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Приведены данные по микроэлементному составу лиственницы сибирской (Larix sibirica Ledeb.), произрастающей в пределах Приольхонья – составной части Прибайкальского национального парка. Показано, что уровни накопления микроэлементов в золе веток лиственницы характеризуются в целом низкими или незначительно (в среднем до трех раз) превышающими фон значениями. В целом содержание микроэлементов ниже кларковых концентраций в золе наземных растений. Пространственное распределение микроэлементов соответствует таковому в питающем их субстрате. Предполагается, что в исследуемом районе ведущую роль в ассимиляционных процессах играет корневое питание, а атмосферное поступление элементов имеет подчиненное значение. Приведенные содержания микроэлементов и их балансовые соотношения могут быть реперными при оценке санитарного состояния лесных компонентов экосистем Прибайкалья.

Определены посевные качества и содержание общего и белкового азота в семенах ели сибирской (Picea obovata Ledeb.), сосны обыкновенной (Pinus sylvestris L.), лиственницы сибирской (Larix sibirica L.) и лиственницы Гмелина (Larix gmelinii Rupr.) из разных регионов Восточной Сибири. Выявлено, что наибольшее содержание общего и белкового азота имеют семена сосны обыкновенной, эти же семена показали наилучшие посевные качества. Обнаружена высокая корреляция потенциальной всхожести семян изучаемых хвойных растений с содержанием в них общего азота. Показано, что посевные качества семян и содержание азота в них варьируют в зависимости от региона сбора семян и значительно коррелируют со среднеиюльскими температурами регионов и величиной периода вегетации.

The modeling of a low temperature nitrogen adsorption in graphite mesopores with rectangular sections having the aspect ratio of the side lengths more than 7:1 has been executed by using the grand canonical Monte Carlo (GCMC) method. The adsorption branches of obtained GCMC isotherms were processed with the purpose of calculation of the formal pore size distributions (PSDs) by the nonlocal density functional theory (NLDFT) and Derjaguin-Broekhoff-de Boer (D-BdB) method. It is shown that NLDFT underestimates the sizes of the model rectangular mesopores though gives good estimations of specific surface area and volume of the pores. Also, it is shown that D-BdB method very strongly underestimates specific surface area and overestimates total volume of pores. PSDs obtained from D-BdB method have a very wide distributive interval of apparent sizes and brightly expressed bimodal forms. Such completely wrong information about the size of the investigated model pores is a consequence of the macroscopic assumption of the D-BdB theory about the constancy of the capillary condensate density in pores at various pressures.

Porous carbon materials with tailored pore texture can be prepared by evaporative drying and pyrolysis of resorcinol-formaldehyde aqueous gels. The pore size is easily controlled by the pH of the precursor solution. These materials, called "carbon xerogels", can be used as catalyst supports, like activated carbons. Since the texture of these materials is adjustable, it is possible to avoid diffusional limitations that are often encountered when a microporous activated carbon is used as support by choosing a support with the appropriate pore size. The meso- or macropore size of carbon xerogels can be enlarged so as to simplify the reactant diffusion, which leads to better catalytic performances.

Oxidations of alcohols into carbonyl functionalities are key reactions in the synthesis of fine chemicals. The need to substitute stoichiometric oxidations (using mineral oxidants) with "green" oxidations using benign oxidizing agents like molecular oxygen or hydrogen peroxide has been often emphasized. Supported noble metal catalysts, e.g. Pd/C or Pt/C are known to catalyse the oxidation of alcohols in the presence of molecular oxygen. It was previously reported that benzyl alcohol (Bzol) can be very selectively oxidized to benzaldehyde (Bzal) in dioxane, whereas the use of a 50/50 mixture of dioxane and alkaline aqueous solution yielded benzoic acid (Bzoic) by further oxidation of Bzal. In this work, we examined the effect of the activation treatment of the synthetic carbon and of the method of deposition of the metal on the characteristics of the supported metallic catalyst and its activity in this reaction. The highest dispersion and best catalytic performances were obtained by impregnation with hexachloroplatinic acid of a CO₂ activated carbon.

A systematic investigation of carbon nanotubes (CNT) and nanofibre (CNF) growth in terms of structures of carbon nanomaterials and growth rates by chemical vapour deposition is summarized. Different catalysts such as unsupported Fe₃O₄ and supported Ni, Fe and NiFe catalysts and different carbon sources such as CO, CO/H₂, CH₄/H₂, C₂H₆/H₂ and C₂H₄/CO/H₂ have been applied. This short review has been addressed to identify the principles for controlled synthesis of carbon nanotube or nanofibre with well-defined structures. The production of relatively high yields of defined structures is obtained. The Ni catalyst produces almost exclusively fishbone CNFs, while the supported Fe catalyst produces multiwall CNTs (MWCNTs). The NiFe catalyst can give a structure intermediate of the two. Unsupported Fe₃O₄ results in the platelet structure. The diameter of the produced structures holds information on the growth mechanism. The diameters of the MWNTs are always smaller than the growth catalyst particles, while the fishbone CNFs always have larger diameter than the growth catalyst. The structure and growth rate reflect the different reactivity of the metals and the dependence on surface orientation of the catalyst particles. Higher temperature and lower partial pressure yield smaller diameter MWNTs with fewer walls and a larger inner hollow core. The space velocity and thereby the H₂ partial pressure in the reactor has been identified as the most important parameter for scale-up of the reactor.

Carbon-based catalysts in powder, briquette and monolith forms have been prepared. Powder and briquette samples have been obtained from low-rank coal whereas monolith samples were prepared by coating cordierite monoliths with a blend of two polymers, namely, furan resin and polyethylene glycol. Vanadium was impregnated in these carbon-based catalysts by equilibrium adsorption using the ashes of a petroleum coke (PCA) as precursor and they were tested in the SCR of NO at low temperature. PCA contains around 23%V, 3 % Fe and 3 % Ni among other transition metals and this use is an undeniable good way for its revalorisation. As-prepared catalysts have demonstrated a considerable efficiency which was enhanced by pre-oxidizing treatments and an increase of vanadium loading. The presence of oxygen surface functionalities is of key importance to achieve an adequate distribution and fixation of the active phase while an excess in vanadium loading can even cause pore blockage decreasing the total efficiency. External diffusion and pressure drop coefficients were calculated for the three kinds of catalysts. As expected, powder catalyst shows the highest pressure drop while briquette and monolith samples show lower pressure drop values with no sign of diffusion limitations. For this reason, these structurated catalysts are considered to be more suitable for industrial applications.

Dispersed palladium catalysts supported on carbon were prepared using different strong oxidants for preliminary treatment of the support. The surface properties of carbon and its ability to give place to highly dispersed Pd were discussed. Oxidative pre-treatment was shown to promote the dispersion significantly increasing the catalytic activity.

We have supported platinum on a commercial activated carbon with different loadings. The as-prepared catalyst has been used for the dehydrogenation of decalin in a batch-type reactor under boiling and refluxing conditions. The impact of some variables such as temperature, % Pt loading and decalin/catalyst ratio was studied using experimental design tools. The experiments carried out enable us to find the decalin to catalyst ratio which led to the best catalytic performance in our system.

Influence of the process parameters on porous structure of monolithic and spherical resorcinol-formaldehyde (RF) carbon aerogels prepared by supercritical acetone and carbon dioxide drying of alcogels, followed by carbonization is presented. The prepared organic RF aerogels were carbonized at 600 ^oC to form carbon aerogels and their porous structure was characterized by nitrogen adsorption. It was stated that synthesis parameters of RF organic aerogels (catalyst type, gel curing time, R/C ratio, resorcinol concentration in water) and drying method (low- or high-temperature supercritical drying) strongly influence textural parameters of the final carbon aerogels. Application of KOH in RF aerogel preparation allows obtaining carbon aerogels of the most advantageous parameters irrespective of the used drying method. Elongation of curing time of RF gels results in an increase in specific surface area and total pore volume of the carbon aerogels obtained both in the course of low- and high-temperature drying. Low-temperature supercritical drying of RF aerogels gives carbon materials of more advantageous texture parameters in comparison to carbon aerogels obtained in high-temperature supercritical drying.