Enthalpies of sorption of glycine from aqueous solutions by carboxylic cation exchangers

The influence of glycine acidity on its interactions with carboxylic cation exchangers in the protonated and deprotonated forms was investigated by the calorimetric and sorption methods. The enthalpies of sorption of glycine on KB-2 and KB-4 cation exchangers at various pH were determined.     

Thermochemical kinetics of the formation of supramolecular compounds of amino acids with carboxylic cation exchangers

The kinetics of sorption of glycine and methionine from aqueous solutions with various acidities on the carboxylic cation exchangers KB-2 and KB-4 in protonated, deprotonated, and copper forms at 298 K was studied by microcalorimetry. In the sorption of the amino acids on the copper forms of the cation exchangers, the heat flux changes its sign. The character of the aliphatic amino acid-carboxylic cation exchanger interparticle interaction depends on the ionic form of the cation exchanger. As determined by the sorption method and IR spectroscopy, the nature of the glycine and methionine sorption sites in the ion exchanger phase changes on passing from the protonated to the copper form of the sorbent.     

Simultaneous purification of sewage from Cd(II) and nonionic surfactant with cation exchanger

The sorption of nonionic surfactant (alkylmonoethers ALM-10), taking place simultaneously with the sorption of Cd(II) in H-form of polyacrylic cation exchangers KB-2 and KB-2-12P was investigated. Increasing the sorption of surfactant the decrease in both the stability of Cd(II) complex with cation exchanger and the equilibrium sorption of Cd(II) was observed. The isotherms of the sorption were measured; the coefficients of intraparticle diffusion (D) were calculated. The integration of the filter filled with polyacrylic cation exchanger into the system of sewage purification is suggested.     

A microcalorimetric study of the sorption of copper(II) on KB-4 carboxyl cationite

The thermokinetics of sorption of copper(II) ions on KB-4 carboxyl cationite in the salt and hydrogen forms was studied microcalorimetrically. The total heat effect of sorption and its dependence on the degree of ionite filling were determined.     

Equilibrium sorption of methionine on carboxyl cation exchangers from solutions of various acidities

The influence of the acidity of solutions of methionine on methionine interaction with KB-2 and KB-4 carboxyl cation exchangers in the protonated and deprotonated forms was studied by the calorimetric, sorption, and spectroscopic methods. It was found that nonexchange methionine absorption occurred from acid solutions, and mixed ion exchange and nonexchange sorption, from alkaline solutions. The enthalpies of sorption of methionine at various external solution pH values were determined. Original Russian Text ? D.V. Ovsyannikova, L.P. Bondareva, V.F. Selemenev, S.I. Karpov, 2009, published in Zhurnal Fizicheskoi Khimii, 2009, Vol. 83, No. 5, pp. 961–966.     

The influence of temperature on the swelling of polyacrylic and polymethacrylic cationites

Temperature was shown to substantially influence the swelling of KB-2e3 polyacrylic and KB-4P2 polymethacrylic ionites cross-linked by triethylene glycol dimethacrylate (TEGDM) and divinylbenzene (DVB). Maximum swelling changes as the temperature increased were observed for the Ca form of the KB-4P2 ionite. Swelling and contraction of polymethacrylic cationite grains as the temperature decreased and increased occurred at equal fairly high rates, whereas the sorption of water by the polyacrylic cationite in the calcium form cross-linked by TEGDM occurred much more slowly than desorption.     

Sorption selectivity of cobalt(II), nickel(II), and copper(II) ions by KB-2E macroreticular carboxylic cation exchanger from aqueous-salt solutions of alkali metals

Sorption selectivity of copper(II), nickel(II), and cobalt(II) ions by KB-2E macroreticular carboxylic cation exchanger in the Na-form from dilute solutions was studied in the target concentration range (0.52.6) 103 M. The equilibrium distribution coefficients of Co²⁺, Ni²⁺, and Cu²⁺ were calculated. The role played by hydration of ions in their sorption by KB-2E cation exchangers is analyzed with consideration for IR spectroscopic, thermal analysis, and scanning electron microscopic data.     

The enthalpy of interaction between an aqueous solution of methionine and carboxyl cationites in the copper form

The influence of acidity of aqueous solutions of methionine on their interaction with carboxyl cationites in the copper form was studied by the calorimetric, sorption, and spectroscopic methods. The distribution of methionine between aqueous solutions and sorbents with the formation of Cu(II) cation complexes in both phases was observed over the pH range 5–12. The enthalpies of interaction between methionine and KB-2 and Kb-4 cationites in the copper form were determined at various pH.     

Determination of the antiplatelet agent. KB-3022, and its metabolite by high-performance liquid chromatography

A rapid, accurate and reproducible high-performance liquid chromatographic method for the simultaneous determination of a new antiplatelet agent, ethyl 2-[4,5-bis(4-methoxyphenyl)thiazol-2-yl]pyrrol-1-ylacetate (KB-3022), and its main metabolite, 2-[4,5-bis(4-methoxyphenyl)thiazol-2-yl]pyrrol-1-ylacetic acid (desethyl KB-3022), in biological fluids has been developed. KB-3022 and desethyl KB-3022 in plasma or urine were extracted with a mixture of n-hexane and dichloromethane (1:1), separated on a reversed-phase C18 column with a mixture of 0.01 M (NH4)2HPO4 (pH 3.0), acetonitrile and isopropyl alcohol as a mobile phase, and quantitated by ultraviolet absorbance measurement at 340 nm. 4-[2-(4,5-bis(4-methoxyphenyl)thiazol-2-yl)pyrrol-1-yl]butyric acid was used as an internal standard. The detection limit of KB-3022 in plasma was 3 ng/ml, and that of KB-3022 in urine and desethyl KB-3022 in plasma or urine was 1 ng/ml. The coefficients of variation for the determination of KB-3022 or desethyl KB-3022 in plasma or urine were below 5.6%. This method was applied to the determination of the plasma concentration of KB-3022 and desethyl KB-3022 after intravenous administration to rats.     

Aspects of the super-equivalent sorption of glycine by cation exchanger KU-2-8

The structure formed in a sorbent during the super-equivalent sorption of glycine by cation exchanger KU-2-8 is optimized via quantum chemical simulation. The differential thermodynamic characteristics of ion exchange and super-equivalent sorption in the studied system are calculated using a thermodynamic approach that allows us to describe the simultaneous exchange and super-equivalent sorption of compounds by ion-exchangers.     

甘氨酸在纳米碳管中的吸附及性质的分子模拟

Molecular Mechanics and Molecular dynamics have been performed to study the adsorption and the diffusion,and optimize the configuration and the energy of glycine molecules in carbon nanotubes. The results of the simulation indicate that the configuration of glycine has been changed,and those varieties will bring on the changes of the biological properties via molecular biology. Carbon nanotube shows relatively strong sorption for glycine molecules,and carbon nanotubes and glycine molecules will produce relatively strong interaction of π-π electrons. The motions between glycine molecules and carbon nanotubes will keep very synergistic status in order to make the system remaining in the state of optimal energy among the simulation.     

Sorption of Cations of the Zn2+-Hg2+-NO3--H2O System by Biomass of Ostreatus Agaricaceae Basidiomycete and KB-4(H+) Cation Exchanger

Sorption of cations of the Zn²⁺-Hg²⁺-NO₃ ^--H₂O system by the biomass of basidiomycete (line 21 Pl. ostreatus f. florida) and by KB-4(H⁺) cation exchanger at pH 1.00 was studied. The results are discussed with regard to the state of cations in the solution before contact with the sorbent, sorbent properties, and sorption behavior of cations.     

The temperature dependence of the exchange enthalpy of calcium and sodium ions on polymethacrylic and polyacrylic cationites

The influence of temperature on the exchange of calcium and sodium ions from solutions of 2.3–2.8 g-equiv/l concentrations on KB-2e4 gel polyacrylic cationite, KB-4P2 and KB-4 gel polymethacrylic cationites, and Purolite C104 polyacrylic cationite was studied over the temperature range 273–400 K. It was shown that, simultaneously with a substantial increase in selectivity with respect to calcium ions, the differential enthalpy of the ion exchange reaction increased linearly on all polyacrylic and polymethacrylic cationites as the temperature grew.     

Mathematical simulation and calculation of the continuous countercurrent process of ion-exchange extraction of strontium from strongly mineralized solutions

The program Countercurrent is developed for the simulation of a continuous ionexchange extraction of strontium from strongly mineralized NaCl and CaCl₂ solutions using a KB-4 carboxylic cation-exchanger in the countercurrent columns. The program allows one to calculate the conditions of Ca and Sr separation depending on the mode of operation at the sorption and regeneration stages, the residual Sr content on the overloaded sorbent, and the Sr separation on incompletely regenerated KB-4. It also makes it possible to find the optimal separation conditions. The program Countercurrent can be also used to simulate other ion-exchange processes.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1034–1037, June, 1993.     

Changes in thermodynamic functions in the two-temperature process of concentration and purification of electrolyte solutions on KB-4P2 polymethacrylic ionite

Temperature dependences of the differential Gibbs energies and sorption enthalpies of water on KB-4P2 polymethacrylic ionite in Ca²⁺, Mg²⁺, Ni²⁺, and Na⁺ forms are determined. It is shown that during the two-temperature concentration and purification of electrolyte solutions, the content of the so-called “free” water in the ionite, the absorption of which by the latter is characterized by very low differential values of the Gibbs energy and enthalpy, changes with a change in the temperature of the polymethacrylic cationite suspension and electrolyte solution. It is established that the rather energy-consuming step of heating the phase of ionite and solution contributes mainly to the enthalpy of this process. Equations for the temperature dependences of the activity of water for solutions of sodium, magnesium, calcium, and nickel chlorides of various concentrations are given.     

The chemical precipitation of nickel on ion exchangers and active carbons

The chemical precipitation of nickel in the form of poorly soluble precipitates in ion exchanger matrices and on active carbons from solutions of nickel chloride and chemical nickel plating electrolytes was studied. The sorption of nickel ions from a solution of nickel chloride occurs most effectively on Purolite D24002 macroporous chelate forming ion exchanger, KU-23-15/100 sulfo cation exchanger, and KU-2-8 gel sulfo cation exchanger. Nickel enters sulfo cation exchangers in the form of counterions, and is adsorbed on Purolite D24002 largely because of complex formation. The subsequent precipitation of nickel in the solid state in matrix pores liberates ionogenic centers, which allows repeated sorption cycles to be performed. After three chemical precipitation cycles under static conditions, the amount of nickel is higher by 170–250% than the ion exchange capacity of the sorbents. The electrolyte of chemical nickel plating contains nickel predominantly in the form of negatively charged and neutral complexes with glycine, which cannot form bonds with the matrices under study. It is therefore reasonable to perform sorption at decreased solution pH values.     

IR spectra of bifunctional α-amino acids sorbed on dehydrated aerosil

IR spectroscopy has been applied to sorption products from the vapors of bifunctional amino acids derived from proteins: glycine, alanine, valine, leucine, isoleucine, phenylalanine, and methionine, which have been used with dehydrated aerosil. Three types of sorption complexes are formed: two hydrogen-bonded ones and a covalent one, which is of ester or mixed anhydride type. The IR spectra and other tests suggest structures for the complexes and formation schemes.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 26, No. 1, pp. 97–102, January–February, 1990. Original article submitted.     

Sorption of small amounts of cobalt(II) on iron(III) oxide

Summary The sorption of small amounts of cobalt(II) on iron (III) oxide has been studied as a function of pH. The mechanism of sorption is discussed. Iron (III) oxide carrier can be used for the preconcentration of small or trace amounts of cobalt(II). The influence of EDTA, glycine,L(+)-arginine andL(+)-cysteine on the sorption yields of cobalt(II) has also been studied.

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Zusammenfassung Die Abhängigkeit der Adsorption geringer Mengen Co (II) an Eisen (III)-hydroxid vom pH wurde untersucht und der Mechanismus der Adsorption erörtert. Eisen (III) oxidträger kann für die Anreicherung kleiner Mengen oder Spuren Co(II) verwendet werden. Der Einfluß von ÄDTA, Glycin, L(+)-Arginin und L(+)-Cystein auf die sorbierte Menge Co(II) wurde gleichfalls geprüft.

     

Sorption of chromium(VI) on ion-exchange resins and sorbents

Sorption of Cr(VI) on AV-17 and EDE-10P anion exchangers, KU-2 and KB-4 cation exchangers, activated charcoal, and foamed graphite (STRG) is studied.     

New Sesquiterpenes from a Taiwanese Marine Sponge of the Genus Parahigginsia

An undescribed Taiwanese marine sponge of the genus Parahigginsia yielded two new sesquiterpene hydrocarbons-parahigginine ( 1 ) and parahigginone ( 2 ). The structures of the new compounds were established on the basis of NMR spectroscopic and mass spectrometric data. Compounds 1 and 2 exhibited moderate cytotoxicity against murine P-388 and human KB-16, A-549, and HT-29 tumor cells.