Исследована адсорбция ряда соединений, обладающих свойствами кислот, оснований и амфотерных соединений, на пористом микродисперсном детонационном наноалмазе (ПМДН) из водных растворов. Из анализа результатов адсорбции кислотных и основных красителей на поверхности ПМДН следует, что на поверхности сорбента имеются как основные, так и кислотные группы, с которыми способны вступать во взаимодействия молекулы органических кислот, оснований и амфотерных соединений. Обработка исходного образца кислотой или основанием приводит к уменьшению адсорбции кислотных и основных красителей, что может быть связано с удалением примесей с поверхности ПМДН, с которыми способны взаимодействовать кислотные и основные соединения.

Adsorption of water-soluble vitamins, including riboflavin (В2), nicotinamide (PP, B3), pyridoxine (B6), cyanocobalamine (В12) from water-organic solutions on microdispersed sintered detonation nanodiamond (MSDN), modified in different ways, was studied using high-performance liquid chromatography (HPLC). The effect of composition (from 5% to 80 v/v % of CH3CN) and рН (рН 2.7/6.0) of mobile phase, as well as temperature of chromatographic column (tc = 45/65 °C) on vitamins adsorption was studied. Nonlinear dependences of the sorbate retention factors on the acetonitrile content in the mobile phase are found out, indicating the variation of specific and non-specific interactions of vitamins with MSDN surface. Based on the obtained results, the conditions for chromatographic separation of the mixture of water-soluble vitamins in isocratic mode of HPLC on MSDN are optimized.

Adsorption properties of γ-Al2O3 modified with Co (5 and 10 wt %) and Co (5 wt %) species are investigated by dynamic adsorption. N-hexane, n-heptane, n-octane, benzene, toluene, ethylbenzene, chloroform, and diethyl ether were used as test adsorbates. Adsorption isotherms were measured, and isosteric adsorption heats were calculated for the indicated sorbates. It was shown that the adsorption isotherms of all the adsorbates and at all the temperatures of measurements on γ-Al2O3 modified with Co (5 wt %) and CoO (5 wt %) nanoparticles located above that recorded for the initial γ-Al2O3 sample. It was established that the surface of modified γ-Al2O3 possessed mainly electron-accepting properties. The 5% Со/γ-Al2O3 and 5% СоO/γ-Al2O3 nanocomposites exhibited the greatest adsorption capacity relative to aromatic hydrocarbons.

Microdispersed sintered detonation nanodiamonds (MSDN) with different surface chemistry were characterized using X-ray diffraction method, energy dispersive spectroscopy (EDS) and adsorption of ionogenic and nonionogenic compounds in static and dynamic (with HPLC instrumental design) conditions. It was shown that for MSDN, conditioned with 3 × 10 −3 M H 3 PO 4 , adsorption of substances with basic properties increases by 13.5–22.0, while washing of MSDN with 1.3 × 10 −5 М ammonium hydroxide decreases adsorption of bases as a result of modification of ionic state of functional groups at the surface. It is found that concentration of H 3 PO 4 solution significantly effects on adsorption of ionogenic organic substances. The effect of organic solvent is investigated by obtaining of isotherms of excessive adsorption of pyridine on MSDN from solutions in water and acetonitrile under static conditions. It is found that the equilibration of MSDN with acid solution activates its surface for adsorption of pyridine that may be due to desorption of substances blocking acidic adsorption centers. It was shown that usage of buffers containing additives of ammonium, potassium and sodium electrolytes results in decrease of adsorption of basic molecules, which is explained by competitive adsorption of cations on dissociated carboxyl functional groups on the surface of MSDN.

The adsorption properties of nanocomposites based on γ-Al2O3 modified with CeO x , Au/CeO x , and Pd/CeO x nanoparticles with contents of deposited metals ranging from 0.07 to 1.71 wt % are investigated by means of dynamic sorption method. n-Alkanes (C6–C8), acetonitrile, diethyl ether, tetrahydrofuran, and dioxane are used as test adsorbates. Adsorption isotherms are measured, and the isosteric heats of adsorption of a number of test adsorbates are calculated. Electron-donor and electron-acceptor characteristics of the surfaces of γ-Al2O3-based nanocomposites are estimated. It is shown that Au(0.1%)/CeO x (0.07%)/γ-Al2O3 nanocomposite, which has the lowest content of nanoparticles of the deposited metals, has the highest adsorption activity.

Adsorption of a number of aniline and pyridine derivatives from water-acetonitrile solution on ultradispersed diamonds was investigated using dynamic sorption method. It was shown that the nature of functional substitutes and their position in molecules of nitrogen-containing compounds of pyridine and aniline have a pronounced effect on adsorption on the surface of ultradispersed diamonds. The dependence of chromatographic sorbate retention on the content of mobile phase could be described by a curve with a minimum. Such nonlinear relationship was explained by the change in the ratio of contribution of specific and non-specific interaction to the sorbate retention that was observed on varying the volume content of an organic component in mobile phase. The influence of temperature on sorption of pyridine and aniline derivatives on ultradisperesed diamonds was investigated. The changes in enthalpy and entropy factors of competitive sorption of sorbates were determined.

Adsorption of phenols on microdisperse sintered detonation nanodiamond (MSDN) from water–acetonitrile solutions was investigated using high performance liquid chromatography (HPLC). Parabolic dependence between retention and organic solvent content in mobile phase was observed. The influence of physicochemical characteristic solutes including molecular volume (V), dipole moment (μ), hydrophobicity (logP), polarizability (α) and molecular refractivity (MR)) of phenols on their adsorption from water–acetonitrile solutions was investigated. Single- and multi-parameter correlations between retention factor and various physicochemical characteristics of sorbates were obtained. The effect of column temperature on adsorption of phenols on UDD was investigated. The changes in ΔH and ΔS for competitive adsorption of the test sorbates were determined.