PMID- 37481925 OWN - NLM STAT- PubMed-not-MEDLINE LR - 20230906 IS - 1873-3557 (Electronic) IS - 1386-1425 (Linking) VI - 302 DP - 2023 Dec 5 TI - Multi-level color classification of post-consumer plastic packaging flakes by hyperspectral imaging for optimizing the recycling process. PG - 123157 LID - S1386-1425(23)00842-9 [pii] LID - 10.1016/j.saa.2023.123157 [doi] AB - In a circular economy perspective, the development of fast and efficient sensor-based recognition strategies of plastic waste, not only by polymer but also by color, plays a crucial role for the production of high quality secondary raw materials in recycling plants. In this work, mixed colored flakes of high-density polyethylene (HDPE) from packaging waste were simultaneously classified by hyperspectral imaging working in the visible range (400-750 nm), combined with machine learning. Two classification models were built and compared: (1) Partial Least Square-Discriminant Analysis (PLS-DA) for 6 HDPE macro-color classes identification (i.e., white, blue, green, red, orange and yellow) and (2) hierarchical PLS-DA for a more accurate discrimination of the different HDPE color tones, providing as output 14 color classes. The obtained classification results were excellent for both models, with values of Recall, Specificity, Accuracy, and F-score in prediction close to 1. The proposed methodological approach can be utilized as sensor-based sorting logic in plastic recycling plants, tuning the output based on the required needs of the recycling plant, allowing to obtain a high-quality recycled HDPE of different colors, optimizing the plastic recycling process, in agreement with the principles of circular economy. CI - Copyright (c) 2023 The Authors. Published by Elsevier B.V. All rights reserved. FAU - Cucuzza, Paola AU - Cucuzza P AD - Department of Chemical Engineering, Materials & Environment, Sapienza University of Rome, Rome, Italy. FAU - Serranti, Silvia AU - Serranti S AD - Department of Chemical Engineering, Materials & Environment, Sapienza University of Rome, Rome, Italy. Electronic address: silvia.serranti@uniroma1.it. FAU - Capobianco, Giuseppe AU - Capobianco G AD - Department of Chemical Engineering, Materials & Environment, Sapienza University of Rome, Rome, Italy. FAU - Bonifazi, Giuseppe AU - Bonifazi G AD - Department of Chemical Engineering, Materials & Environment, Sapienza University of Rome, Rome, Italy. LA - eng PT - Journal Article DEP - 20230714 PL - England TA - Spectrochim Acta A Mol Biomol Spectrosc JT - Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy JID - 9602533 SB - IM OTO - NOTNLM OT - Circular economy OT - Color sorting OT - HDPE OT - Hierarchical model OT - Hyperspectral imaging OT - Machine learning OT - PLS-DA OT - Plastic waste OT - Recycling COIS- Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. EDAT- 2023/07/24 00:41 MHDA- 2023/07/24 00:42 CRDT- 2023/07/23 18:06 PHST- 2023/03/31 00:00 [received] PHST- 2023/06/25 00:00 [revised] PHST- 2023/07/13 00:00 [accepted] PHST- 2023/07/24 00:42 [medline] PHST- 2023/07/24 00:41 [pubmed] PHST- 2023/07/23 18:06 [entrez] AID - S1386-1425(23)00842-9 [pii] AID - 10.1016/j.saa.2023.123157 [doi] PST - ppublish SO - Spectrochim Acta A Mol Biomol Spectrosc. 2023 Dec 5;302:123157. doi: 10.1016/j.saa.2023.123157. Epub 2023 Jul 14.