Data di Pubblicazione:
2021
Citazione:
Kinetic modelling of the biodegradation of polymeric materials / F. Conte, I. Rossetti, G. Ramis. ((Intervento presentato al convegno Milan Polymer Days – MIPOL2021 tenutosi a Milano nel 2021.
Abstract:
Kinetic modelling of the biodegradation of polymeric materials
Francesco Contea, Ilenia Rossettia, Gianguido Ramis b
a Dipartimento di Chimica, Università degli Studi di Milano, via C. Golgi 19, 20133, Milano, Italy
b DICCA, Università degli Studi di Genova, via all’Opera Pia 15A, 16149 Genova, Italy
francesco.conte@unimi.it
Abstract
Methods to treat kinetic data for the biodegradation of different plastic materials are comparatively discussed [1-4]. Different commercial plastic samples were tested for biodegradation under standard testing methods in different environments. The following standard procedures have been used for kinetic data collection: i) ISO14855 for aerobic biodegradation in compost; ii) ASTM D6691 for aerobic biodegradation in marine environment; iii) ISO 15985 for anaerobic digestion with high solids content and biogas production and iv) ISO 14853 for anaerobic biodegradability in aqueous medium and production of biogas.
Starting from the raw data, the conversion vs. time entries were elaborated using relatively simple kinetic models [5], such as integrated kinetic equations of zero, first and second order, through the Wilkinson model, or using a Michaelis Menten approach, which was previously reported in the literature. The results were validated against the experimental data and allowed to correctly compute the time for half degradation of the substrate and, by extrapolation, to estimate the final biodegradation time for all the materials tested. At the same time, a comparison between the rates of CO2 emission rate during aerobic degradation vs. biogas formation rate could be established.
The reprocessing of the kinetic data by means of a model of the first order was satisfactory in most cases of aerobic biodegradation. By contrast, The reprocessing of the data for test ISO 15985 by means of a model of the first order was unsuitable. Significantly better results were obtained with a Stover-Kincannon model, which, however, has highlighted for all substrates, including cellulose used as reference, the persistence of a fraction of the material not converted. The reliability of the model is confirmed by the data collected for cellulose, for which is estimated reliably the maximum biodegradable fraction. Also in the case of the tests carried out according to ISO 14853 the most appropriate model was found to be the Stover-Kincannon one, which also in this case has highlighted the lack of complete biodegradability of all the three substrates.
Conversion (%) of the three commercial samples and reference cellulose as a function of time.
Linear regression of the conversion data for the A formulate according to a first-order model. Blue diamonds were not included in the regression pertaining to the plateau region.
References
1. S. Ghatge, Y. Yang, J.H. Ahn, H.G. Hur, Appl. Biol. Chem. 2020, 63, 1.
2. S. Fontanella, S. Bonhomme, M. Koutny, L. Husarova, J.M. Brusson, J.P. Courdavault, S. Pitteri, G. Samuel, G. Pichon, J. Lemaire, Polym. Degrad. Stab. 2010, 95, 1011.
3. E. Castro-Aguirre, R. Auras, S. Selke, M. Rubino, T. Marsh, Polym. Degrad. Stab. 2017, 137, 251.
4. F. Kawai, M. Watanabe, M. Shibata, S Yokoyama, Y. Sudate, Polym. Degrad. Stab. 2002, 76, 129.
5. I. Rossetti, F. Conte, G. Ramis, Engineering, 2021, 2, 54.
Tipologia IRIS:
14 - Intervento a convegno non pubblicato
Elenco autori:
F. Conte, I. Rossetti, G. Ramis
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