Himiâ tverdogo topliva

Supported iron catalysts based on a carbon-containing material, biochar obtained by the hydrothermal carbonization of biopolymers (cellulose and lignin), were studied. The catalytic systems showed high activity in the Fischer–Tropsch synthesis. A composition of C5+ liquid products, uncharacteristic for ironcontaining catalysts, characterized by high isoalkane content (up to 55%) was recorded. This fact was discussed in the context of the theory of bifunctional centers proposed by A.L. Lapidus with coworkers. It was suggested that the active centers of the test catalysts can be considered bifunctional (a carbide phase and an oxide phase). A correlation between the Fischer–Tropsch synthesis data on the test catalysts and the data obtained by Lapidus and coworkers on cobalt-containing catalysts was shown.

The effect of treatment of a freshly reduced cobalt catalyst with oxygen and ammonia on its properties in the Fischer–Tropsch synthesis was studied. It was shown that treatment with small amounts of catalytic poisons helped to increase the selectivity of the catalyst with respect to the formation of target products,
linear C5+ hydrocarbons. The observed effect can be explained by partial blocking of the sites of direct CO hydrogenation to methane and modification of Lewis acid sites. The data obtained were consistent with the concept of the two-center surface model of Co catalysts for the Fischer–Tropsch synthesis and the theory of astoichiometric components of catalytic reactions.

The reactions of humic acids in a pure form and in the composition of coal with sodium percarbonate occurring on solid-phase mechanochemical treatment were compared. Analysis for CHNO, IR spectroscopy, and potentiometric titration were used to study changes in the composition of humic acids mechanochemically
treated after isolation from brown coal. The sorption properties in relation to heavy metal ions (Zn2+, Cu2+, and Cd2+) and their changes as a result of the treatment were studied. The results were correlated with data similar to those for humic acids in coal that underwent mechanochemical treatment. It was demonstrated that, at present, an increase in the yield of humic acids and the concentrations of phenolic and carboxyl groups in brown coal as a result of treatment with sodium percarbonate can be explained by the oxidation of fractions other than humic acids in the organic matter of brown coal.

A method for producing granular carbon adsorbent by stirring a suspension of soot in a solution of naphthalene (in heptane) in the presence of sulfuric acid was proposed. Experimental research together with mathematical processing of the results made it possible to propose a mechanism for the formation of spherical carbon granules from soot and naphthalene: in the course of intense mixing in the presence of concentrated sulfuric acid, a binder material was formed from naphthalene, and it was adsorbed on the surface of soot particles. The resulting particles with a thin layer of binding material on their surface stuck together in the field of centrifugal forces to form larger particles, which ultimately acquired a spherical shape and had a size of up to 5 mm. A comparison of the resulting carbon granules (from soot and synthetic pitch) with granules prepared
by mixing soot and petroleum pitch showed that the proposed adsorbent had specific surface area and mechanical strength greater by factors of 1.5–2.