Potential of Pyrolysis for valuable products obtaining from wheat straw lignin produced by CIMV technology

Two configurations of fast pyrolysis realized in flowing (inert gas flow) and ablative-type reactors were used for phenolic fraction obtaining. The maximum yield of phenolic compounds was achieved at 450 degrees of Celsius in the case of ablative reactor usage (7,6%). Application of catalysts (Na+ and K+) allowed to increase the yield of phenolic compounds up to 8,5%

Wood and Black Liquor-Based N-Doped Activated Carbon for Energy Application

The research was funded by the Latvian Council of Science project “Nanostructured Nitrogenated Carbon Materials as Promoters in Energy Harvesting and Storage Technologies”, project No LZP-2018/1-0194, “New biomass origin materials hybrid carbon composites for energy storage” project No LZP-2020/2-0019 and postdoc project “Nitrogen and phosphorus-containing biomass based activated carbons for fuel cells and supercapacitors” project No 1.1.1.2/VIAA/4/20/596.Fuel cells, batteries and supercapacitors are critical to meet the rising global demand for clean, sustainable energy. Biomass-derived activated carbon can be obtained with tailored properties to fulfil the extensive need for low-cost, high-performance, catalyst and electrode materials. To investigate the possibility of nanoporous nitrogen-doped carbon materials as catalysts in fuel cells and electrodes in lithium-ion batteries, biomass precursors were thermochemically activated with NaOH at 800 °C, nitrogen was introduced using dicyandiamide and doping was performed at 800 °C. The chemical composition, porous structure, texture and electrochemical properties of the obtained materials change depending on the biomass precursor used. It has been found that the most promising precursor of the obtained materials is wood char, both as an oxygen reduction catalyst in fuel cells, which shows better properties than the commercial 20% Pt/C catalyst, and as an anode material in Li-ion batteries. However, catalysts based on black liquor and hybrid material have comparable properties with commercial 20% Pt/C catalyst and can be considered as a cheaper alternative. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Latvian Council of Science LZP-2018/1-0194, LZP-2020/2-0019; postdoc project 1.1.1.2/VIAA/4/20/596; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART2

Effect of Pretreatment on the Nitrogen Doped Activated Carbon Materials Activity towards Oxygen Reduction Reaction

Nitrogen-doped activated carbons with controlled micro- and mesoporosity were obtained from wood and wastes via chemical processing using pre-treatment (pyrolysis at 500 °C and hydrothermally carbonization at 250 °C) and evaluated as oxygen reduction catalysts for further application in fuel cells. The elemental and chemical composition, structure and porosity, and types of nitrogen bonds of obtained catalyst materials were studied. The catalytic activity was evaluated in an alkaline medium using the rotating disk electrode method. It was shown that an increase in the volume of mesopores in the porous structure of a carbon catalyst promotes the diffusion of reagents and the reactions proceed more efficiently. The competitiveness of the obtained carbon materials compared to Pt/C for the reaction of catalytic oxygen reduction is shown.publishedVersio

Products of Fast Pyrolysis of Wood, Their Properties and Applicability

Bio-oils of different hardwood species were obtained in a 2-stage ablative pyrolysis reactor. The GC/MS analysis of the bio-oils has shown a different content of products of degradation of carbohydrates and lignin depending on the wood species. Bio-oils were dispersed in water and separated to soluble (Py-C) and insoluble (Py-L) fractions. The fractions were characterised by the Py-GC/MS method. It is shown that the Py-C fraction contains, besides products of carbohydrate origin, phenolic products, which are represented mainly by syringyl derivatives. The antioxidant properties of Py-L and Py-C isolated from bio-oil of different wood species were characterised using three assays such as ABTS●+/ DPPH●/superoxide radical scavenging

Hydrothermal Carbonization vs. Pyrolysis: Effect on the Porosity of the Activated Carbon Materials

Porous carbon materials (specific area over 2400 m2 g−1) were obtained from birch wood chips, the waste of its thermochemical processing water-insoluble lignocellulosic pyrolysis tar, and their mixture, by thermochemical activation with NaOH at 800 °C. Raw materials were carbonized by two methods: pyrolysis (500 °C) and hydrothermal (250 °C) treatment. The elemental and chemical composition of precursors and the effect of these parameters on the obtained carbon materials’ structure and porosity were studied. Results of the study showed that the carbonization method has little effect on the activated carbons’ specific surface area values; however, it allows for the regulation of pore size distribution

Lignocelulozes atkritumproduktu parstrades termokatalitiskie procesi ar monomeru produktu un aktivo oglu iegusanu

Available from Latvian Academic Library / LAL - Latvian Academic LibrarySIGLELVLatvi

Synthesis and Application of Nanoporous Activated Carbon in Supercapacitors

Influence of the thermocatalytical synthesis on the formation of the porous structure and the properties of microporous carbon wood-based materials was shown. It was found that increase of activation temperature and addition ratio of alkali activator can be used to control not only total pore volume, but also micropore and mesopore proportion. The results of tests on the synthesized carbon materials as electrodes in supercapacitors are shown, as well as the influence of properties of the porous structure of carbon materials on working characteristics of electrodes. It was shown that the increase of activation temperature from 600 °C to 800 °C led to an increased proportion of mesopores in the porous structure; this negatively influencen the cell capacity of the supercapacitor. It was found that the most feasible way of production of activated cabons for the use as electrodes in supercapacitors with sulphuric acid-based electrolyte is low-temperature activation

Characterization of Softwood and Hardwood LignoBoost Kraft Lignins with Emphasis on their Antioxidant Activity

Fractionation of softwood and hardwood LignoBoost kraft lignins, using sequential extraction with organic solvents of increasing hydrogen-bonding ability (dichloromethane, n-propanol, and methanol), was carried out. Using SEC, analytical pyrolysis, FTIR and UV/VIS spectroscopy, and chemical analytical methods, four fractions were obtained and characterized in terms of their yield, composition, functionality, lignin structural features, and antioxidant properties. In tests with free radicals (ABTS●+, DPPH●, O2●-) and the ORAC (oxygen radical absorbance capacity) assay, the high radical scavenging capacity of the lignin’s soluble fractions was demonstrated. The antioxidant activity of the fractions was tested by their influence on thermo-oxidative destruction of model polyurethane elastomers. The TGA data clearly revealed the antioxidant effect of the three fractions, with the most prominent activity for the propanol-soluble fraction. The dichloromethane fraction has potential as an antioxidant for non-polar products. Novel correlations between lignin’s structural features and its radical scavenging activity were found that can be used for tuning lignin’s antioxidant properties

Feasibility of Processing and Utilisation of Used up Railway Sleepers

For the time being, pyrolysis of unfit used-up sleepers is a good option of pre-treatment to overcome the strict requirements of regulations on burning of sleepers. The charcoal prepared at a maximum temperature of 500 to 600oC, which practically does not contain benzo(a)pyrene and more than 0.03 to 0.05% sulphur, is a clean fuel for domestic or industrial use. Due to the creosote content in the sleeper wood, the caloricity of the pyroligneous vapour is high enough to cover not only the heat consumption of the process, but also for other uses. The process is energetically self-sufficient and environmentally friendly