Resin Acids Research Articles

Pinoresinol stimulates keratinocyte proliferation and downregulates TNF-α secretion in peripheral blood mononuclear cells: An experimental in vitro study.

Natural coniferous resins are used in traditional medicine for the treatment of skin wounds. Coniferous wood resins ("callus" resin) are a mixture of abietic (resin) acids, lignans such as pinoresinol, and p-coumaric acid. The wound-healing properties of resins are thought to be related to their antimicrobial properties, but also to their effects on cell proliferation and inflammation. The purpose of this study was to identify and investigate the effects of novel aqueous dispersions of resin and its main components in the proliferation of human primary keratinocytes in vitroand in the expression of proinflammatory cytokines in human peripheral blood mononuclear cells. The proliferation studies were performed under low and high calcium conditions with or without added growth stimulators at the time points of 2and 6 days using AlamarBlue Cell Viability Reagent. The cytokine release assay was carried out by incubating the cells with the test articles for 18 h, after which the levels of tumor necrosis factor-α(TNF-α),interleukin-1β (IL-1β), IL-6, and IL-8 were measured in the supernatant by enzyme-linked immunosorbent assay. Resin and the purified lignan PINO, but not p-coumaric acid or abietic acid (industrial tall oil rosin), enhanced the proliferation of human keratinocytes in vitroand inhibited the expression of TNF-α, and to a lesser extent the expression of IL-1β in peripheral blood mononuclear cells. In this study, novel aqueous dispersions of spruce resin were used to investigate the effects of main resin components on keratinocyte proliferation and on the expression of key proinflammatory cytokines known to be associated with chronic wounds. The observations suggest that lignans, such as PINO, but not resin acids, are the components of resins that mediate the proliferative and TNF-α-suppressing effects. Lignans including PINO were identified as novel potential compounds in the treatment of chronic skin ulcers.

The role of acetonitrile in the direct synthesis of hydrogen peroxide over palladium supported by ion-exchange resins

Acetonitrile is used as an effective, non-corrosive selectivity enhancer for the direct synthesis of hydrogen peroxide (HP). Palladium catalysts supported by activated carbon or poly-divinylbenzene are poisoned by acetonitrile, which makes them very little productive. Conversely the catalysts supported by strongly acidic ion-exchange resin are much more selective and productive in the presence of acetonitrile, and for relatively long time. TEM shows that the size of their metal nanoparticles can be decreased by a reconstruction process, possibly sustained by leached palladium(II) species. HP decomposition experiments show that acetonitrile inhibits the OO bonds splitting.

A Greener Technique for Microwave-Assisted O-Silylation and Silyl Ether Deprotection of Uridine and Other Substrates

A single clean, good-yielding, environment-friendly microwave-assisted procedure for O-silylation of uridine with tert-butyldimethylsilyl chloride (TBDMSCl), 1,8-Diazabicyclo(5.4.0)undec-7-ene (DBU) and potassium nitrate as catalyst under solvent-free conditions is reported. Subsequent silyl ether deprotection is accomplished with a reusable acidic resin via microwave irradiation. Both the silylation and desilylation protocols have been applied to a panel of alcohols of pharmaceutical interest.

Resin Acids as Raw Material for the Preparation of Cyclodextrin Complexes Loaded with Dehydroabietitoic Acid and Chromenol Hybrid

In this work new methods to obtain complexes from β-cyclodextrin and dehydroabietic acid with chromenol-triazol hybrid with the sizes limits of approximately 0.1-250 μm are reported. Kneading, co-evaporation and co-precipitation for the resolution of racemic 2-tert-butyl-3-(1H-1,2,4-triazol-1-yl)-2H-chromen-2-ol for obtaining micro- and nanoparticles have been optimized. In vitro dissolution studies of the synthesized compounds in phosphate buffer (pH 6.8) showed an improved dissolution rate of chromenol-triazol hybrid in the inclusion complexes compared to the free form. The obtained β-complexes of β-cyclodextrin loaded with dehydroabietitoic acid and chromenol hybrid showed good antibacterial activity with MIC and MBC values ranging from 0.72 to 44.45 μM.

Esterification of 1-hexene and acetic acid using resin-supported phosphotungstic acid catalysts

As an atom economy technology, the direct esterification reaction of olefins plays a significant role in the production of organic esters. In this work, a series of resin-supported HPW catalysts were prepared using D101, D152, RM027, and A15 as the carriers, and they were used to prepare 1-methylpentyl acetate by the esterification of 1-hexene and acetic acid. The composition, structure, morphology, acid content, and other parameters of catalysts were characterized. In the esterification reaction, the activity order of catalysts is as follows: 20.0%HPW/A15 > 20.0%HPW/D101 > 20.0%HPW/D152 > 20.0%HPW/RM027. It depends on the acid strength of the carrier, the interaction between the carrier and HPW, and the HPW content. Moreover, it can be concluded that the weak acid resin carrier is completely inactive for the esterification reaction of 1-hexene, and the ratio of acetic acid to 1-hexene has a significant influence on the product selectivity. When n (acetic acid)/n (1-hexene) = 2, the optimum 1-methylpentyl acetate selectivity is 38.2%. Results of repeated experiments confirm that the stability of the active constituent is related to the type of functional groups on the carrier. Graphical Abstracts. 1-Methylpentyl acetate was successfully prepared by the direct esterification of 1-hexene and acetic acid using resin-supported HPW catalysts. The catalytic activity depends on the HPW content, the acid strength of the resin, and the interaction between HPW with the carrier, while the stability of the active constituent is related to the type of functional groups on the carriers.

Influence of rosin resin acids amides on the strength of interfiber bonds in paper in the z-direction

Resin acid amides of rosin, depending on the structure, can have both a hydrophobizing and hardening effect on paper pulps. It has been established that the developed products of rosin modification (adhesive rosin composition TMAS3N and polyamide resin ProChem DUO) containing amides of resin acids, when introduced into paper pulps made from fibrous suspensions of sulphate cellulose (unbleached and bleached) of coniferous and broad-leaved species and waste paper, different in the degree of grinding (25, 40 and 70 °ShR), contribute to the increase in the strength of interfiber bonds in paper in the z-direction. The effect of the TMAS-3N emulsion was compared with the traditionally used TM and AKD sizing emulsions. The introduction of the TMAS-3N emulsion into paper pulps (0.40 % of a. d. w.) provides the maximum increase in the strength of interfiber bonds in paper in the z-direction made from cellulose, equal to 16.7–88.6 %, and from waste paper – 19.4–75.4 %, which is 1.6–6.4 and 2.3–4.5 times more compared to TM emulsion, respectively. The achieved positive effect is due to the presence in the TMAS-3H emulsion of particles of the dispersed phase of hydroxyethylamides and aminoethyl ethers capable of forming hydrogen bonds with hydroxyl groups on the mating surfaces of cellulose fibers. Sizing paper stocks with AKD emulsion reduces the strength of interfiber bonds in paper in the z-direction over the entire range of paper content studied. Polyamide resin ProChem DUO, which is a polyaminoamide of rosin resin acids, at its content in paper stocks of 0.10 %, increases the strength of interfiber bonds in paper in the z-direction, made from cellulose and waste paper suspensions, by 50.0–92.3 and 44.4–63.5 %, respectively. The obtained results of increasing the strength of interfiber bonds in paper in the z-direction by resin acid amides of rosin are in full agreement with the mechanism of bridged bonds and the theory of hydrogen bonds.

Availability of extractives from various Norway spruce (Picea abies) stumps assortments

Stumps and knotwood of Norway spruce (Picea abies) are valuable sources of wood extractives. Although lignans from knotwood have already been utilized in value-added products, the behavior and valorization of stump-derived extractives are less studied. In this study, the composition of lipophilic and hydrophilic extractives, particularly lignans, from various spruce stump samples (stump bottom, stump heart, and crushed stump samples) stored outside were studied. Lipophilic and hydrophilic extracts were separated with an accelerated solvent extraction (ASE) apparatus using n-hexane and hot water, respectively. The detailed extractives content of samples was then determined by gas chromatography equipped with a flame ionization detector and a mass detector (GC-FID/MS) and high-performance liquid chromatography (HPLC). In stump bottom samples, an apparent decrease in total dissolved solids was observed in all the major extractives groups during storage: lignans, sugars, stilbene–glucosides, organic acids, resin acids, fatty acids, diterpenoids, and sterols. While a definitive decrease in extractives could not be demonstrated due to the moderately high variation of extractives among different samples, a good indication of the accessibility of important extractives in weathered stumps was obtained. Of the identified hydrophilic extractives, 79% were lignans, 53% of them being composed of 7-hydroxymatairesinol (HMR), 16% conidendric acid, and 12% todolactol. After 12 weeks of storage, the total amount of lignans was 15.3 mg/g of dry matter in stump bottom, 17.0 mg/g of dry matter in stump heart samples, and 10.2 mg/g of dry matter in crushed stump samples.

Microwave-assisted synthesis of alkyd resins using response surface methodology

Long alkyd resins for artistic applications were prepared by microwave synthesis of high-unsaturated vegetable oils. In this work, response surface method using split-plot optimal design was applied to optimize alkyd resin's acid value. Oil vegetable source (Sacha inchi and Linseed oil), temperature (200–240 °C), reaction time (4–12 min), and benzoic acid were evaluated as independent variables. Long alkyds resins with lower acid value considered optimal were characterized by FTIR and 1H-RMN techniques. Physicochemical properties, like color, viscosity, and drying time were assessed as well. Synthesis of alkyd resins from sacha inchi oil required less time and energy in comparison with linseed oil ones. Alkyd resins prepared with Sacha inchi oil for 210 °C and 12 min using 11.67 kJ/g at esterification stage provided a lower acid value (14 mgKOH/g), viscosity (W-X bubble Gardner), and Gardner scale color (11) in comparison with linseed oil.

Glycidyl Cinnamate: Copolymerization with Glycidyl Ethers, In‐Situ NMR Kinetics, and Photocrosslinking

AbstractThe copolymerization of glycidyl cinnamate (GC) as a hitherto non‐polymerizable, photoreactive epoxide structure to aliphatic polyether copolymers is described, using the monomer‐activated epoxide ring‐opening polymerization (MAROP). Ethoxyethyl glycidyl ether (EEGE) and GC are copolymerized employing triisobutylaluminum (i‐Bu3Al) as a catalyst and tetraoctylammonium bromide (NOctBr4) as an initiator. The amount of GC varies from 3 mol% to 100 mol%, which results in apparent molecular weights in the range of 2600 to 4600 g mol−1and dispersities (Đ)below 1.34. Studies of the microstructure by in‐situ1H NMR kinetics indicate a gradient‐like distribution of EEGE and GC (reactivity ratios:rEEGE= 0.28;rGC= 3.6), applying the ideal copolymerization model for evaluation. A tentative explanation relies on differing bond lengths in the respective epoxide rings, as suggested by density functional theory (DFT) calculations. Mild and selective cleavage of the acetal protecting groups of EEGE is achieved using the acidic ionic resin Dowex, leaving the GC ester bonds intact (Mn = 1900–3700 g mol−1,Đ <1.34). Thermal properties of the copolymers and the PGC homopolymer are investigated by differential scanning calorimetry (DSC). The crosslinking of P(G‐co‐GC) copolymers by UV irradiation allows hydrogel formation, which is confirmed by IR spectroscopy.

Theoretical and Experimental Insights of Benzimidazole Catalyzed by the Epoxy-Acrylic Acid Reaction.

This study focuses on the experimental and molecular-level investigation of epoxy acrylate formation. Epoxy acrylate vinyl ester resin was prepared by a reaction of diglycidyl ether of bisphenol-A-based epoxy resin and acrylic acid, using benzimidazole as a catalyst. It was confirmed that benzimidazole can effectively catalyze this reaction. FTIR analysis of the product revealed a simple addition esterification reaction between the epoxide group and carboxylic group of acrylic acid excluding the side reactions (e.g., etherification). DFT computational studies were performed to theoretically explore the insights of reaction mechanisms. The calculations revealed that the benzimidazole-catalyzed reaction dominates the uncatalyzed reaction. A comparison of calculated activation energies showed that concerted mechanisms are less significant in such reactions owing to their high activation barriers.

Optimization for Green Path in Wood Extractives by Taguchi Analysis

Extractive composition of Pinus pinaster (Maritime pine) wood was studied with choline chloride based deep eutectic solvents (DES). Two different eutectic mixtures (ChCl: Et-Gly; ChCl:Urea 1:2 molar ratio), two different extraction methods (hot water bath, ultrasound assisted extraction), and temperature (40 – 60 °C), time (30 – 60 min.) and solid:liquid ratio (1:10 – 1:20 g/mL) parameters were applied. For the optimization of operation conditions, Taguchi analysis was performed. Resin acids formed the chemical composition of Pinus pinaster (Maritime pine) wood. Dehydroabietic acid, abietic acid and isopimaric acid were found to be the major compounds. The impact of parameters on the performance of the system was determined as follows: DES type > solid:liquid ratio > extraction method > temperature > time. So, for the extraction of lipophilic compounds in Maritime pine wood, the optimum conditions were determined as hot water bath extraction at 60 °C with ethylene glycol and 1:10 solid liquid ratio for 60 min.

Chemical Composition and Biological Activity of Argentinian Propolis of Four Species of Stingless Bees.

The chemical composition of propolis of four species of stingless bees (SLBs) from Argentina was determined, and its antibacterial and anticancer activity was evaluated on selected types of microbes and cancer cell lines. Volatile secretions of all propolis samples are formed by 174 C2-C15 organic compounds, mainly mono- and sesquiterpenes and their derivatives. The chromatograms of ether extracts showed 287 peaks, of which 210 were identified. The most representative groups in the extracts of various propolis samples were diterpenoids (mainly resin acids), triterpenoids and phenolic compounds: long-chain alkenyl phenols, resorcinols and salicylates. The composition of both volatile and extractive compounds turned out to be species-specific; however, in both cases, the pairwise similarity of the propolis of Scaptotrigona postica and Tetragonisca fiebrigi versus that of Tetragona clavipes and Melipona quadrifasciata quadrifasciata was observed, which indicated the similarity of the preferences of the respective species when choosing plant sources of resin. The composition of the studied extracts completely lacked flavonoids and phenolcarboxylic acids, which are usually associated with the biological activity and medicinal properties of propolis. However, tests on selected microbial species and cancer cell lines showed such activity. All propolis samples tested against Paenibacillus larvae, two species of Bacillus and E. coli showed biofilm inhibition unrelated to the inhibition of bacterial growth, leading to a decrease in their pathogenicity. Testing the anticancer activity of ether extracts using five types of cell cultures showed that all four types of propolis studied inhibit the growth of cancer cells in a dose- and time-dependent manner. Propolis harvested by T. clavipes demonstrated the highest cytotoxicity on all tested cell lines.

L-Arginine as Bio-Based Curing Agent for Epoxy Resins: Temperature-Dependence of Mechanical Properties.

The precise characterization of new bio-based thermosets is imperative for the correct assessment of their potential as matrix material in fiber-reinforced polymer composites. Therefore, the mechanical properties of diglycidyl ether of bisphenol a (DGEBA) cured with l-arginine were investigated to determine whether the bio-based thermoset possesses the required mechanical properties for application as a matrix material. The cured thermoset is called Argopox. The mixture of amino acid and epoxy resin was prepared via three-roll milling and cured in the presence of an urea-based accelerator. The tensile, compression, flexural and toughness properties of Argopox were characterized at T=−40 ∘C, 22 ∘C and 80 ∘C to determine the temperature-dependence of the thermoset’s mechanical properties in its service temperature range. The glass transition temperature Tg was analyzed via dynamic mechanical analysis (DMA) and is approximately 119 ∘C. The tensile, compression and flexural strength at 22 ∘C are about 56 MPa, 98 MPa and 85 MPa, respectively. The critical stress intensity factor KIC and fracture energy GIC at 22 ∘C are roughly 1.1 MPam0.5 and 510 Jm−, respectively. Consequently, Argopox possesses mechanical properties that reach performance levels similar to that of materials which are already used as matrix for fiber reinforced composites.

The foliar trichomes of Combretum apiculatum subsp. apiculatum (Combretaceae): Morphoanatomy and histochemistry

Combretum apiculatum Sond. subsp. apiculatum is an important plant used in the traditional medicinal treatment of many diseases including gastrointestinal disorders, conjunctivitis, aches and leprosy. The plant's medicinal properties are putatively associated with secondary metabolites present in trichomes found on the leaf surfaces. This study aimed to investigate the distribution and morphology of the glandular trichomes of C. apiculatum at various stages of leaf development (emergent, young and mature) using stereo-, compound-light- and scanning electron microscopy, as well as to determine the leaf phytochemical constituents and to correlate the plant's medicinal properties at the cellular level by histochemical analyses. The microscopical studies revealed multicellular subsessile/sessile peltate, glandular trichomes and unicellular to multicellular non-glandular trichomes at all leaf developmental stages. Emergent leaves consisted of dense distributions of trichomes located in epidermal depressions, suggesting emergence during the early stages of leaf development. Trichome density decreased with leaf maturation, potentially attributable to the leaf expansion theory. Histochemical analyses on the leaves and trichomes detected alkaloids, phenolic compounds, lignin, terpenoids, resin acids, pectins, mucilage, carboxylated and hydroxylated polysaccharides, polyphenols, total lipids, total proteins and nucleic acids, indicating cell viability. These compounds possess medicinal properties, thereby providing supporting evidence for the plant's traditional medical use.

Improved performance of nafion membranes by blending ultra-high molecular weight polyvinylidene fluoride

Proton exchange membrane (PEM) is developing towards thin thickness and high mechanical strength for extraordinary performance proton exchange membrane fuel cells (PEMFCs). However, the commercial membrane such as Nafion can hardly satisfy the practical application of PEMFCs because of high gas crossover and low mechanical strength when the thickness is less than 20 μm. Here, a reinforced composite membrane (denoted as P110-PFSA) was synthesized by blending poly(vinylidene fluoride)(PVDF) featured with high molecular weight of Mw= 1100000 g mol-1 into perfluorosulfonic acid resin (PFSA). The P110-PFSA with the thickness of 15 μm exhibits tensile strength of over 33 MPa because the PVDF with high molecular weight forms a higher density of hydrogen bonds with PFSA, resulting in a reinforcement of the bonding strength between PVDF and PFSA. H2/O2 fuel cell performance with the P110-PFSA shows more than 1170 mW cm-2 fed with H2 at 70 °C and 100% RH much better than that with Nafion 211. Direct methanol fuel cell power densities of the blent PEM are 92, 61, 50, 28 and 15 mW cm-2 fed with 2, 6, 10,16 and 20 M methanol solution respectively at the anode.

Losartan Potassium and Verapamil Hydrochloride Compound Transdermal Drug Delivery System: Formulation and Characterization.

In this study, we developed a sustained-release transdermal delivery system containing losartan potassium (LP) and verapamil hydrochloride (VPH). LP and VPH have low bioavailability and long half-life. Therefore, the development of an optimum administration mode is necessary to overcome these drawbacks and enhance the antihypertensive effect. A transdermal diffusion meter was used to determine the optimal formulation of LP-VPH transdermal drug delivery systems (TDDS). Based on in vitro results, a sustained-release patch was prepared. Physical characteristics, including quality, stickiness, and appearance, were evaluated in vitro, while pharmacokinetics and skin irritation were evaluated in vivo. The results showed that 8.3% polyvinyl alcohol, 74.7% polyvinylpyrrolidone K30, 12% oleic acid-azone, and 5% polyacrylic acid resin II provided an optimized TDDS product for effective administration of LP and VPH. Furthermore, in vitro and in vivo release tests showed that the system continuously released LP and VPH for 24 h. The pharmacokinetic results indicated that although the maximum concentration was lower, both the area under the curve from 0-time and the mean residence time of the prepared patch were significantly higher than those of the oral preparations. Furthermore, the prepared LP-VPH transdermal patch showed good stability and no skin irritation. The developed LP-VPH TDDS showed a sustained-release effect and good characteristics and pharmacokinetics; therefore, it is an ideal formulation.

Preparation and Characteristics of Starch‐Based Pickering Emulsions: Effects of Rosin Acid and Starch Size

AbstractThis study aims to research the effects of rosin acid (RA) and size of starch on the properties of Pickering emulsifier. Potato (PS, 10–100 µm), corn (CS, 5–25 µm), and rice (RS, 3–8 µm) starches are modified with RA, and their starch ester is used to prepare Pickering emulsions. The results of scanning electron microscopy, X‐ray diffraction, and nuclear magnetic resonance hydrogen spectrum analysis reveal that the structure of native starch is largely destroyed, and esterification occurs between starch and RA. The starch‐based Pickering emulsion, which is esterified by RA, has the uniform particle size and higher stability than native starch. With prolonged storage, the emulsion of large‐sized RA–starch (PS and CS) show a stable gel phenomenon, and the emulsion of small‐sized RA–starch (RS) is a Newton fluid. In addition, the results indicate that RA–starch displays high viscosity and emulsifying properties.

Characterization of a Translucent Material Produced from Paulownia tomentosa Using Peracetic Acid Delignification and Resin Infiltration

Paulownia tomentosa, a tree species that allows for efficient production of translucent wood, was selected as an experimental wood species in this study, and a two-step process of delignification and polymer impregnation was performed. For delignification, 2–4 mm thick specimens were immersed in peracetic acid for 8 h. The delignified-wood specimens were impregnated using epoxy, a commercial transparent polymer. To identify the characteristics of the resulting translucent wood, the transmittance and haze of each type of wood section (cross- and tangential) were measured, while bending strength was measured using a universal testing machine. The translucent wood varied in properties according to the wood section, and the total transmittance and haze were 88.0% and 78.5% for the tangential section and 91.3% and 96.2% for the cross-section, respectively. For the bending strength, untreated wood showed values of approximately 4613.5 MPa modulus of elasticity (MOE), while the epoxy impregnation to improve the strength of the wood had increased the MOE up to approximately 6089.9 MPa, respectively. A comparative analysis was performed in this study with respect to the substitution of balsa, which is used widely in the production of translucent wood. The results are anticipated to serve as baseline data for the functionalization of translucent wood.

L-Arginine as a Bio-Based Curing Agent for Epoxy Resins: Glass Transition Temperature, Rheology and Latency

The need for sustainable practices in the processing chain of fiber-reinforced thermosets has led to the development of bio-based epoxy resins and curing agents. As a contribution to sustainable composites, this study focuses on the glass transition temperature (), viscosity and latency of diglycidyl ether of bisphenol a (DGEBA) cured with l-arginine in the presence of a urea-based accelerator. These characteristics are decisive features for application as a matrix in fiber-reinforced polymer composites produced via prepreg technology in which low viscosity and sufficient latency, meaning low reactivity of the one-component system, are necessary. The homogeneous mixture of amino acid and epoxy resin was prepared via three-roll milling. Two formulations, Argopox-1 with 1 accelerator and Argopox-2.5 with accelerator, were prepared and parts of each formulation were stored at 22 °C and −18 °C, respectively. Both formulations were tested via differential scanning calorimetry (DSC) and small amplitude oscillatory shear rheology (SAOS) after 0 d, 30 d, 60 d, 90 d and 180 d of storage to determine the influence of accelerator weight fraction, storage temperature and storage period on the glass transition temperature of the uncured resin system , and their viscosity. The of the thermosets is about 100 °C. The DSC and SAOS measurements show that the of Argopox-1 shifts about 5 °C in 60 d, while its viscosity is still low enough to be processed in a prepreg production line. Furthermore, Argopox-1 is storable for at least 180 d at −18 °C without significant changes in its and viscosity. Consequently, Argopox-1 possesses a sufficiently high and adequate latency, as well as a low viscosity for application as prepreg matrix material.

Recovery of rare earth elements from sulfate-rich acid mine water: Looking through the keyhole the exchange reaction for cationic resin

The ion exchange process for the recovery of rare earth elements (REE) from acid waters is investigated through combined experimental and theoretical approaches. Loading and elution experiments using a strongly acidic cation resin were carried out batchwise and in columns by applying laboratory solutions as well as crude acid mine drainage (AMD). Loading experiments, which assessed the competition of different species during the ion exchange process, showed the preference for La in detriment to Y. The resin was eluted with different inorganic acids and salts to remove the adsorbed REE. The best result was attained with the use of CaCl2 solution, having approximately 80 % of the REE eluted in the batch experiments. It was also noticed that as the flow rate decreased there was an increase in the elution from 80 % to 100 % for light REE and 50–90 % for heavy REE. DFT calculations indicated that the chemical models [LnSO4(H2O)7]+ and [Ln(SO4)2(H2O)5]- (LnLa, Y) are adequate to describe the chemical speciation. Furthermore, these species effectively interact with the resin sulfonic groups in a similar way as to the [Ln(H2O)9]3+ species, explaining why the loading results are high even in the presence of sulfate. For elution, the CaCl2 solution was modeled with the [Ca(H2O)6]2+ species, displacing the La and Y species from the resin. The estimated free energies involved in the mechanisms with and without SO42- are similar. Therefore, DFT calculations indicate that the functional group, which is present in the cation exchange resin, acts as a complexing agent.