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Journal ArticleDOI

A hybrid LIBS–Raman system combined with chemometrics: an efficient tool for plastic identification and sorting

20 Mar 2017-Analytical and Bioanalytical Chemistry (Springer Berlin Heidelberg)-Vol. 409, Iss: 13, pp 3299-3308
TL;DR: The efficacy of a combined laser-induced breakdown spectroscopy (LIBS)–Raman system for the rapid identification and classification of post-consumer plastics is demonstrated and the potential limitations of any of these techniques for sample identification can be overcome by the complementarity of these two techniques.
Abstract: Classification of plastics is of great importance in the recycling industry as the littering of plastic wastes increases day by day as a result of its extensive use. In this paper, we demonstrate the efficacy of a combined laser-induced breakdown spectroscopy (LIBS)–Raman system for the rapid identification and classification of post-consumer plastics. The atomic information and molecular information of polyethylene terephthalate, polyethylene, polypropylene, and polystyrene were studied using plasma emission spectra and scattered signal obtained in the LIBS and Raman technique, respectively. The collected spectral features of the samples were analyzed using statistical tools (principal component analysis, Mahalanobis distance) to categorize the plastics. The analyses of the data clearly show that elemental information and molecular information obtained from these techniques are efficient for classification of plastics. In addition, the molecular information collected via Raman spectroscopy exhibits clearly distinct features for the transparent plastics (100% discrimination), whereas the LIBS technique shows better spectral feature differences for the colored samples. The study shows that the information obtained from these complementary techniques allows the complete classification of the plastic samples, irrespective of the color or additives. This work further throws some light on the fact that the potential limitations of any of these techniques for sample identification can be overcome by the complementarity of these two techniques.
Citations
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Journal ArticleDOI
TL;DR: In this paper, the broad capability of laser-induced breakdown spectroscopy (LIBS) for in situ elemental profiling and mapping of metals in biological materials such as plant, animal and human specimens is discussed.

105 citations

Journal ArticleDOI
TL;DR: In this article, a review of legacy additives in plastic waste streams, their end-of-life treatment options related to legislation covering these additives and links between regulation and waste management is presented.
Abstract: Plastics are widely used because of their diverse mechanical and physicochemical properties, however, many plastic products can only achieve their specific characteristics if mixed with additives, like flame retardants, stabilizers, and plasticizers. Some of the formerly used plastic additives, however, are in the meantime evaluated as substances of very high concern (SVHC) or even persistent organic pollutants (POP) and are referred to as “legacy additives”. Therefore, the improper disposal of legacy plastic waste as well as the recycling and reuse of such can lead to continuous circulation of harmful additives into the environment, threatening plant and animal life, and human health. The environmental threats posed by hazardous additives have been addressed by international regulations like the Registration, Evaluation, and Authorization of Chemicals (REACH) regulation and the Stockholm Convention. They set thresholds for hazardous chemicals including some legacy additives, which regulate trading and waste management, and aim at a fast phase out of hazardous compounds. At the same time, governmental, non-governmental and industrial players support a circular economy of goods including plastics, which resulted and will further result in increasing recycling quotas for waste plastics. When it comes to plastics containing legacy additives a conflict of objectives may arise, namely saving polymeric resources versus phase-out of hazardous compounds. This review paper discusses legacy additives in plastic waste streams, their end-of-life treatment options related to legislation covering these additives and links between regulation and waste management.

102 citations

Journal ArticleDOI
TL;DR: In the last few years, LIBS has become an established technique for the assessment of elemental concentrations in various sample types as discussed by the authors, since this technique allows to associate the obtained elemental composition information with the spatial coordinates of the investigated sample.

69 citations

Journal ArticleDOI
TL;DR: A review of recent developments in applications of atomic spectrometry to the characterisation of metals, chemicals and materials can be found in this paper, where the authors identify research trends solely from an annual review of the literature and a certain perspective can be obtained from examining the developments described in recent years in this ASU review series.
Abstract: This ASU review focuses on developments in applications of atomic spectrometry to the characterisation of metals, chemicals and materials. It is difficult to identify research trends solely from an annual review of the literature, but a certain perspective can be obtained from examining the developments described in recent years in this ASU review series. It is, for example, evident that there has been a decline in truly novel applications for the analysis of chemicals, perhaps indicative of the fact that, for most sample types, there is now an abundance of methods available in the literature. Those papers that have appeared in the year under review have either focused on specific problems not yet fully addressed (e.g. determination of Si in gasoline) or on incremental development of well-established approaches to sample preparation or measurement. Nevertheless, there has been a very noticeable increase in activity in relation to publication of methods for the characterisation of pharmaceuticals. This is directly linked to changes in the US Pharmacopeia requirements for registration of pharmaceuticals for human use that require assessments to be made for trace element content. Laser-induced breakdown spectrometry is becoming widely employed for applications involving the characterisation of a wide variety of metals, materials and other solid sample types. Efforts are being made to overcome the perceived weaknesses of the technique, such as lack of sensitivity, elemental fractionation, accuracy and/or precision. Advances have been made, for example, using dual-pulse lasers to improve sensitivity, or by employing chemometrics methods with full spectrum data to improve the robustness of calibration. Many of these reported LIBS developments draw from, and have relevance for, applications involving LA-ICP-MS, which continues to be a popular means of generating highly sensitive lateral and depth profiling and bulk compositional information for a wide range of materials and solids. The use of field portable instrumentation for in situ analysis continues grow, with LIBS and XRF techniques amongst those most frequently cited. The development of such instrumentation has had a substantial impact in the examination of cultural heritage artefacts, especially in relation to paintings, wall murals and other objects of unique historical value. The latter area of application has also seen continued use of combinations of surface (SIMS, XPS, SEM-EDS, PIXE, GD and laser ablation methods) and bulk (ICP-OES, ICP-MS, AAS, XRF) analysis techniques to reveal details of objects that would not otherwise be identified (for example preparatory sketches hidden under original works of art or materials provenance). This trend towards using a multi-technique based approach has also been apparent in the characterisation of multi-layer or heterogeneous organic and inorganic materials and metals. Finally, methods for the analysis of nanoparticles and nanostructures have been reported, based primarily on single particle (SP)-ICP-MS and flow field flow fractionation (A4F). The investigation of methods of drift correction, the use of flow injection and isotope dilution methodologies in combination with SP-ICP-MS are indicative of the further development of this field.

55 citations

Journal ArticleDOI
Ke Liu1, Di Tian1, Chang Li1, Li Yingchao1, Guang Yang1, Yu Ding1 
TL;DR: In this article, a review of laser-induced breakdown spectroscopy (LIBS) applications for coal ranks, combustion efficiency, and environmental protection is presented, together with a description of limitations and the potential developing trend for this topic.
Abstract: With massive coal consumption in the industry, the increasing requirements for improving combustion efficiency and environmental protection raise widespread interests. Laser-induced breakdown spectroscopy (LIBS) shows the merits of high-speed, minimally destructive, simple preparation, etc. Combining it with the analytical chemistry methods have become a promising way for coal analysis. In this work, LIBS instruments for collecting coal spectra, pretreatment methods for coal samples, preprocessing of coal data, and analytical chemistry methods for coal analysis were summarized. Moreover, LIBS applications, including coal ranks, combustion efficiency, and environmental protection, are provided. Finally, this review proposes a description of limitations and the potential developing trend for this topic.

47 citations

References
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Journal ArticleDOI
TL;DR: The mechanisms of generation and potential impacts of microplastics in the ocean environment are discussed, and the increasing levels of plastic pollution of the oceans are understood, it is important to better understand the impact of microPlastic in the Ocean food web.

4,706 citations

MonographDOI
15 Jun 1989
TL;DR: The theory and practice of infrared and Raman spectroscopy as applied to the study of the physical and chemical characteristics of polymers is described in this article, which is intended to be especially suitable for use in undergraduate courses in physics, chemistry or materials science at both universities and polytechnics.
Abstract: This book describes the theory and practice of infrared and Raman spectroscopy as applied to the study of the physical and chemical characteristics of polymers. Its purpose is to give the beginning researcher in the field a firm foundation and a starting point for the study of more-advanced literature. To this end the book concentrates on the fundamentals of the theory and nomenclature, and on the discussion of well-documented illustrations of these fundamental principles, including many now-classic studies in the subject. No previous knowledge of either polymers or vibrational spectroscopy is assumed. The book will be of value to anyone beginning research on the vibrational spectroscopy of polymers, either from a physics or a chemistry background. It is intended to be especially suitable for use in undergraduate courses in physics, chemistry or materials science at both universities and polytechnics.

404 citations

BookDOI
30 Sep 2004
TL;DR: An overview of the family of polyester polymers is given in this paper, which comprises an important group of plastics that span the range of commodity polymers to engineering resins.
Abstract: Provides an overview of the family of polyester polymers which comprise an important group of plastics that span the range of commodity polymers to engineering resins. It describes the preparation, properties and applications of polyesters. Readers will also find details on polyester-based elastomers, biodegradable aliphatic polyester, liquid crystal polyesters and unsaturated polyesters for glass-reinforced composites. • Presents an overview of the most recent developments. • Explores synthesis, catalysts, processes, properties and applications. • Looks at emerging polyester materials as well as existing ones. • Written by foremost experts from both academia and industry, ensuring that both fundamentals and practical applications are covered.

381 citations

Journal ArticleDOI
TL;DR: Floating marine plastic debris was found to function as solid-phase extraction media, adsorbing and concentrating pollutants out of the water column and the types of PCBs and PAHs found were similar to those found in marine sediments.
Abstract: Floating marine plastic debris was found to function as solid-phase extraction media, adsorbing and concentrating pollutants out of the water column. Plastic debris was collected in the North Pacific Gyre, extracted, and analyzed for 36 individual PCB congeners, 17 organochlorine pesticides, and 16 EPA priority PAHs. Over 50% contained PCBs, 40% contained pesticides, and nearly 80% contained PAHs. The PAHs included 2, 3 and 4 ring congeners. The PCBs were primarily CB-11, 28, 44, 52, 66, and 101. The pesticides detected were primarily p,p-DDTs and its metabolite, o,p-DDD, as well as BHC (a,b,g and d). The concentrations of pollutants found ranged from a few ppb to thousands of ppb. The types of PCBs and PAHs found were similar to those found in marine sediments. However, these plastic particles were mostly polyethylene which is resistant to degradation and although functioning similarly to sediments in accumulating pollutants, these had remained on or near the ocean surface. Particles collected included intact plastic items as well as many pieces less than 5 mm in size.

276 citations


"A hybrid LIBS–Raman system combined..." refers background in this paper

  • ...affect the identification by vibrational spectroscopy methods and thus may demand alternate analysis [32]....

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  • ...spectroscopy methods and thus may demand further analysis [32]....

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Journal ArticleDOI
TL;DR: In this article, laser-induced breakdown spectroscopy has been applied to polymer samples in order to investigate the possibility of using this method for the identification of different materials, such as polyethylene (HDPE), polyvinyl chloride (PVC) and polypropylene (PP).
Abstract: Laser-induced breakdown spectroscopy has been applied to polymer samples in order to investigate the possibility of using this method for the identification of different materials. The plasma emission spectra of high-density polyethylene (HDPE), low-density polyethylene (LDPE), polyvinyl chloride (PVC), polyethylene terephthalate (PET), and polypropylene (PP) have been studied. Spectral features have been measured-for example, the 725.7 nm chlorine line, the 486.13 mm H-beta line, and the 247.86 nm carbon line whose evaluation with neural networks permits identification accuracies between 90 and 100% , depending on polymer type.

197 citations