Miniaturized Near-Infrared (MicroNIR) Spectrometer in Plastic Waste Sorting.
Monika RaniClaudio MarchesiStefania FedericiGianluca RovelliIvano AlessandriIrene VassaliniSerena DucoliLaura BorgeseAnnalisa ZaccoFabjola BiloElza BontempiLaura E DeperoPublished in: Materials (Basel, Switzerland) (2019)
Valorisation of the urban plastic waste in high-quality recyclates is an imperative challenge in the new paradigm of the circular economy. In this scenario, a key role in the improvement of the recycling process is exerted by the optimization of waste sorting. In spite of the enormous developments achieved in the field of automated sorting systems, the quest for the reduction of cross-contamination of incompatible polymers as well as a rapid and punctual sorting of the unmatched polymers has not been sufficiently developed. In this paper, we demonstrate that a miniaturized handheld near-infrared (NIR) spectrometer can be used to successfully fingerprint and classify different plastic polymers. The investigated urban plastic waste comprised polyethylene (PE), polypropylene (PP), poly(vinyl chloride) (PVC), poly(ethylene terephthalate) (PET), and poly(styrene) (PS), collected directly in a recycling plastic waste plant, without any kind of sample washing or treatment. The application of unsupervised and supervised chemometric tools such as principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) on the NIR dataset resulted in a complete classification of the polymer classes. In addition, several kinds of PET (clear, blue, coloured, opaque, and boxes) were correctly classified as PET class, and PE samples with different branching degrees were properly separated.
Keyphrases
- heavy metals
- machine learning
- sewage sludge
- municipal solid waste
- pet ct
- life cycle
- computed tomography
- positron emission tomography
- high resolution
- deep learning
- photodynamic therapy
- risk assessment
- pet imaging
- fluorescence imaging
- mass spectrometry
- quantum dots
- single molecule
- loop mediated isothermal amplification