Геометричне та механо-сорбційне модифікування високодисперсного кремнезему в умовах газового дисперсійного середовища

Methods of geometric and solvate-stymulated mechano-sorption-activated modification of fumed nanosilica in the gaseous dispersion media were developed and used to prepare functionalyzed nanofillers for polymeric systems. Non-volatile high- and low-molecular weight compounds (such as polymers, organic bioactive compounds, organic and inorganic salts) can be used as modifiers of nanofillers.Були описані геометричне та сольвато-стимульоване механосорбційне модифікування високодисперсного кремнезему в умовах газового дисперсійного середовища. Такі способи модифікування дозволяють одержувати функціоналізовані наповнювачі полімерних систем на основі нанорозмірного кремнезему. Для модифікування можна використовувати нелеткі високо- та низькомолекулярні органічні сполуки – полімери, біологічно активні сполуки, органічні солі, а також неорганічні солі

In vitro phosphorylation as tool for modification of silk and keratin fibrous materials

An overview is given of the recent work on in vitro enzymatic phosphorylation of silk fibroin and human hair keratin. Opposing to many chemical "conventional" approaches, enzymatic phosphorylation is in fact a mild reaction and the treatment falls within "green chemistry" approach. Silk and keratin are not phosphorylated in vivo, but in vitro. This enzyme-driven modification is a major technological breakthrough. Harsh chemical chemicals are avoided, and mild conditions make enzymatic phosphorylation a real "green chemistry" approach. The current communication presents a novel approach stating that enzyme phosphorylation may be used as a tool to modify the surface charge of biocompatible materials such as keratin and silk

Physicochemical and Technological Aspects of the Hydrothermal Modification of Complex Sorbents and Catalysts. Part I. Modification of Porous and Crystalline Structures

This paper deals with the hydrothermal modification of the physicochemical properties of complex mineral sorbents and catalysts. The hydrothermal modification of alumina, magnesia, ferric oxide and zirconia/silica hydro- and xero-gels as well as other complex adsorbents obtained by the coprecipitation and mechanical stirring of suitable components is discussed. The paper deals with the following topics: (a) the physicochemical bases of the hydrothermal method; (b) methodological and technological problems of the hydrothermal treatment of adsorbents; (c) hydrothermal modification of porous structure parameters (specific surface area, pore volume and size); and (d) characteristics of the hydrothermal modification of the porous structure of multicomponent adsorbents and catalysts. In addition, the mechanism of the hydrothermal modification of the porous structure of composite materials is discussed

Physicochemical and Technological Aspects of the Hydrothermal Modification of Complex Sorbents and Catalysts. Part II. Modification of Phase Composition and Mechanical Properties

Two main ways of applying the method of solid hydrothermal treatment have been considered: (a) hydrothermal modification of polycrystalline adsorbents and catalysts; and (b) hydrothermal synthesis of materials possessing regular porosity (zeolite-like, laminar and others). Modification processes of phase composition and mechanical properties of complex adsorbents and catalysts were discussed. The essential features of hydrothermal crystallization in multicomponent systems have been presented

Studies of the Effects of Aerosilogel Modification by Organic Acids under High Pressures

Preliminary studies of silica surface modification by means of some organic acids under high reagent pressures were carried out. The reaction took place in a steel autoclave. Suitably granulated aerosilogel and acetic, mono- and trichloro-acetic as well as sulphosalicylic acids were used. Physical and chemical adsorption processes were checked by infrared spectroscopy, thermogravimetry and Potentiometric titration. The specific surface area and total volume of pores of the prepared samples were determined. The studies showed some possibilities of attaching organic radicals containing an acid group to the silica surface. This process can be accomplished in one stage

Thermal and calorimetric investigations of titania–silica composites

The paper presents the studies of effects of TiO 2 amount differentiation on the structural and thermal properties of titania–silica complex oxides prepared by chemical vapor deposition of TiCL 4 onto the Si-40, Si-60, and Si-100 silica gels. The mesoporous materials, characterized by a varied pore structure with highly developed surface and large pore volume, were obtained. The porous structure of materials under investigations was characterized by the low-temperature nitrogen adsorption–desorption method as well as by power spectral density calculated from the calorimetric investigations of water confined in the pores. Moreover, the thermodesorption of water using the quasi-isothermal thermogravimetry was used to characterize their thermal and surface properties. The adsorbed water layers and the concentration of weakly and strongly bound water as well as the surface free energy on the adsorbent–water interfaces were calculated. It was stated that the increase of titania content causes a gradual decrease of specific surface area and has a significant effect on the porous structure formation. The water thermodesorption from the surface proceeds in few stages because of the porosity created by TiO 2 . The decrease in the total surface free energy (Δ G Σ ) can be observed with the increasing TiO 2 content. The largest Δ G Σ value at the adsorbent/strongly bound water interface is exhibited by the adsorbents of Si-100 series. The lowering of the freezing/melting points of water contained in the pores of the studied materials is strongly connected with their porous structure

Hydrothermal and mechanochemical synthesis of crystalline CaCO

Mechanochemical and microwave-assisted hydrothermal (MicroWave Treatment [MWT]) procedures were applied to prepare crystalline CaCO 3 . Mechanochemical process was carried out at different speeds of rotation (500 or 850 rpm/min), different duration times (30 or 60 min) and in the aqueous suspensions or in dry state. MWT synthesis was conducted in a saturated water vapour or under the layer of water. The crystalline and porous structures of the prepared samples as well as their morphology were investigated using N 2 adsorption, X-ray diffraction and scanning electron microscopy methods. As a result, the calcium carbonate samples in the form of calcite were obtained. The materials prepared by the mechanochemical route performed in the aqueous suspension are characterized by smaller crystallite sizes as compared to those obtained without the addition of water. The samples obtained hydrothermally have the largest size of crystallites. Powders prepared by energetical milling possess higher values of specific surface area in relation to the parameter for those synthesized hydrothermally. In the process of hydrothermal treatment, macroporous structure of the prepared materials is created. With the increasing specific surface area of the sample, the size of the crystallites decreased

Solid phase extraction of explosives on Ni-doped carbosils prepared by mechanochemistry

The article presents the application of two sets of Ni-doped carbosils in the solid phase extraction of explosives. The adsorbents were prepared by two different methods. The first set of carbosils was obtained by mechanochemical deposition of potato starch and nickel salt on the surface of silica gel, and subsequent carbonization. The second set of carbosils was obtained from the same precursors and under quite similar conditions, i.e. with the exception of mechanochemical deposition of potato starch replaced by the gelation step. The prepared adsorbents were applied in solid phase extraction of explosive nitrate esters, and nitroaromatics from aqueous solutions. The adsorption and desorption steps were evaluated separately. It was found that textural properties, influenced by carbon deposit and nickel content, have a large impact on the solid phase extraction results. The recovery rates obtained onto carbosils prepared by mechanochemical method are approximately thrice as high as those observed for carbosils prepared by gelation method. It was shown that the composites with moderate nickel content can be used as effective materials for extraction both of aliphatic and aromatic explosives

Characterization of the Porous Structure of HPLC Packings Based on Di(-Acrylic Phenyl)Sulphone and DVB

Studies of the porous structure of the polymeric microspheres synthesized from di( p -acrylic phenyl)sulphone (DAS), ( p -hydroxyphenyl- p -acrylic phenyl)sulphone (HAS) and divinylbenzene (DVB) are presented. The porous structure was characterized by the nitrogen adsorption method, inverse exclusion chromatography and atomic force microscopy. To describe the tendency of the microspheres to swell, the swelling propensities and the swellability coefficient were also determined. The results show that both polymers studied can be used as packing materials in chromatography. Their porous structures are relatively stable since they are characterized by a high degree of crosslinking. In addition, the polymer ASP–OH containing reactive hydroxyl functional groups provides a convenient starting material for chemical modifications