Summary of - Spectroscopy: A promising tool for plastic waste management

Document Type

Article

Abstract

Study Background: The review article presented titled “Spectroscopy: A promising tool for plastic waste management” by Dr. Adarsh U.K., Dr. Kartha V.B., Dr. Santhosh C., and Dr. Unnikrishnan V.K. focuses on the potential application of conventional and multimodal spectroscopies in the plastic characterization and sorting process. The article provides a comprehensive outlook on current plastic sorting mechanisms, development in spectroscopy-based approaches and future prospect of utilizing combined spectroscopy for the plastic characterization for sorting application.

Research Goals and Hypothesis: The goal of the review article is to review the current modalities for plastic sorting, evaluating the recent advancements in application of spectroscopic technics in overcoming the shortcomings of conventional methods, and to propose a prospective methodology for rapid and accurate classifying plastics gr recycling.

Methodological Approach:

  1. A general comparison of commonly used techniques (conventional and spectroscopy) for plastic characterization and sorting with an emphasis on limitations of conventional techniques.
  2. A comprehensive review on recent developments in application of spectroscopic techniques (Laser Induced Breakdown Spectroscopy (LIBS), Raman Spectroscopy, Near Infrared (NIR) Spectroscopy, and Laser Induced Fluorescence (LIF) Spectroscopy).
  3. Discussion on advantages and limitations of individual spectroscopy techniques
  4. Prospective on combination of spectroscopic techniques and application of the same in plastic sorting for recycling applications by utilizing constructive advantages and minimal limitations.

Results and Discoveries:

  1. Conventional plastic sorting methods suffer different limitations such as poor accuracy and sample subjectivity since most of the methods relies on physical properties of plastic types.
  2. Application of spectroscopy techniques in plastic sorting is gaining attention recently. However, most of the methods are in laboratory stage and require validation in industrial conditions
  3. Individual spectroscopy techniques also suffer in realizing a global plastic sorting system since they also possesses certain limitations. For instance, NIR and Raman spectroscopy struggle to characterize dark/black coloured plastics. The LIBS approach on the other hand fails when samples of similar elemental composition (like HDPE and LDPE) is subjected for classification. The LIF method requires the presence of fluorophores in the samples (either inherent or induced), which is not always satisfied in plastics.
  4. Combination of spectroscopy techniques that shares common optical requirements (LIBS-Raman-LIF) can be utilized to construct compact and cost-effective spectroscopy systems for plastic sorting with an improved accuracy compared to the single-method based approach.

Citation to the base paper: Adarsh U.K, Kartha VB, Santhosh C, Unnikrishnan VK (2022), Spectroscopy: A Promising Tool for Plastic Waste Management, TrAC Trends in Analytical Chemistry, 22, 116534, https://doi.org/10.1016/j.trac.2022.116534

Publication Date: 2022

Recommended Citation: Adarsh U.K, Kartha VB, Santhosh C, and Unnikrishnan VK, “Spectroscopy: A Promising Tool for Plastic Waste Management”, (2022)

Publication Date

2022

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