Sorption Activity of “Taunit”-Series Carbon Nanomaterials

The work is dedicated to finding new modern adsorbents in order to intensify production technologies of vodka and improve the quality of finished products. In the present paper, the technology of carbon nanotubes (CNTs) synthesis is described; CNTs “Taunit”-series were obtained via chemical vapor decomposition at NanoTechCenter Ltd. (Tambov, Russia). The CNTs properties were determined by scanning electron microscopy, nitrite adsorption, laser diffraction, and thermogravimetry. The principle characteristics measured for the water-alcohol mixture were as follows: rigidity, alkalinity, oxidability, volume fraction of methyl alcohol, weight concentration of acetaldehyde, and 2-propanol and organoleptic parameters, found by using gas-chromatographic analysis. The studies performed demonstrate that the “Taunit”-series carbon nanostructured materials can be effectively used for filtering water-alcohol mixtures in the vodka production.

High-Yield Synthesis of Cubic and Hexagonal Boron Nitride Nanoparticles by Laser Chemical Vapor Decomposition of Borazine

We report a new method for the synthesis of boron nitride nanostructures (nBN) using laser chemical vapor decomposition (LCVD). Borazine was used as precursor and excited with two simultaneous radiations, the fundamental and second YAG laser harmonics. If only one of the two radiations is employed, no reaction takes place. Abundant BN powder is obtained after one hour of laser radiation. The BN yield obtained with the LCVD technique is about 83% by weight. The BN material was characterized using scanning electron microscopy, transmission electron microscopy, electron energy loss spectroscopy, Raman spectroscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. They all indicate that the BN powder consists of a mixture of hexagonal and cubic BN nanostructures. No other BN phases or stoichiometries were found. The size of the resulting BN nanostructures is in the range of 20–100 nm and their B : N composition is 1 : 1. A simplified mechanism involving laser-excited states followed by photoinduced removal of hydrogen is proposed to understand the synthesis of BN nanopowder by LCVD of borazine.

Topography and nanomechanical properties of Pd-C films

Atomic force microscopy (AFM) topographical studies and results of nanoindentation experiment for several palladium-carbon films (Pd-C film) deposited on various substrates and with varying palladium content are presented. Pd-C films were prepared by a physical vapor decomposition (PVD) process and next were modified by a chemical vapor decomposition (CVD) method to obtain carbonaceous porous structure with dispersed palladium nanograins and a variation in roughness.The dependence of film topography on the kind of substrate such as Al2O3, Mo polycrystalline foil and fused silica was studied by AFM. Nanomechanical properties such as hardness and the reduced indentation modulus were determined by nanoindentation. A comparison of these values for films with different Pd content deposited on various substrates is presented.