Inna Khristenko

• V. N. Karazin Kharkiv National University

In the present paper, several test samples with scattered data and outliers were examined by means of different methods for building linear regression equations. This includes ordinary least squares, least absolute deviation, orthogonal distance regression, and the least absolute deviation of orthogonal distance. Also, a variant of the weighted lea...

Hybrid organic-silica material modified by amino groups has been investigated as adsorbent of radionuclides 90Sr, 90Y and 137Cs from aqueous solutions. The sorption ability of the organic-silica material in the pH range of 2–9 with thermostating is studied by static sorption method. Analysis of sorption kinetic curves of radionuclides for aminoxero...

A new silica-organic hybrid material with fixed ionic liquid 1-n-propyl-3-methylimidazolium chloride has been synthesized by the sol-gel method. Its specific surface area is 22 m2 g−1, average pore diameter is 8 nm and pore volume is 0.05 cm3 g−1. According to the results of 13C NMR spectroscopy, the fixed 1-n-propyl-3-methylimidazolium cationic gr...

Surface polarity and acidity are important characteristics of silica-organic materials. Functional groups responsible for the surface acidity and affecting polarity are silanols. Another groups may affect these properties too. The report presents the results of probing surfaces of chemically modified silicas and ormosiles by fluorescent and solvato...

Silica with grafted 1-n-propyl-3-methylimidazolium chloride was investigated as adsorbent for the removal of cobalt(II), copper(II), zinc(II), cadmium(II) and mercury(II) chlorides from alcoholic and aqueous solutions. The adsorption proceeds via the formation of metal-chloride anionic complexes detained near the grafted organic cations as counteri...

Two samples of ormosils, Material 1 and Material 2, synthesized by sol-gel procedure using cation and anion surfactants, have specific surface areas 17±2 and 176±5 m2g-1 and average pore sizes 3.6 and 3.3nm, correspondingly. The proposed method for surfactants removing was better for Material 1 than for Material 2. The model of bidentate binding ad...

Hybrid silica-organic material with fixed n-propylamine groups was prepared by a sol–gel route and characterized by several techniques. Specific surface area of the material was 110 ± 2 m2 g−1, specific pore volume was 0.90 ± 0.01 cm3 g−1, and average pore size was 25 ± 3 nm. The specific concentration of attached amino groups was 3.28 ± 0.05 mmol...

Various basis sets and methods for quantum-chemical calculations are analyzed, and the effect of the number of diffusion and polarization functions on geometry and energy characteristics of systems that simulate the surface of silica modified by aliphatic amines is studied. The contribution from correlation effects and the superposition error of th...

The state of betaine indicators, 2,6-diphenyl-4-(2,4,6-triphenylpyridinium-1-yl)phenolate and 2,6-dichloro-4-(2,4,6-triphenylpyridinium-1-yl)phenolate, on the surfaces of aminosilicas, silica modified with aminodiphosphonic acid, and unmodified silica gel is studied with diffuse reflectance spectroscopy. The normalized polarity parameters are calcu...

The chemisorption of hydrogen ions by silicas chemically modified with aliphatic amines was discussed. The sorption kinetics followed the model of sorption from a semi-infinite solution, with sorption being of a two-stage nature. The first stage, involving the overwhelming majority of sorption centres, was very fast. In contrast, the second stage w...

New chemically modified silicas – macroporous and pyrogenic – with covalently bonded chelating groups of N-benzoyl-N-phenylhydroxylamine (SiO2–BPHA) were obtained in three-step surface reaction. From elemental analysis, metal chemisorption and pH titration the concentration of bonded groups was determined as 0.076 and 0.21 mmol g−1 for Silochrome a...

A study is made of sorption of H+, Mn2+, Co2+, Ni2+, Cu2+, and Zn2+ ions by silica chemically modified with iminodiacetic acid. The compositions and stability constants of the products formed in reactions involving iminodiacetic acid are determined. The influence of the ionic strength of the aqueous solution on the equilibrium constants is elucidat...

Chemisorption of hydrogen and transition-metal ions on silica chemically modified with 2-aminomethylquinoline (2-AMQ) is studied. The protonation constants of the grafted ligand and stability constants of anchored metal complexes are determined based on quantitative physicochemical analysis. The effects of aqueous base electrolytes on the compositi...

Silica chemically modified with N-benzoyl-N-phenylhydroxylamine was studied as a compound promising for sorption concentration and solid-phase spectrophotometric analysis of Fe(III). The conditions providing almost complete recovery of Fe(III) from solution with this sorbent were determined. An analytical procedure including sorption concentration...

Equilibrium of dissociation and homoconjugation of molecules of benzoylphenylhydroxylamine (BPHA) grafted on a silica surface was studied in the range of ionic forces of aqueous solutions 0.1-1.0 mol/1 at 20°C. Energy inhomogeneities of samples of complexing silica were examined. The experimental results were interpreted in terms of the concept of...