Study on Possible Transformation of Leather and Textile Wastes in Carbonised Materials by Pyrolysis Under Different Gas Conditions

The possibility of using pyrolysis for the valorisation of leather and textile wastes constituting post-consumer clothes is analysed in this paper. The effect of gas type was investigated on the physico-chemical properties, composition, structure, and formation of the specific surfaces of carbonised materials produced by the pyrolysis process. The differences in the elemental composition of the carbonised materials derived from textile and leather wastes may be due to the specific chemical compositions. Both textile and leather wastes are rich in organic compounds, but their structural and compositional differences significantly influence the element content of carbonised materials. The characteristic feature of carbonised material made from leather waste is a relatively high nitrogen content (approx. 9 wt. %). In turn, in the case of carbonised material made from textile waste, a high carbon content is characteristic (75–80 wt. %). Moreover, G- and D-bands were detected in all the analysed carbonised materials. The presence of these bands confirms the transformation of leather and textile wastes into carbon materials. It was found that maintaining a high degree of order in the structure (calculated as ID/IG ratios based on the D and G peak intensities) of carbonised materials is advantageous to conducting the pyrolysis process on textile materials in N2 and on leather materials in CO2. The carbonised materials produced using these gases are characterised by an ID/IG ratio at a level of 0.05. Pyrolysis carried out in these gases also has a positive effect on the size of the BET surface area. However, it was shown that the carbonised products from textile materials are characterised by a higher BET surface area than that of carbonised products from leather materials regardless of the type of gas used during the pyrolysis process. Furthermore, all the carbonised materials are characterised by a high percentage content of mesopores in the carbon structure. These types of carbon materials have widespread application potential. The presented studies contribute data about the pyrolytic processing of post-consumer clothes (such as leather and textile waste) into carbonised materials to reuse, according to the circular economy model.