Integrated processing of anthracite into sorption materials

The possibility of using anthracite to produce activated carbon in the form of microporous and mesoporous anthracite, a cation exchanger, and composite sorption materials was analyzed and the porometric properties of a variety of sorption materials based on anthracite from the Donets coal basin were studied. A flowsheet for integrated processing of anthracite to give a set of four products was composed.     

Factors determining the catalytic properties of active carbons in some acid-base and redox reactions

The results of the authors’ investigation of the catalytic properties of active carbons in acid-base and redox reactions are summarized. The general principles of controlling the activity of carbon catalysts are described, the main factors in the catalytic processes occurring on these catalysts are revealed, and new ways of using the catalytic properties of carbon sorbents from various sources are considered. The article was translated by the authors. Published in Russian in Kinetika i Kataliz, 2007, Vol. 48, No. 4, pp. 643–648.     

Morphological and chemical features of nano and macroscale carbons affecting hydrogen peroxide decomposition in aqueous media

Stable film-forming nanocomposite particles with diameters ranging from 120 to 300 nm, based on polybutylmethacrylate (PBMA) and cellulose whiskers in water dispersions, were successfully synthesized in one step through mini-emulsion polymerization. The nanocomposite dispersion with a solid content of 25 wt.% and up to 5 wt.% of nanofiller loading was prepared by in situ polymerization, in the presence of the whiskers using dodecylpyridinium chloride (DPC), as a cationic surfactant, and 2,2-azobis(isobutyronitrile) (AIBN), as initiator. The electrostatic interaction between the positively charged droplets and negatively charged whiskers ensured the anchoring of the nanofiller around the polymer particles. The ensuing dispersions were characterized by Dynamic Light Scattering (DLS), ζ-Potential Measurements, and Field-Emission Scanning Electron Microscopy (FE-SEM). After the film formation process, the nanocomposite film exhibits a high transparency, denoting the good dispersion of the whiskers throughout the matrix.     

Electrokinetic potential of multilayer carbon nanotubes in aqueous solutions of electrolytes and surfactants

The effect of electrolytes with single-, double- and triple-charged counterions, as well as cationic (cetyltrimethylammonium bromide) and anionic (sodium dodecyl sulfate) surfactants, on the electrokinetic potential of multiwall carbon nanotubes prepared via catalytic pyrolysis of propylene in a gas phase according to the CCVD technology has been studied. It has been shown that the influence of different electrolytes on the electrophoretic mobility of the nanotubes does not differ essentially from their effect on the behavior of well-studied inorganic dispersed particles; i.e., the dependence of the absolute values of the ζ-potential on the concentration of a 1: 1 electrolyte passes through a maximum and the introduction of double-charged counterions dramatically reduces the ζ-potential, while the addition of triple-charged cations and a cationic surfactant causes charge reversal of the nanotube surface. The adsorption of sodium dodecyl sulfate in a neutral medium increases the negative ζ values; this effect evens out in the presence of an alkali due to a rise in the electrostatic repulsion between surfactant anions and nanotube surface, which bears a high negative charge resulting from the dissociation of surface functional groups.     

Structural and sorption characteristics of carbon adsorbents from waste formed in wood processing

The structural and sorption characteristics of microporous sorbents from industrial lignin with respect to some toxic substances, Pb²⁺, Cd²⁺, Cu²⁺, and NH⁺ ₄ ions, and also the possibility of accumulation of methane on these carbons were studied. Simple procedures for modification of the carbon surface to improve the sorption power of the carbons were suggested.     

Effect of combined activation on the preparation of high porous active carbons from granulated post-consumer polyethyleneterephthalate

Activated carbons were prepared from granulated post-consumer PET by combined activation including heat treatment with sulphuric acid (chemical activation) followed by steam activation. The effect of activation time, temperature, impregnation coefficient in the activation process was studied in order to optimize those reception parameters. One of the most important parameter in combined activation of crushed PET was found to be impregnation coefficient. It was defined that the optimal impregnation coefficient is equal 28%. Activation temperature is another variability which has a significant effect on the pore volume evolution. The increasing of activation temperature enhances the surface area and pore volumes of active carbons. The yield of final product which composes of nearly 15% is the factor limited the activation temperature above 800 °C. Textural characteristics of the samples were carried out by performing N₂ adsorption isotherm at −196 °C. The obtained active carbons were mainly micro- and mesoporous and with BET apparent surface areas of up to 1030 m²/g. The adsorption capacity on methylene blue reaches 1.0 mmol/g, the sorption activity on iodine comes to 77%.     

Porosity and sorption properties of activated carbons prepared from anthracite by steam-air activation

Fundamental aspects of the steam-air activation of anthracite from Donets coal fields were studied. The effect of the flow rate of moistened air on the development of a porous structure and the sorption properties of the adsorbents obtained were examined.