Waste scrap tyres were thermally decomposed at the temperature of 600 °C and heating rate of 10 °C·min⁻¹. Decomposition was followed by the TG analysis. The resulting pyrolytic carbon black was chemically activated by a KOH solution at 800 °C. Activated and non-activated carbon black were investigated using high pressure thermogravimetry, where adsorption isotherms of N₂, CO₂, and cyclohexane were determined. Isotherms were determined over a wide range of pressure, 0.03–4.5 MPa for N₂ and 0.03–2 MPa for CO₂. In non-activated carbon black, for the same pressure and temperature, a five times greater gas uptake of CO₂ than N₂ was determined. Contrary to non-activated carbon black, activated carbon black showed improved textural properties with a well-developed irregular mesoporous-macroporous structure with a significant amount of micropores. The sorption capacity of pyrolytic carbon black was also increased by activation. The uptake of CO₂ was three times and for cyclohexane ten times higher in activated carbon black than in the non-activated one. Specific surface areas evaluated from linearized forms of Langmuir isotherm and the BET isotherm revealed that for both methods, the values are comparable for non-activated carbon black measured by CO₂ and for activated carbon black measured by cyclohexane. It was found out that the N₂ sorption capacity of carbon black depends only on its specific surface area size, contrary to CO₂ sorption capacity, which is affected by both the size of specific surface area and the nature of carbon black.

Chicken cartilage was used for the first time as a raw material for the microwave-assisted synthesis of biochar and activated carbon. Various microwave absorbers, i.e., commercial active carbon, scrap tyres, silicon carbide, and chicken bone-derived biochar, as well as various microwave powers, were tested for their effect on the rate of pyrolysis and the type of products formed. Biochars synthesised under 400 W in the presence of scrap tyres and chicken bone-derived biochar were activated with KOH and K₂CO₃ with detergent to produce activated carbon with a highly developed porous structure that would be able to effectively adsorb xylene vapours. All carbons were thoroughly characterised (infrared spectroscopy, X-ray fluorescence spectrometry, nitrogen adsorption/desorption, Raman spectroscopy, proximate and ultimate analysis) and tested as xylene sorbents in dynamic systems. It was found that the activation causes an increase of up to 1042 m²·g⁻¹ in the specific surface area, which ensures the sorption capacity of xylene about 300 mg·g⁻¹. Studies of the composition of biogas emitted during pyrolysis revealed that particularly valuable gaseous products are formed when pyrolysis is carried out in the presence of silicon carbide as a microwave absorber.

Beef and pork waste bones, both original and activated, were microwave pyrolyzed to obtain chars usable as adsorbents of xylene from air. Bone activation with potassium carbonate or potassium hydroxide has been tested to increase adsorption efficiency by inducing micropore formation and increasing surface area. Composition and structure of the resulting chars were analyzed by a wide range of methods: proximate and elemental analyses, thermogravimetry, nitrogen physisorption, X-ray fluorescence spectroscopy, Raman spectroscopy, and Fourier-transform infrared spectroscopy. The results demonstrate that the well-developed porous structure including micropores positively affects the adsorption of xylene. Beef and pork waste bones activated with potassium carbonate were proved to be a useful input material for the preparation of cheap and sustainable adsorbents of xylene from air.

This study examines the production of char from waste animal bones via pyrolysis, and assesses their chemical and structural properties in relation to their capacity for absorbing volatile organic compounds (VOC). The type of raw input material has a greater impact on the yield of pyrolysis than the process conditions of the pyrolysis process. VOC adsorption capacity is influenced by porous structure, solid carbon content and the presence of calcium.