Oral
Abstract
Research summary supplied by the authors
Many strategies have been adopted, in recent years, in order to minimize the impact of tannery waste, mainly made up of solid waste, such as sewage sludge, shavings, trimmings, splits and more. On the other hand, tanning waste recovery processes already identified are a virtuous application case of the circular bioeconomy for the use of waste tanning biomass, as secondary raw materials in the production of other industrial sectors. Currently, the main challenges are focalized on finding solutions for the transformation and valorization of tanned waste, characterized by a significant and variable chemical complexity; moreover, the growing use of innovative tanning systems, makes the search for solutions for the treatment of waste more challenging. In the present work, which originates from a Research and Development Project, co-financed by the Italian Ministry of Economic Development, the use of mechanical pre-treatments using ball milling technologies has been identified as a particularly sustainable, promising and transversal approach, for obtaining leather micro and nano-fibers, to be used as a reinforcement and replacement component in finishing, through conservative processes of the collagen structure, according to the PMW (Principle Minimal Wrecking) and PMS (principle of massive separation) principles. The obtained micro and nano-fibers have been finely characterized, by multiple techniques including X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Attenuated Total Reflection infrared spectroscopy (ATR-IR); then, water dispersions of the fibers have been used in finishing formulations, in addiction or substitution of polyurethane and polyacrylate based chemicals. The obtained films have been applied on leather samples, both on laboratorial and industrial scale. The performances of the obtained films and of the treated leather samples have been tested in terms of mechanical, chemical-physical properties, mereological features and sustainability impact, through multiple techniques, including Thermogravimetric/Derivative Thermogravimetric analysis (TG/DTG), Attenuated Total Reflection infrared spectroscopy (ATR-IR); Gas chromatography–mass spectrometry (GC-MS) - Purge & Trap equipped. Finally, the studies carried out allowed to verify the applicability of the strategy to different sectors, with reference to the production of leather for footwear, leather goods and the automotive industry, determining the impacts in terms of economic and environmental impacts, which highlighted the feasibility of the approach for obtaining finishes with increased performance, biodegradability and sustainability.