Water from gel-type resins is both dissolved by and emulsified in sCO2. Emulsification also occurs in the absence of solids when water alone is contacted by sCO2. It is not a factor for microporous resins where an additional mechanism, viscous fingering, is involved. It appears that bulk water is emulsifiable but not if it is held in pores. Dewatering via viscous fingering has been previously invoked for matrices such as wood and sludge. The resins can be dewatered and dried with sequential batches of sCO2 at sub-boiling temperatures. The CO2 can then be potentially reused after expansion and separation from the entrained water. Partial decompression of the water-laden sCO2 would lead to cooling, which would drop the water solubility substantially. A reduction of temperature from 90 oC to 65oC reduces the solubility of water in sCO2 by a factor of five. The condensed water could then be separated with a hydrocyclone. The footprint of sCO2 is much smaller than the conventional drying process. The energy costs are also much lower because evaporation of water is avoided.

Desalting Plasma Protein Solutions by Membrane Capacitive Deionization.

Plasma protein therapies are used by millions of people across the globe to treat a litany of diseases and serious medical conditions. One challenge in the manufacture of plasma protein therapies is the removal of salt ions (e.g., sodium, phosphate, and chloride) from the protein solution. The conventional approach to remove salt ions is the use of diafiltration membranes (e.g., tangential flow filtration) and ion-exchange chromatography. However, the ion-exchange resins within the chromatographic column as well as filtration membranes are subject to fouling by the plasma protein. In this work, we investigate the membrane capacitive deionization (MCDI) as an alternative separation platform for removing ions from plasma protein solutions with negligible protein loss. MCDI has been previously deployed for brackish water desalination, nutrient recovery, mineral recovery, and removal of pollutants from water. However, this is the first time this technique has been applied for removing 28% of ions (sodium, chloride, and phosphate) from human serum albumin solutions with less than 3% protein loss from the process stream. Furthermore, the MCDI experiments utilized highly conductive poly(phenylene alkylene)-based ion exchange membranes (IEMs). These IEMs combined with ionomer-coated nylon meshes in the spacer channel ameliorate Ohmic resistances in MCDI improving the energy efficiency. Overall, we envision MCDI as an effective separation platform in biopharmaceutical manufacturing for deionizing plasma protein solutions and other pharmaceutical formulations without a loss of active pharmaceutical ingredients.

Ionic nanosphere as a novel sensitizer for luminescence from terbium(III) ion hybridized by facile ion-exchange process

Abstract Luminescence from terbium(III) species is typically weak due to its low absorption coefficient and slow radiative process despite its advantageous color purity. Hybridizing with a photosensitizer(s) is one of the most popular strategies to obtain intense luminescence from terbium(III) species. We have developed a novel photosensitizing system in which terbium(III) ion is hybridized with the ionic nanosphere, a class of spherical ion-exchange resins with a diameter of <300 nm. Terbium(III)-doped ionic nanospheres successfully exhibited obvious green luminescence upon the photoexcitation of the nanosphere at 260 nm. The terbium(III)–nanosphere hybrids can be prepared by a simple methodology, and sample conditions are controllable facilely.

ADSORPTION OF IRON(III) IONS FROM SULFURIC ACID SOLUTIONS BY DOWEX G-26 RESIN (Н)

The adsorption of iron (III) from sulfuric acid solutions on a strongly acidic cation-exchange resin Dowex G-26 (H) has been studied. The factors influencing the adsorption of iron (III) have been investigated: solution pH, contact duration, adsorbent dose, initial concentration of iron (III) in solution. The obtained results show that Dowex G-26 (H) resin has a high exchange capacity for iron (III) ions from sulfuric acid solutions. Complete adsorption of iron (III) was achieved at pH2 (99%). Based on the experimental results, Langmuir and Freindlich adsorption isotherms have been constructed. Both isotherms fully describe the adsorption of iron(III) by the Dowex G-26 adsorbent. However, a comparison of the Langmuir correlation coefficient (R2=0.9098) with respect to Freundlich (R2=0.9915) shows that the Freundlich isotherm provides a better fit than the Langmuir isotherm. Quantitative and quantitative sorption properties of Dowex G-26 (H) relative to iron (III) have been investigated using scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS). The maximum adsorption capacity (qm) for iron (III) was 166 mg/g at 250C. It has been shown that Dowex G-26(H) can be recommended as an adsorbent for sorption of Fe(III) from acidic solutions

Assessing Abuse-Deterrent formulations utilizing Ion-Exchange resin complexation processed via Twin-Screw granulation for improved safety and effectiveness

Opioid misuse is a public health crisis in the United States. In response, the FDA has approved drug products with abuse-deterrent features to reduce the risk of prescription opioid abuse. Abuse-deterrent formulations (ADFs) typically employ physical or chemical barriers or incorporate agonist–antagonist combinations as mechanisms to deter misuse. This study aims to assess the impact of abuse-deterrent properties, specifically ion-exchange resin complexation as a chemical barrier, on a model drug, promethazine hydrochloride (PMZ) tablets. Various formulations were developed through twin-screw wet granulation (TSWG) followed by twin-screw melt granulation (TSMG). In the TSWG process, the drug interacts with the resin through an exchange reaction, forming a drug-resin complex. Additionally, the study explored factors influencing the complex formation between the drug and resin, using the drug loading status as an indicator. DSC and ATR studies were carried out to confirm the formation of the drug-resin complex. Subsequently, hot melt granulation was employed to create a matrix tablet incorporating Kollidon® SR and Kollicoat® MAE 100P, thereby enabling sustained release properties. The drug-resin complex embedded in the matrix effectively deters abuse through methods like smoking, snorting, or parenteral injection, unless the drug can be extracted. In order to assess this, solvent extraction studies were conducted using an FDA-recommended solvents, determining the potential for abuse. Further investigations involved dissolution tests in change-over media, confirming the extended-release properties of the formulation. Results from dissolution studies comparing the ground and intact tablets provided positive evidence of the formulation's effectiveness in deterring abuse. Finally, alcohol-induced dose-dumping studies were conducted in compliance with FDA guidelines, concluding that the formulation successfully mitigates dose dumping in the presence of alcohol.

Sustainable approach for catalytic epoxidation of oleic acid followed by in situ ring-opening hydrolysis with applied ion exchange resin

Abstract Vegetable oils are rich in unsaturated bonds that can be converted to epoxidized oleic acid. They are considered sustainable, renewable, and also environmentally friendly. To date, there is a paucity of studies on production of dihydroxystearic acid (DHSA) using an eco-friendly ion exchange resin as it is not fully utilised. As a result, the aim of this study is to elucidate the mechanism of ring-opening by hydrolysis for the production of DHSA using amberlite IR-120H as a catalyst. The process of epoxidizing oleic acid involved the in situ generation of performic acid, which was then used to convert oleic acid into epoxidized oleic acid. This performic acid was created by combining formic acid, serving as the oxygen carrier, with hydrogen peroxide, acting as the oxygen donor. Under optimal conditions, the maximum relative conversion of oleic acid to oxirane was attained, with up to 85 %. Overall, DHSA with a high hydroxyl value (182 mg KOH/g), was successfully produced from oleic acid using in situ hydrolysis of epoxidized oleic acid.

Simple and efficient method for the extraction, isolation, and purification of peroxidase enzyme from wheat bran

AbstractPeroxidase is an industrially important enzyme with a broad range of applications. In this study, the extraction, isolation, and purification of peroxidase was conducted with wheat bran as a feedstock. Several commercially available buffers (K2HPO4, Na3PO4, CH3COONa, and Tris‐base) were explored for the extraction of peroxidase from wheat bran. Of the tested media, sodium acetate buffer gave an excellent performance and displayed maximum protein (0.44 mg mL−1) and enzyme activity (28 U mL−1). A process optimization study was also conducted to obtain the maximum protein concentration and enzyme activity. The intensified process provided 1.39 mg mL−1 protein concentration with 90 U mL−1 enzyme activity with specific enzyme activity of 135.8 U mg−1. Crude enzyme was purified using a three‐step process: (a) precipitation, (b) ultrafiltration, and (c) chromatographic purification. Commercially available strong and weak ion exchange resins, with different surface properties, were tested for purification. The weak anion exchange resin showed an excellent performance for maximum binding of peroxidase. Adsorption study investigated the best fit model of Freundlich isotherm with maximum binding capacity of 54 mg mL−1. Overall, purification provided peroxidase with a protein concentration of 1.24 mg mL−1 and 727.58 U mg −1 specific enzyme activity with purity increased by around ~6.6 fold. The reported process provides a simple and efficient method for the extraction and purification of peroxidase enzyme from wheat bran for its efficient valorization.

Shape-Selective Supramolecular Capsules for Actinide Precipitation and Separation.

Improving actinide separations is key to reducing barriers to medical and industrial actinide isotope production and to addressing the challenges associated with the reprocessing of spent nuclear fuel. Here, we report the first example of a supramolecular anion recognition process that can achieve this goal. We have designed a preorganized triamidoarene receptor that induces quantitative precipitation of the early actinides Th(IV), Np(IV), and Pu(IV) from industrially relevant conditions through the formation of self-assembled hydrogen-bonded capsules. Selectivity over the later An(III) elements is shown through modulation of the nitric acid concentration, and no precipitation of actinyl or transition-metal ions occurs. The Np, Pu, and Am precipitates were characterized structurally by single-crystal X-ray diffraction and reveal shape specificity of the internal hydrogen-bonding array for the encapsulated hexanitratometalates. This work complements ion-exchange resins for 5f-element separations and illustrates the significant potential of supramolecular separation methods that target anionic actinide species.

Purification of lipid oil using ion exchange resins

AbstractOil upgrading technologies for fuel production from second-generation feedstocks require pretreatments, such as the removal of ash metals in crude oil, to improve the catalytic performance in the process. The aim of this work was to purify lipid crude oil, derived from black soldier fly larvae (BSFL), from calcium by dry washing using ion exchange resins. Commercially available ion exchange resins suitable for organic liquids, namely GF 202 and Amberlyst 15DRY (AL 15), were selected for the purification experiments. The lipid material dissolved in nonanoic acid in different concentrations of mixtures was passed through a resin-filled plug-flow reactor at 50 °C and 75 °C with a liquid hourly space velocity (LHSV) of 4 h−1. The oil samples were analyzed for calcium using inductively coupled plasma-optical emission spectrometry, while the resin surfaces were examined by scanning electron microscopy. AL 15 showed a better overall performance and led to a case where over 99% of calcium was removed. Graphical abstract

Enhanced molten salt oxidation effect of nuclear grade cation exchange resin in lithium containing catalytic salt system

The Cation ion-exchange resins (CERs) can be effectively oxidized in molten Li2CO3-Na2CO3-K2CO3, but the high price of Li2CO3 requires further clarification of its necessity in the molten salt oxidation (MSO) process of CERs. In this paper, Li+ ions are introduced into CERs by ion exchange, and the direct oxidation of pure CERs and Li+ doped CERs and the MSO process of Li+ doped CERs in Na2CO3-K2CO3 (Li+ in CERs), pure CERs in Li2CO3-Na2CO3-K2CO3 (Li+ in molten salt) and pure CERs in Na2CO3-K2CO3 (without Li+) were compared. Thermo-gravimetric analyzer (TGA) and gas mass spectrometry data illustrate that the introduction of Li+ can increase the peak content of CO2 and SO2 and reduce the mass of residue. Fourier transform infrared spectroscopy (FT-IR) results reflect that the presence of Li+ can advance the temperature of resin skeleton destruction. Scanning electron microscope (SEM) displays the fracture degree of CERs is more severe in Li2CO3-Na2CO3-K2CO3 than other two systems. X-ray diffraction spectrum (XRD) and the content of carbonate and sulfate are used to analyze the composition of waste salt after MSO. Compared with other two systems, the content of sulfate produced by adsorption of SO2 and residual carbonate are the highest in Li2CO3-Na2CO3-K2CO3. Thermodynamic calculation using HSC chemistry 6.0 evidences that in Li2CO3-Na2CO3-K2CO3, Li2O produced by decomposition of Li2CO3 can provide oxygen ions, while Na2CO3 and K2CO3 can absorb SO2. Changing the oxidation temperature and oxidation time in different systems, the destruction and removal efficiency (DRE) of CERs are comprised. The DRE of Li+ in molten salt can achieve 99.99 % of CERs at a lower oxidation temperature and less oxidation time than other salt systems. In summary, the superiority of Li2CO3 in ternary salts is difficult to replace at present.

Removal of Ca(II) and Mg(II) ions from solutions to sulfonic cation exchanger based on plasticized polyvinylchloride

The ion-exchange material was obtained by oxidation of the product of the interaction of polyvinyl chloride with an aqueous solution of calcium polysulfide. The structure of the resulting cation exchanger and metal-containing hybrid material was identified by IR spectroscopy and elemental analysis. The kinetics of absorption of metal ions in cation exchange resin was analyzed by using pseudo-first and pseudo-second order models. The rate constants in the adsorption process were calculated. According to the correlation coefficient, it was determined that the sorption process proceeds according to the laws of a pseudo-second order reaction. Based on the equilibrium sorption it was evaluated according to the isotherm models of Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich (D-R). The results showed that the absorption of Ca2+ and Mg2+ ions from aqueous solutions in cation exchange resin displays the best accordance with the Langmuir monomolecular theory. In addition, the results showed that the cation exchanger (PVC-SO3H) effectively cleans river water from Ca2+ and Mg2+ ions for industrial enterprises.

Effects of Addition of Lanthanum and Zinc Oxides on the Biological Properties of TiO2-SiO2-P2O5/CaO on Ion Exchange Resin for Bone Implantation.

The spherical materials TiO2-SiO2-P2O5/CaO, TiO2-SiO2-P2O5/La2O3, and TiO2-SiO2-P2O5/ZnO deposited on the Tokem-250 cation exchanger have been synthesized with an alcoholic solution by the sol-gel method. The macroporous cation exchanger Tokem-250, which has high Ca2+, Zn2+, and La3+ ion selectivity, was used in the present study. This material has the ability to precipitate and mineralize calcium phosphates on its surface in biological media, since it has high porosity, a homogeneous structure with a uniform variation of elements, and the presence of active centers (Si4+, Ti4+) on the surface. The effect of lanthanum and zinc additives on biological properties has been studied. It was established that accumulation of Ca2+ and Mg2+ occurs faster on the surface of TiO2-SiO2-P2O5/ZnO in the SBF (simulated body fluid) model solution, showing higher reaction capacity. The amount of calcium and phosphorus ions on the surface of sample TiO2-SiO2-P2O5/La2O3 is greater due to the ability of lanthanum to coordinate a large number of ions (lanthanum coordination number is 10). The presence of zinc ions in the system causes the partial hemoglobin release from erythrocytes into the supernatant fluid. The samples with lanthanum ions reduce the amount of protein in plasma after incubation, which has a positive effect on the practical application.

Heavy metal decontamination by ion exchange polymers for water purification: counterintuitive cation removal by an anion exchange polymer

Ion exchange polymers were used for mercury and lead ions removal in water. The heavy metal ion concentration was analyzed by two independent methods: inductively coupled plasma–optical emission spectroscopy (ICP-OES) and gravimetry. The studied cation exchange polymer (CEP) was sulfonated poly(ether ether ketone) (SPEEK), and the anion exchange polymer (AEP) was poly(sulfone trimethylammonium) chloride (PSU-TMA). The removal capacity was connected with the ion exchange capacity (IEC) equal to 1.6 meq/g for both polymers. The concentration ranges were 0.15–0.006 mM for Hg2+ and 10.8–1.0 mM for Pb2+. SPEEK achieved 100% removal efficiency for mercury and lead if the concentration was below the maximum sorption capacity (Qmax), which was about 210 mg/g for Pb2+ with SPEEK. For PSU-TMA, the surprising removal efficiency of 100% for Hg2+, which seemed incompatible with ion exchange, was related to the formation of very stable complex anions that can be sorbed by an AEP. Langmuir adsorption theory was applied for the thermodynamic description of lead removal by SPEEK. A second-order law was effective to describe the kinetics of the process.

Parameter estimation for reactive chromatography model by Bayesian inference and parallel sequential Monte Carlo

Reactive chromatography overcomes many disadvantages of conventional separation processes by improving yields and reduces costs by combining reaction and separation in a single operation. Model-based optimization is essential to realize industrial applications of this process. Parameters in the model must be estimated accurately, and evaluating the uncertainty of the model parameters is crucial. However, uncertainty quantification of model parameters has not been performed for reactive chromatography processes. In this study, we propose an approach to estimate the parameter uncertainty of reactive chromatography processes using Bayesian inference and parallel sequential Monte Carlo. As an example, the esterification synthesis of acetic acid and methanol catalyzed by a cation exchange resin was considered. Parameter estimation was performed using a reactive chromatography experiment and a non-reactive experiment in which only the products were injected. The results of the analysis showed that using both the reactive and non-reactive chromatography experimental data simultaneously improved the accuracy of the estimation. In addition, correlations between some parameters were revealed.

Green chemistry route to chitosan hydrogels and investigation of the materials as efficient dye adsorbents

Abstract Biopolymer-based materials for the adsorption of toxic dyes represent an interesting class of materials for environmental applications. Here we report on chitosan as the starting material for synthesizing dye adsorbents. In particular, the synthesis, characterization, and cationic dye adsorption properties of chitosan hydrogel adsorbents are reported. Polyanionic itaconated chitosan derivatives were synthesized in solvent-less conditions for the first time. Itaconated chitosan was cross-linked using thiol-ene chemistry to obtain hydrogels. The influence of the incorporated carboxylate groups and the cross-linker fraction on the adsorption of Methylene Blue (MB) was investigated. In addition, the impact of pH, adsorbent dose, initial concentration, and ionic strength were investigated to determine the optimum conditions for MB uptake, and the dye uptake kinetics, adsorption isotherms, selectivity, and reusability of the adsorbents were unveiled. A maximum adsorption capacity of 556 mg/g could be achieved, outperforming commercial activated charcoal and ion exchange resins. Furthermore the chitosan hydrogel adsorbents were shown to capture >90 % of cationic MB from a binary equimolar mixture with the anionic dye Methyl Orange. Since the adsorbents can be regenerated and re-used afterwards at least 20 times, retaining a high dye adsorption fraction of >95 %, these materials are promising candidates for environmental applications.

Commercial turpentine oil enriched with α-terpineol using an acid heterogeneous catalyst

The hydration of α-pinene, limonene, β-pinene, and commercial turpentine oil in the presence of strong acidic cation exchange resin Amberlyst-15 was studied. The acid catalytic hydration was performed in a batch reactor, and the effect of solvent at various temperatures and reaction times was evaluated. The main hydration product obtained from α-pinene was α-terpineol with a yield of 36 % (4 h, 70 °C, 2-propanol as solvent); however, the selected catalytic system was even more active to obtain α-terpineol when β-pinene was used as a substrate, obtaining α-terpineol yield of 38 % in 2 h of reaction. For the hydration of turpentine (70 °C, turpentine:water:2-propanol mass ratio of 1:0.5:2, 15 % w/w catalyst) the composition of reaction mixture after 4 h was 35 % w/w of α-terpineol, 8 % w/w of α-pinene, and 0.5 % w/w of β –pinene, which correspond to a final content of α-terpineol similar to the concentration obtained when α-pinene was used as a substrate (36 % w/w).