Sustainable H2 generation from cotton-based sportswear waste using catalytic pyrolysis with NiO supported on its own released char.

The thermochemical recycling of complex waste, such as textiles, is an attractive alternative for valorization that prevents their landfilling. This work presents a comparative study of the pyrolysis behavior of cotton and cotton-elastane blends, assessing the effect of temperature on the release of valuable fractions. The temperature rise reduced the oil yield. In the case of cotton, the temperature promoted the formation of heavier oils, while in the case of the cotton-elastane blend, the oils were lighter. These oils were composed of sugar derivatives such as d-allose, and in the case of elastane, the presence of 4-pyridinol was detected. The solid char residue displayed interesting textural properties for further valorization as microporous support, i.e., a surface area up to 500 m2 g-1. In this sense, aimed at the maximization of H2-enriched pyrolytic syngas, NiO-char catalytic formulas were prepared from the chars obtained during the pyrolysis of the two feedstocks. 5% of Ni was dispersed on the microporous material, as observed by microscopy characterization, and NiO presence is evidenced btoy X-ray photoelectron spectroscopy. Then, an ex-situ catalytic pyrolysis of both feedstocks, cotton and elastane-cotton blend, was evaluated using the mentioned NiO/char. Hence, in the case of cotton, the production of H2 was improved from 48 (non-catalytic) to 80 mmol H2 g-1 (catalytic), and in the case of cotton-elastane feedstock, from 56 (non-catalytic) to 75 mmol H2 g-1 (catalytic).