Sulfonic Cation-exchange Resin Research Articles

Separation of Phenylalanine Aqueous Salt Solutions by Electrodialysis Using Membranes with Different Mass Fractions of Sulfonated Cation-Exchange Resin

Separation of Phenylalanine Aqueous Salt Solutions by Electrodialysis Using Membranes with Different Mass Fractions of Sulfonated Cation-Exchange Resin

TITANOMAGNETITE CONCENTRATE PROCESSING BY SORPTION CONVERSION

A hydrometallurgical technology for processing titanomagnetite concentrate has been proposed and justified. It includes the decomposition of the concentrate in low-concentration sulfur-acidic solution in the presence of sulfonic cation exchanger in H+ form with the transfer of the main part of the metals of the titanomagnetite concentrate into the sorbent and obtaining a residue enriched with ilmenite, desorption of metals from the saturated sulfonic cation exchanger with a 5 M sodium chloride solution, fractional hydrolytic precipitation and separation of titanium hydroxide, vanadium-enriched iron hydroxide, pure hydroxide iron and mixtures of iron and manganese hydroxides, regeneration of sulfonic cation exchange resin. The optimal parameters for carrying out individual processes have been determined. The technology practically does not consume sulfuric acid and does not generate liquid waste.

Development and study of adsorption properties of a new sulfur polyvinyl chloride cation exchanger for water treatment

The article analyses the sorption properties of thermally and chemically stable sulfonic cation exchange resin based on PVC. The article presents the temperature dependence of the analysis results of the sorption properties of Ca2+ and Mg2+ ions of sulfonated PVC. The results of the obtained sorption analysis are scientifically confirmed in the article. In addition, spatial Bode angle diagrams are presented, which provide very important scientific evidence of single maxima at intermediate frequencies. Purification of industrial waste water of enterprises was carried out with the help of the obtained sulfonic cation exchanger.

A new polishing method for complex structural parts: Moist particle electrolyte electrochemical mechanical polishing (MPE-ECMP)

The improvement of the surface quality of complex structural parts is a major challenge. Electrochemical mechanical polishing (ECMP) plays an important role in the polishing of wafers due to its high material removal rate. However, electrochemical mechanical polishing of the surface of complex structures, such as the bevels of turbine blades, has been little investigated. This paper proposes a new method, moist particle electrolyte electrochemical mechanical polishing (MPE-ECMP), for polishing the surfaces of complex structural parts. Using a sulfonated cation exchange resin as a moist particle electrolyte (MPE), polarization curves are measured using linear scanning voltammetry (LSV) and a selected potential of 1.0 V vs. Hg|Hg2SO4 over a 1 h polishing period. The elemental changes on the copper surface are examined by energy dispersive spectroscopy (EDS) and those on the MPE surface are studied using X-ray photoelectron spectrometry (XPS) to explain the material removal mechanism. The results show that the surface roughness of copper is reduced from the initial Sa = 433.48 nm to Sa = 21.83 nm, a reduction of 95.0%, that no copper oxides are generated during the MPE-ECMP process and that the MPE adsorbs released Cu2+. It is demonstrated that MPE-ECMP has good surface finishing properties for beveled surfaces, and provides an effective approach for surface polishing of complex structural parts.

Sorption of pyridine-3-carboxylic acid by the Dowex-50 sulfonic cation-exchange resin in the NiII and CuII forms

Sorption of pyridine-3-carboxylic acid by the Dowex-50 sulfonic cation-exchange resin in the NiII and CuII forms

Ion Exchange Treatment of Cobalt Acetate Solutions to Remove Iron(III) Impurity

The possibility of removing an iron(III) impurity from cobalt acetate solutions by sorption was examined. Among a number of tested ion exchange resins with various functional groups (Purolite С150 sulfonic cation exchange resin, Purolite А500 strongly basic anion exchange resin, complexing ion exchange resins Purolite S930 with iminodiacetate and Purolite S950 with aminomethylenephosphonic acid groups, Purolite S957 cation exchange resin containing phosphonic and sulfonic acid groups simultaneously), only the ion exchange resins containing phosphonic acid groups, namely, Purolite S950 amphoteric resin and Purolite S957 cation exchange resin, are capable of the iron(III) sorption, with the latter resin showing considerably higher performance. The iron(III) distribution coefficients in sorption on these resins reach a maximum at рН 3.8–5.1. When passed through a column packed with Purolite S957 cation exchange resin, cobalt acetate solutions containing 40.6 and 57.2 g L–1 Co and 21 and 24 mg L–1 Fe undergo deep iron removal to its residual concentration no higher than 1.0–1.5 mg L–1. The sorbed iron(III) is virtually completely eluted from the cation exchange resin with 9 column volumes of 1.5 М sulfuric acid containing 10 g L–1 ascorbic acid after the resin pretreatment with an ascorbic acid solution.

Сорбционное извлечение редкоземельных элементов на сульфокатионите КУ-2-8 из азотнокислых растворов вскрытия лопаритового концентрата

The experimental-industrial study results of the process of sorption of rare-earth elements on sulfonic cation-exchange resin KU-2-8 from nitrate solutions of loparite concentrate development are presented. Values of different obtained elements are discussed. Different changes in processes are described. Reprocessing loparine raw materials in the close cycle without hydrochloric and sulfuric acid, and excess of normative sodium content in productional concentrate is possible. Keywords: ionite, sorption, loparite concentrate, rare-earth element, thorium.

Sorption of pyridine-3-carboxylic acid and silver(I) from multicomponent aqueous solutions with Dowex-50 sulfonic cation exchange resin

The equilibrium distribution of pyridine-3-carboxylic acid, silver(I) ions, and protons between aqueous solutions and Dowex-50 sulfonic cation exchange resin was studied. The counter-ion composition of the cation exchange resin was determined by solving a system of equations for binary ion exchange selectivity coefficients and the mass balance equation. According to FT IR and CPMAS 13C NMR spectroscopy of solid samples, pyridine-3-carboxylic acid exists in the Dowex-50 phase as [H2L]+ cations. High distribution constants indicate that pyridine-3-carboxylic acid and silver can be concentrated in the polymer phase.

Decomposition of an Eudialyte Concentrate with Nitric Acid by Sorption Conversion

The nitric acid decomposition of an eudialyte concentrate by sorption conversion is studied. This method is based on the interaction of the concentrate with a low concentrated solution of HNO3 in the presence of sulfonic cation-exchange resin. During sorption conversion, the target metals are predominantly sorbed by a sorbent, which is easily separated from the solution and silica gel-containing residues. When the solution containing 2% HNO3 is used, the extraction of rare elements is comparable and the acid consumption is 6–8 times lower than that in the case of the traditional decomposition of an eudialyte concentrate using concentrated nitric acid. The procedure simultaneously produces a nonradioactive silica gel product appropriate for the production of qualitative building materials. The possibility of the further increase in the degree of extraction of rare elements is discussed. A route for the processing of the sorbent saturated with rare metals is proposed to produces salt concentrates of these elements.

Separation of curium and americium from spent fuel reprocessing solutions via displacement complexing chromatography on sulfocationites

The process of curium and americium separation from solutions after spent fuel reprocessing by displacement complexing chromatography on sulfonic cation exchange resins was reported. Separation runs were performed using a 2-stage chromatographic process sequence. Stage 1 constituted the primary purification and produced the enriched trans-plutonium elements (TPE) concentrate by means of removing the principal quantity of light rare earth elements, namely, La, Ce, Nd, and Pr. Deep refining of the TPE concentrate from the residual chemical and radiochemical impurities was performed at Stage 2. The paper reports the results of three experimental cycles of americium and curium separation. The best results were obtained in Cycle 3, where the key factor was the application of the monodispersed Tokem-308 cationite. The purity of curium in the fraction containing 50% of the feed curium-244 was 99% relative to americium. About 60% of the enriched americium-241,243 fraction contained < 0.1% of Eu-154,155 by radioactivity and < 0.8% of Cm-244 by mass.

Furfural Dipropyl Acetal as a New Fuel Additive: Synthesis and Properties

Liquid-phase acetalization of 1-propanol with furfural was studied. A procedure was recommended for preparing furfural dipropyl acetal on a sulfonic cation-exchange resin. The possibility of repeated use of the catalyst without significant loss of the activity was demonstrated. An experimental sample was synthesized, isolated, purified, and characterized. Its specific heat of combustion, density, refractive index, induction period in the mixture, and antiknock and lubricating properties were determined. Furfural acetals show promise as a fuel additive.

Catalytic Condensation of Carbonyl Compounds during the Synthesis of Cyclohexanone in the Production of Caprolactam

Kinetic features of the condensation processes of carbonyl and unsaturated impurities in cyclohexanone have been studied using model mixtures in a heterophase system in the presence and absence of phase-transfer catalysts. It has been shown that linear aldehydes are condensed with cyclohexanone in the heterophase system in the presence and absence of phase-transfer catalysts under mild conditions (30–50°C). Noncarbonyl unsaturated compounds (e.g., 2-cyclohexene-1-ol) can be removed only at temperatures above 100°C in the presence of acidic catalysts (e.g., high-temperature sulfonated cation-exchange resins). Unsaturated cyclic ketones are characterized by both alkylation reactions over acid catalysts and aldol condensation reactions in the presence of an alkali, thereby suggesting the possibility of their elimination at different cyclohexanone purification steps. The theoretical models built can be used to develop an effective cyclohexanone purification technology that will substantially enhance the manufacturability of high-purity caprolactam and polyamide.

Sorption rerecovery and concentration of rare-earth metals from extraction phosphoric acid. Review

The review covers the methods for sorption recovery and concentration of rare-earth metals (REM) from solutions of extraction phosphoric acid (EPA). Sorption extraction of the REM seems most appropriate at the stage of primary concentration, but a significant amount of iron (III) and calcium as the most interfering impurities are the problem, both at the stage of sorption and at the stage of desorption. The results of studies on the sorption of trivalent ions of cerium, lanthanum and iron on sulfonic cation-exchange resin KU-2-8 and macroporous weakly acidic cation exchange Cybber CRX 300, are presented. It is established that the cation exchanger Cybber CRX 300 by exchange capacity for lanthanum and cerium and kinetic properties is inferior somewhat to sulfonic cation-exchange resin KU-2-8 at sorption from acidic solutions, but can be used to concentrate and separate the REM from iron. The review presents data of the pilot trials of the technology for extracting rare-earth metals from dihydrate extraction phosphoric acid (45 % P2O5) produced by «PhosAgro-Cherepovets» JSC (RU). The results of tests of sorbents TP260, Purolite S957 (Monophos), sulfonic cation-exchange resin РРС 160 and sorbent АА03 at sorption: from sulphate solution after decomposition of phosphate raw materials; from a solution of hydrolysis sulfuric acid after precipitation of titanium dioxide; from sulfuric acid solutions after sorption of uranium are presented. The distribution of rare-earth metals during their sorption by KU-2 sulfonic cation-exchange resin from solutions of phosphoric acid, as follows: dihydrate EPA partially evaporated 43.69 wt. % P2O5, «Balakovo Mineral Fertilizers» JSC; dihydrate EPA, without evaporation 26.09 wt. % P2O5, OJSC «Ammofos»; dihydrate EPA, evaporated 52.54 wt. % P2O5, «Ammofos» OJSC, was studied. The distribution coefficients of individual lanthanides are obtained. The analysis of literature data has shown that the choice of sorbent is the most difficult task when developing the technology for sorption extraction of REM from multicomponent solutions.

Complex Radiochemical Analysis of Natural Waters and Nuclear Power Plant Wastewaters. Specific Features of the Method for Radiochemical Determination of 90Sr

A procedure was developed for complex analysis of γ-emitting nuclides and 90Sr in natural and wastewaters with two methods of preparation of counting samples for 90Sr activity measurement: coprecipitation of 90Sr with strontium sulfate and coprecipitation of 90Y with yttrium hydroxide. Strontium-90 is concentrated on KU-2-8chs strongly acidic sulfonic cation-exchange resin in the Н+ form after removing γ-emitting radionuclides on complex selective sorbents, which are simultaneously counting samples for measuring the activity of γ-emitting nuclides. The main steps of the sorption procedure for the complex analysis are described, and the choice of the method for preparing a counting sample based on 90Y for current radioecological monitoring is substantiated.

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.

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.

Furfural based policondensation type sulfonic acid cation-exchange resin

Furfural based policondensation type sulfonic acid cation-exchange resin

The role of para–meta isomerization in the selective synthesis of para-tert-butylphenol in the presence of modern macroporous sulfonic cation-exchange resins

The formation of meta-tert-butylphenol (m-TBP), which decreasing the quality of the commercial product, is shown to be possible in the target synthesis of para-tert-butylphenol (p-TBP) in the presence of sulfonic cation-exchange resins using macroporous Amberlyst 36 Dry as an example. The equilibrium concentration of m-TBP in the liquid phase (the maximum value at 409 K is 47 wt %) is calculated from experimental and published data. Up to 10 wt % m-TBP (on the reaction mixture basis) is formed at the maximum values of temperature (409 K) and contact time (450 min). Kinetic characteristics are determined for the \(p - TBP + phenol\underset{{{k_{ - 6}}}}{\overset{{{k_6}}}{\longleftrightarrow}}m - TBP\) + phenol reaction, which supplements the kinetic model for the production of p-TBP. The rate constants of this reaction are several orders of magnitude smaller than those for the main (ortho–para) transformations. The temperature range (353–383 K) and contact time at which the formation of m-TBP is minimum and exerts no effect on the qualitative characteristics of the target p-isomer are determined.

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?

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.