Avaluació d'alternatives industrials per a l'obtenció de nous materials que valoritzen residus queratínics
The worldwide poultry industry generates a large amount of wastes which, accordingly to the current law, are mostly discarded. These wastes include chicken feathers, keratin structures which 109.056.179 ton were generated in 2017 around the world. Taking into account this massive production and also...
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| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2019 |
| País: | España |
| Institución: | CBUC, CESCA |
| Repositorio: | TDR. Tesis Doctorales en Red |
| OAI Identifier: | oai:www.tdx.cat:10803/668087 |
| Acceso en línea: | http://hdl.handle.net/10803/668087 https://dx.doi.org/10.5821/dissertation-2117-173618 |
| Access Level: | acceso abierto |
| Palabra clave: | Àrees temàtiques de la UPC::Enginyeria química 66 |
| Sumario: | The worldwide poultry industry generates a large amount of wastes which, accordingly to the current law, are mostly discarded. These wastes include chicken feathers, keratin structures which 109.056.179 ton were generated in 2017 around the world. Taking into account this massive production and also their chemical and physical properties, keratin fibers that come from chicken feathers (CFs) are regarded as a potentially interesting material for its valorization in various areas. This option would make CFs an ecologic alternative (implying circular economy and biodegradability) to products that are already sold nowadays. Due to the increasing demand of sustainable plastic products, the use of CFs as a reinforcement of composite materials with low density polyethylene (LDPE) and polypropylene (PP) matrixes is regarded. Specifically, this work is focused on the fabrication process optimization, enhancing the compatibility between the matrix and the reinforcement. In order to achieve this objective, two strategies are followed: first, by the chemical modification of the chicken feathers by either acetylation or silanization and, secondly, by the addition of adhesion promoters like maleated polyethylene (MAPE) and maleated polypropylene (MAPP). The tests on the physical properties of the composites show that the addition of 20 % of CFs to the thermoplastic matrix decreases the tensile strength associated to a weak interfacial adhesion as it was demonstrated by scanning electron microscopy. However, when the MAPE/MAPP is added to the mixture, a significant increase in the tensile strength was noticed. On the contrary, acetylation and silane treatments did not result in any practical improvement of the properties of the biocomposites. On the other hand, nonwoven fabrics using CFs are made for acoustic insulation purposes. It is demonstrated that it is possible to fabricate a material with 50 % CFs and 50 % wool (W), with similar acoustic properties to those of a conventional insulation material such as stone wool (SW), even behaving better for frequencies below 2200 Hz. Life cycle assessment (LCA) studies show that the environmental impacts decrease when the amount of CFs increases in those nonwoven materials containing CFs and W, except for abiotic depletion and eutrophication impact categories. However, SW only present worse environmental performance than the CFs based nonwoven fabrics for few impact categories due to the negative contribution caused by the impacts associated to the W processing. Finally, the sorption of Cu2+ using CFs is studied and the results were compared with those obtained for commercial bentonite (BNT). The study of sorption kinetics at pH 4 show that, for low concentrations of Cu2+ (0,2 mM), sorption is greater and faster for CFs (94 %) rather than for BNT (67 %). Nevertheless, at higher metal concentrations (6 mM), BNT show a higher sorption capacity (87 %) than CFs (15 %). Similar results are obtained using CFs in real industrial wastewater. The material characterization by means of infrared spectroscopy and thermogravimetry techniques, before and after its use, shows that there are no significant changes in the structure of the sorbent, which would allow their reuse. |
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