Sulfonated Cation Exchange Research Articles

Fouling evaluation of polyethersulfone (PES)/sulfonated cation exchange resin (SCER) membrane for BSA separation

ABSTRACTIn this study, antifouling membranes were prepared through dry wet‐phase inversion method. The incorporation of electrostatistically charged group of sulfonate cation exchange resins (SCER) into polyethersulfone membrane matrix attempts to give a synergistic combination of properties for bovine serum albumin (BSA) removal. The effect of different composition of SCER into the blend membranes were characterized using scanning electron microscopy, atomic force microscopy, porosimeter, attenuated total reflectance Fourier transform infrared spectroscopy, and goniometer. All the prepared membranes were evaluated for BSA separation. The membrane resistance of all membranes decreases with increase in SCER loading. Among all membranes, P3 membrane shows a better fouling, reversible and irreversible resistance for BSA, signifying that the attached BSA on the membrane surface can be easily removed by physical cleaning. The improvement in hydrophilicity of P3 membrane was found to be the dominant factor in mitigating BSA fouling. The results demonstrated that BSA fouling could be alleviated by varying SCER concentration in the polyethersulfone matrix. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45854.

Isolation of Peptides from Calf Brain Tissue and Evaluation of their Tissue-Specific and Stimulatory Activity

A method for separating a mixture of calf brain peptides by extraction with aqueous HOAc followed by fractionation of the extract by cross-flow (tangential) microfiltration and solid-phase extraction was developed. The isolated peptide mixture contained constituents with molecular masses within 0.1 – 3 kDa. Low-pressure ion-exchange chromatography of this mixture over Dowex 50WX8 sulfonated cation exchanger isolated a pure peptide consisting of the five amino acids Arg, Lys, Gly, Ser, and Leu. The biological activity of the obtained pentapeptide was estimated on organotypic brain slice culture explants of Wistar rats. It was established that the peptide possessed high tissue-specific and stimulatory activity for brain explants that was greater than those of the commercial preparations Cortexin and Cerebrolysin.

Efficient Catalytic Upgrading of Levulinic Acid into Alkyl Levulinates by Resin-Supported Acids and Flow Reactors

Biomass-derived levulinic acid (LA) is an excellent substrate to obtain high-value esters that can be used as second-generation biofuels and biofuel additives. The present study focuses on the identification and definition of the key parameters crucial for the development of chemically and environmentally efficient protocols operating in continuous-flow for the preparation of structurally diverse alkyl levulinates via the esterification of LA. We have focused on the use of solid acid catalysts consisting of sulfonated cation exchange resins and considered different aliphatic alcohols to prepare levulinates 3 and 11–17 regioselectively, and in good to high yields (50–92%). Direct correlations between several reaction parameters and catalyst activity have been investigated and discussed to set proper flow reactors that allow minimal waste production during the workup procedure, enabling Environmental factor (E-factor) values as low as ca. 0.3, full recoverability and reusability of the catalysts, and the production of levulinates up to ca. 5 gxh−1 scale.

Mechanism and sorption parameters of alkali metal ions on strongly acidic cation exchange resins

The kinetic performance of strongly acidic sulfonate cation exchange resins towards ions of alkali metals (Li, K, and Na) under static conditions has been examined. Kinetic parameters of the sorption process, in particular, half-time of exchange and maximum possible flow rate of solution through the sorption column in the dynamic mode have been determined. The sorption kinetics mechanism has been explored. Recovery of the elements from model unicomponent solutions on strongly acidic cation exchange resins is satisfactorily described by pseudo-second-order kinetic model.

Evaluation and application of a targeted SPE-LC-MS method for quantifying plant hormones and phenolics in Arabidopsis.

Application of metabolomics techniques to plant physiology is now considerable, and LC-MS is often being used for non-targeted, semi-quantitative analysis of effects caused by mutations or environmental conditions. However, examination of signalling metabolites like hormones require absolute rather than semi-quantitative quantitation, since their effect in planta is strongly dependent upon concentration. Further, plant hormones belong to different chemical classes and thus simultaneous quantitation remains highly challenging. Here we present an LC-MS method that allows the simultaneous absolute quantitation of six hormone families as well as selected phenolics. The technique requires solid phase extraction with a sulfonated cation exchange phase before analysis, and use calibration curves instead of isotopically labelled standards, which are indeed not commercially available for many hormonal molecules. The use of the total signal (including adducts) rather than a single quantifying mass appears to be crucial to avoid quantification errors because the ion distribution between adducts is found to be concentration-dependent. The different hormones considered appear to have contrasted ionisation efficiency due to their physical properties. However, the relatively low variability and the satisfactory response to standard additions show that the technique is accurate and reproducible. It is applied to Arabidopsis plants subjected to water stress, using either the wild-type or lines with altered NAD biosynthesis causing changes in salicylate signalling and phenylpropanoid levels. As expected, analyses show an increase in abscisic acid upon water stress and a consistent modification of phenolic compounds (including salicylate) in mutants.

Ozonolysis of isoquinoline in a polystyrene-based sulfonate cation exchanger

Nanoreactor ozonolysis of aromatic heterocycles is studied. It is found that cinchomeronic acid (which is used in the production of medical preparations) may be obtained by the nanoreactor ozonolysis of isoquinoline, which is a component of the heavy pyridine bases obtained in the distillation of coal tar.

Polyethylene-graft-sulfonated polystyrene membranes for the separation of ethylene–ethane mixtures

Sulfonated cation exchange membranes have been prepared by the postradiation graft polymerization of styrene on a 20-μm-thick low-density polyethylene film and the subsequent sulfonation of the grafted polystyrene. The distribution of sulfonated polystyrene in the membranes at varying degree of grafting has been described using IR spectroscopy data. It has been shown that the permeability of the membranes to ethane and ethylene decreases with the increasing degree of grafting. The use of gas mixtures with a low ethylene content leads to the suppression of the ethane permeability coefficient and an increase in the separation factor. The highest separation factor of 57 has been achieved at the 140% degree of grafting of the polymer from a mixture containing 5% ethylene.

Furfural based policondensation type sulfonic acid cation-exchange resin

Furfural based policondensation type sulfonic acid cation-exchange resin

Role of simple anionic ligands in deep decontamination of liquid radioactive waste

The influence of the NO9-, SO42–, HCO3–, and Ac– anions on the efficiency of the sorption of bivalent metals by sulfonic cation exchangers was studied. The main method was elution of the Mg2+, Ca2+, and Co2+ cations with individual solutions of the corresponding sodium salts and their mixed solutions with sodium nitrate from the Dowex-50 ion-exchange resin at fixed temperatures. The exchange efficiency is influenced both by neutral complexes of the metal cations mainly with inorganic acid ligands and by the single-charged species. The latter species affect the efficiency of the ion-exchange waste reprocessing considerably more strongly. An increase in the temperature of the solution being treated leads to a significant shift of the peak position toward larger retention volumes, which indicates that it is appropriate to perform the water treatment on sulfonic cation exchangers at elevated temperatures. The first formation constant of the single-charged cobalt dihydrogen phosphate complex species at an ionic strength of 0 M was obtained: logK1(CoH2PO4+) = 1.36.

Determining role of hydrogen bonding in electrically driven membrane transport: Quantum-chemical and molecular dynamics study

By quantum chemistry and molecular dynamics analysis of the structure and chemical bond energy of the hydrated ion pair in a sulfonated cation exchange membrane, hydrogen bonding has been shown to play the determining role in electrically driven membrane transport in systems of this kind. The characteristics of hydrogen bridges linking hydrate water molecules in the sulfonated cation exchange membrane have been studied using the molecular dynamics method.

Esterification of Pentanoic Acid with 1-Propanol by Sulfonated Cation Exchange Resin: Experimental and Kinetic Studies

Liquid-phase esterification reaction of 1-propanol with pentanoic acid to give propyl pentanoate over Amberlyst 15 has been studied. The reaction carried out in a batch reactor was found to be independent of mass transfer effects in the temperature range of 323.15–363.15 K. The reaction is highly temperature sensitive. Increase in 1-propanol concentration has an enhancing effect on the conversion, whereas water acts as an inhibitor. As alcohol–acid mixtures behave nonideally, kinetic analysis has been performed using UNIFAC liquid-phase activities of pentanoic acid, 1-propanol, propyl ester, and water. Observed kinetics is best represented by Eley–Rideal mechanism. Surface reaction was observed to be a rate-limiting step.

The Colon as the Potassium Target: Entering the Colonic Age of Hyperkalemia Treatment?

The Colon as the Potassium Target: Entering the Colonic Age of Hyperkalemia Treatment?

Stabilization of copper nanoparticles with volume- and surface-distribution inside ion-exchange matrices

Nanocomposites characterized by the surface and volume distributions of deposited copper nanoparticles are obtained via the chemical deposition of copper onto sulfonic acid and carboxylic cation exchanger and strongly basic anion exchanger matrices. The electrode behavior of the synthesized composites in CuSO4 solution is studied by open-circuit chronopotentiometry. The effect the nature of the fixed centers of the ion-exchange matrix has on the initial state of metallic particles and the processes that occur in solutions of their metal ions is established from the deviation of the nanocomposites’ electrode potential from the potential of a compact electrode and the nature of its change over time. It is shown that the mechanism behind the interaction of the matrix and metal ions (ion exchange, non-exchange absorption, complexation) determines not only the initial size and distribution of metal particles, but also the rate at which they achieve aggregative stability.

Kinetic and thermodynamic studies of the esterification of acidified oil catalyzed by sulfonated cation exchange resin

This study describes the kinetics and thermodynamics of the esterification of acidified oil with methanol catalyzed by sulfonated cation exchange resins (SCER). The effects of the mass ratio of methanol to acidified oil, reaction temperature, and catalyst loading were studied to optimize the conditions for maximum conversion of free fatty acids (FFAs). The results showed that the optimal conversion rate of FFAs was 91.87% at the mass ratio of methanol to acidified oil of 2.5:1.0, reaction temperature of 65.0 °C, catalyst loading of 5.0 g and reaction time of 8.0 h. The external and internal mass transfer resistances were negligible based on the experimental results and a pseudo-homogeneous kinetic model was proposed for the esterification. The activation energy and thermodynamic parameters including ∆G, ∆S and ∆H were determined. The conversion rates of FFAs obtained from the established model were in good agreement with the experimental data.

Evaluation of ferromagnetic hybrid polymers obtained using cation exchangers

Ferromagnetic hybrid polymers containing iron oxide deposit were obtained using sulfonic and carboxylic cation exchangers. The influence of ion exchange capacity, chemical constitution and porous structure of the polymeric matrix on the form and the quantity of iron oxide deposit was studied. Obtained materials contained the iron oxide load amounting to 9.0–23.0% Fe. The XRD, and IR and Mössbauer spectroscopic studies showed that hybrid polymers obtained using sulfonic cation exchangers contained mainly maghemite and magnetite within the polymeric matrix, while the inorganic deposit incorporated within the matrix of caboxylic cation exchangers was the mixture of iron oxide polymorphs (magnetite, maghemite, lepidocrocite, green rust and also Fe(OH)2). Due to high content of magnetite and maghemite deposited within the polymer matrix of the macroporous sulfonic cation exchanger this product showed highest magnetization saturation amounting 26 emu/g.

Optimization of acidified oil esterification catalyzed by sulfonated cation exchange resin using response surface methodology

The esterification of acidified oil with ethanol catalyzed by sulfonated cation exchange resins (SCER) was optimized using the response surface methodology (RSM). The effects of the molar ratio of ethanol to acidified oil, reaction time and catalyst loading on the conversion rate of free fatty acids (FFAs) were investigated at the temperature of the boiling point of ethanol. Results showed that the highest conversion rate of 75.24% was obtained at the molar ratio of ethanol to acidified oil of 23.2, reaction time of 8.0h and catalyst loading of 35.0wt.%. Moreover, the conversion rate of FFAs was increased to 98.32% by using a water adsorption apparatus under the RSM optimized conditions. Scanning electronic microscopic–energy dispersive spectrometric (SEM–EDS), X-ray diffractometric (XRD) and thermogravimetric–derivative thermogravimetric (TG–DTG) analyses confirmed that the morphology of catalysts did not change much and the mechanical and thermal stabilities were still good after the reaction. Furthermore, SCER exhibited a high catalytic activity and stability after being reused for five successive times. The fuel properties of the biodiesel were comparable to that of ASTM, EN and GB biodiesel standard.

Computer simulation of the structure of a sulfonated cation exchanger in the form of valinium salt

Quantum chemical and molecular dynamics simulation of a fragment of a sulfonated cation exchanger in the form of valinium salt has been performed. Contact ionic pair formation has been found.

Redox polymer with N,N‐dichlorosulfonamide functional groups as arsenite oxidant in aqueous solutions

ABSTRACTA macroporous, styrene‐divinylbenzene polymer with N,N‐dichlorosulfonamide functional groups (SO2NCl2), containing two chlorine atoms with oxidation number +1, have been prepared through the chemical modification of a commercial sulfonic cation exchanger (Amberlyst 15, Rohm and Haas). Obtained product was used as the heterogeneous oxidant of As(III) in aqueous solutions. The polymer's oxidizing capacity, determined as part of the batch studies, amounted to 193.29 mg As(III) g−1 (pH = 7.7) and 206.03 mg As(III) g−1 (pH = 2.0). The suitability of the redox polymer for long‐lasting operation in the aqueous environment was confirmed in the column study conducted using a solution with a concentration of 10 mg As(III) dm−3 at a flow rate of 6 bed volumes (BV) h−1. The concentration of As(III) in the effluent reached the value of 0.01 mg As(III) dm−3 only after 8 weeks of continuous operation when 7930 BV of the solution had passed through the bed. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41552.

Electroreduction of oxygen on metal (Au, Cu)-ion exchanger nanocomposites in the diffusion mode

The kinetics of the electroreduction of oxygen in the diffusion mode on single granules of nanocomposites consisting of dispersed particles of the metal (Au, Cu) of the nanometer size and macroporous sulfonic cation-exchanger matrix KU-23 is studied. No noticeable effect of the factors of size of the metal component and ion exchange over the matrix on the external diffusion current of oxygen reduction is observed. The drop in current observed in a number of cases is due to a transition to the mixed external and internal kinetics as a result of the macroporous structure of the matrix and the chemical activity of nanoparticles of the metal component.

Energy efficient continuous production of γ-valerolactone by bifunctional metal/acid catalysis in one pot

A bifunctional heterogeneous catalyst based on sulfonated cation exchange resin and embedded Ru nanoparticles shows complete conversion and selectivity at low temperatures and H2 pressure in the direct, one-pot conversion of levulinic acid to GVL under continuous flow conditions, with excellent durability and no need for additives.