The yield and properties of solid and liquid products of hydrothermal treatment of organic waste were determined with cheese, meat, and apples as an example. The solid products of hydrothermal treatme

This study is devoted to the hydrothermal oxidation of aluminum—the exothermic process in which hydrogen and aluminum oxide (or hydroxide) are produced. In this work, the influence of the chemical purity of aluminum on the conversion degree of coarse aluminum at hydrothermal oxidation was studied. Distilled water and coarse granules of aluminum with an average size of ~7–10 mm and three different aluminum purities—99.7, 99.9, and 99.99%—were used in the experiments. The oxidation experiments were carried out inside a 5 liter autoclave in an isothermal mode at temperatures from 200 to 280 °C, with a step of 20 °C. The holding time at the set temperature varied from 4 to 10 h. It was shown that the chemical purity of aluminum considerably influences the oxidation kinetics. More chemically pure aluminum oxidizes much faster, e.g., at a temperature of 280 °C and a holding time of 10 h, the conversion degree of granules with a chemical purity of 99.9% and 99.7% was less than 2%, while 99.99% aluminum was almost fully oxidized. The conversion degree of 99.99% aluminum decreased with the reduction in temperature and holding time, to 66–68% at 280 °C, 4 h, and 2–3% at 200 °C, 10 h.

The fractional and chemical composition of bio-oil and its gasoline fraction, obtained by hydrothermal liquefaction of Arthrospira platensis biomass, was studied. The bio-oil yield was 34.6%, the heat of combustion of bio-oil was 33.4 MJ kg-1, and the gasoline fraction yield was 28.8%. The content of carbon and hydrogen in the gasoline fraction of the bio-oil is appreciably higher than in the initial bio-oil, and the calorific value of the gasoline fraction is 3.87 MJ kg-1 higher than that of the initial bio-oil. With respect to the carbon and hydrogen content, the gasoline fraction of the bio-oil is close to motor fuels, differing from them in the higher content of nitrogen, oxygen, and sulfur. Fractional distillation of bio-oil decreases the content of high-molecular-mass condensed compounds in the product.

Mg–air batteries have high theoretical energy density and cell voltage. Their use of environmentally friendly salt electrolyte and commercially available magnesium materials determines their acceptable technical and economic efficiency, safety, and ease of operation. However, the practical applicationsof Mg–air batteries arevery limited due to the polarization of magnesium anodes and the batteries’ low Faraday efficiency. In this study, we considered the possibility of designingan Mg–air battery withincreased power by adapting engineering solutions developed for an Al–air battery with alkaline electrolytes. To increase the specific power of the battery, it was proposed that the internal resistance of the battery maybe reduced using a concentrated salt electrolyte. We investigated the discharge performance of a commercial alloy of AZ31 type in 15 wt.% NaCl electrolyte at current densities of 40–120 mA/cm². The influence of a small addition of sulfosalicylic acid into the electrolyte on the discharge performance of the anode alloy was studied as well. The estimated values of the energy characteristics of the 0.5 kW Mg–air battery were compared with those of an Al–air battery with an alkaline electrolyte.

The stability of double-layer supercapacitors with organic electrolyte and electrodes of activated charcoal is improved by optimizing the activation parameters of the material and also by its...

Two methods (spraying and calendering) for fabrication of supercapacitor electrodes are considered. Results of tests of double-layer capacitors with aqueous (sulfuric acid) and organic (tetraethylammonium tetrafluoroborate dissolved in acetonitrile) electrolytes and electrodes fabricated from activated carbon are presented. It is shown that, depending on the type of the electrolyte, it is necessary to use different methods for fabrication of carbon electrodes.