The limit sorption capacity of active carbon layers with grafted ethanolamine, sodium or potassium glycinate derivatives of PVC with different fractions of components formed on a PVC film was measured under sorption of saturated benzene and water vapor. Sorbents are considered as systems with two porous phases chemically bounded at the interface. The compound to be sorbed is absorbed from the outside by the polymer with the formation of molecular complexes with PVC derivatives and through it passes into carbon to establish the equilibrium state of the distribution under conditions of maximum saturation of the polymer. It is shown that the amount of benzene and water in carbon is less than its capacity. It depends on the nature of the radicals in the PVC derivatives.
A systematization is presented of studies of carbon sorbent functionalization based on chemical modification of the active carbon surface by covalent grafting of macromolecular N-substituted cyclic amines. Thus, porous electron-conducting and luminescent layers grafted onto supports are obtained. The layers can sorb organic compounds. After sorption of acids, hydroxides, and metal salts, the layers become electron- and ion-conducting. Here, hydrogen is formed as in cathodically polarized electrochemical bridges and oxygen is formed as in anodically polarized electrochemical bridges. Principles of layer formation are considered on the surface of the material of cellulose fibers and asbestos cloth, as well as nickel filaments. Specific features of such functionalized sorbents are shown.
Isotherms of benzene and water vapor adsorption onto a composite material made of a layer of active carbon microparticles and cyclic ethanolamine macromolecules bonded to cellulose are measured. The layer is formed by carbon particles with sizes of 2.5–4 µm and grafted porous macromolecular ethanolamine. The latter combines the particles into electron-conducting and luminescent aggregates. The pores in carbon are connected with those of cyclic amines through voids formed by the cycles of oxo-amine groups and conjugated carbon groups on the surfaces of carbon particles. It is found that when the relative pressure is increased, the pores in amines, where the sorbed molecules are combined into host–guest complexes, are filled first. This is followed by estafetee filling of the pores with water or benzene molecules.
Materials are produced with porous layers based on ethanolamine derivatives of PVC or compounds of active carbon with hydroxyethylcyclam derivatives of PVC with aqua complexes of chloride hydrogen cross-linked with the surface of cellulose or asbestos fabric. Their capacity for sorption with respect to hexane and benzene in the saturated vapor and liquid phases is determined. The dependences of current on voltage in a circuit are determined for bridges composed of these materials in air, and in the vapor and liquid phases of benzene and hexane between 3 M HCl solutions and 3 M HCl solutions containing 3 M CaCl 2 . It is established that only H + ions migrate along the bridges between the HCl solutions, and H + and Cl – ions were the only species that moved along the bridges between the HCl solutions containing CaCl 2 . The voltages at which the movement of ions starts are determined, and constants characterizing the conductivity of the layers are found. It is shown that these parameters depend on the structure of a layer, the nature of the fabric, and the medium surrounding a bridge.
A review of methods for the synthesis of new composite materials—electroactive and adsorption-active tissues, their electrochemical properties, and potential applications is presented. These are cellulose or asbestos fibers with porous layers linked to their surface, which consist of cyclam derivatives of PVC filled with active carbon, providing electric conductivity. The H+ or OH– ion conductivity is provided by the H2SO4 or NaOH aqua complexes with aza-crown groups in the pore walls. The high rate of ion transport was demonstrated in air, hexane, benzene, and their vapors. When the current is passed, H2 or O2 is evoluted, or redox transformations of the adsorbed substances occur on the carbon particles. The dependence of the characteristics of the material on its composition and adsorption equilibrium conditions was analyzed. The mechanism of its functioning was suggested. The material was shown to be promising for use in the production of H2 or O2 and acid–base or redox transformations of substances adsorbed from gaseous media or nonaqueous solutions.
A fundamentally new low-temperature method of synthesizing ammonia has been suggested, which is carried out directly in a hydrogen-producing matrix with a material made of cellulose fabric with porous layers of ethanol–cyclam PVC derivatives with activated carbon with aquacomplexes of sodium hydroxide grafted onto its fibers. Complexes of zero-valent nickel and iron within the cyclam structure are formed in the matrix. Hydrogen is formed on the cathode in the course of electrolysis of water from sodium hydroxide aqua complexes on particles of activated carbon as microelectrodes. Hydrogen forms bonds with complexes of zero-valent nickel. Nitrogen from adsorbed air is bound in complexes of zero-valent iron and interacts with active atomic hydrogen. Water is transported to carbon particles through the fabric onto which the layer is grafted. The process is carried out at the room temperature. It has been found that the forming hydrogen is almost completely used. As opposed to the existing methods of synthesis of ammonia, the suggested process is carried out at room temperature and normal pressure.
The synthesis of bilayer materials with porous upper layers composed of PVC hydroxyethylcyclam derivatives filled with carbon and a layer consisting of hydroxyethylcyclam, cross-linked via Si–O–C groups with the silica chains of a developed surface of asbestos fabric, is described. The aza-crown groups in these materials are bound with aqua complexes of H2SO4 or NaOH. The structure of the materials is examined, their adsorption characteristics are determined, and the rate of motion of H+ or OH– ions in electrochemical bridges is measured, while the formation of H2 and O2 in their cathodic and anodic polarization is determined as a function of voltage. It is shown that the upper layer of these materials is adsorption-active and electronand H+- or OH–- conductive, while the bottom layer is only H+- or OH–- conductive; through it, the upper layer is supplied with the H+ or OH– ions needed for the regeneration of the aqua complexes broken down to H2 and O2 on carbon particles.
A material with porous structures formed by jointed aza- and oxa-aza-crowns with peripheral OHgroups is synthesized on the basis of cellulose fabric and PVC transformed into hydroxyethylcyclam. Mesopores are mainly observed on the fiber surface. The specific surface of the material is 6 m2/g; the volume of free space is 0.112 cm3/g. Assuming the internal pores have a disk-like shape, their width is estimated at 2 nm. The material sorbs vapors of aliphatic and aromatic hydrocarbons, alcohols, aldehydes, ketones, amines, amides, nitriles, and sulfoxides. It also swells to a limited degree in organic solvents. When sulfuric acid or sodium hydroxide is sorbed in the pores, compounds of them with H+- and OH–-conducting systems of hydrogen bonds are formed.
A sorbent was synthesized as a cellulose cloth, the fibers of which have nanopores with walls made of cellulose chains and ethanol cyclams. The formation of (NH4)2[NiL(NH3)2Cl2] complexes where L2– is the CH–(O–)–CH–(O–) glucopyranose group was established by chemical analysis and IR and UV/Vis spectroscopy. Using small-angle X-ray scattering and measurement of the partial free space and adsorption capacity, the complex formation in the [Ni(NH3)6]Cl2 concentration range of up to 0.43 mol/L was found to occur in nanopores with the sorption constant K sorb = 15.8. The limiting content of the complexes is 2.63 mmol/g and their effective radius is 0.45 nm. In the concentration range of 0.43–0.91 mol/L, the complexation occurs on the fiber surface, K sorb = 1.85. The effective radius of the complexes is 0.5 nm.
Aquacomplexes of sulfuric acid and sodium hydroxide with aza-crown groups are synthesized in cavities of a sorbent from the porous layer of a PVC cyclam-derivative grafted onto fibers of asbestos fabric. The structure of sorbents with complexes is studied and their adsorption characteristics are determined. It is shown that the affinity of the developed surface toward ethanol, benzene, and hexane depends on the nature of complexes in the pore walls, and the volume of cavities formed as a result of the pores on the developed asbestos surface being coated with networks of aza-crown groups is larger than that of cavities with walls of aza-crown groups in the layers of a PVC cyclam derivative. Indicators of H+- and OH–-conductivity of sorbents with complexes as electrochemical bridges are determined. It is shown that the major part of H+- and OH–-ions moves through complexes with aza-crown groups in the region of cavities formed of pores on the surface of asbestos.
A material with an electrically ОН – -conductive porous layer of cyclam-substituted PVC filled with active coal containing NaOH aqua complexes with aza-crown ligands and cross-linked with the surface of cellulose tissue fibers has been synthesized. The structure of the material was studied. Its sorption capacity in vapors and liquid benzene and hexane, specific resistance, potential of ОН - transfer from solution to layer, and rate constants of ОН – travel in the layer of the material as an electrochemical bridge in vapors and liquid benzene and hexane were determined. The aqua complexes decomposed in the layer with formation of Н 2 during the cathodic polarization of the bridge and О 2 during the anodic polarization; the composition of the complexes was regenerated due to the motion of ОН – .