Halpern Emily, Heirty Lauren, West Christopher, Li Yitao, Kim Won M, Mennito Anthony S, Laskin Alexander
Department of Chemistry, Purdue University, West Lafayette, IN, 47907, USA.
Department of Statistics, Purdue University, West Lafayette, IN, 47907, USA.
Environ Sci Process Impacts. 2025 Jan 22;27(1):104-118. doi: 10.1039/d4em00501e.
The increasing global demand for plastic has raised the need for effective waste plastic management due to its long lifetime and resistance to environmental degradation. There is a need for rapid plastic identification to improve the mechanical waste plastic sorting process. This study presents a novel application of Temperature-Programmed Desorption-Direct Analysis in Real Time-High Resolution Mass Spectrometry (TPD-DART-HRMS) that enables rapid characterization of various plastics. This technique was applied on four commercially available reference polymers (polyethylene, polypropylene, polystyrene, polyvinyl chloride) as well as three "waste" plastic samples of mixed origin. These waste plastic samples were obtained as discards from various industrial processes with limited analytical characterization data. Through the application of CH Kendrick mass defect (KMD) grouping, characteristic trends in the mass spectra of each sample were identified, allowing for a simplified numerical comparison. This approach utilized a robust statistical approach using the Tanimoto coefficient, allowing for the quantitative measures of similarity between standards and unknown samples. The application of this mathematical evaluation methodology was used to identify plastic types and to distinguish structurally similar polymers. Additionally, we report that a chloride ion clustering effect with copper substrate can identify chlorinated polymer PVC (polyvinyl chloride) utilizing pyro-(-)DART-HRMS mode. PVC polymer is of particular interest in recycling due to its high chloride content, which can present technical challenges for some types of recycling. We found that chloride ion clusters are a good screening marker for the presence of chlorinated polymers in mixed waste plastic samples. This study can possibly help advance rapid and accurate analytical techniques for identifying the composition of waste plastics to advance the effectiveness of the waste plastic sorting process.
由于塑料使用寿命长且抗环境降解，全球对塑料需求的不断增加，使得有效管理废塑料的需求也随之上升。为了改进机械废塑料分选过程，需要快速识别塑料。本研究提出了一种程序升温脱附-实时直接分析-高分辨率质谱（TPD-DART-HRMS）的新应用，该应用能够快速表征各种塑料。该技术应用于四种市售参考聚合物（聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯）以及三个来源混合的“废”塑料样品。这些废塑料样品是从各种工业过程的废弃物中获得的，其分析表征数据有限。通过应用CH肯德里克质量亏损（KMD）分组，确定了每个样品质谱图中的特征趋势，从而实现了简化的数值比较。该方法采用了基于塔尼莫托系数的稳健统计方法，能够对标准样品和未知样品之间的相似性进行定量测量。这种数学评估方法的应用用于识别塑料类型并区分结构相似的聚合物。此外，我们报告称，在热解（-）DART-HRMS模式下，氯离子与铜底物的聚类效应可识别含氯聚合物PVC（聚氯乙烯）。由于PVC聚合物的高氯含量，其回收利用备受关注，这对某些类型的回收利用可能带来技术挑战。我们发现氯离子簇是混合废塑料样品中含氯聚合物存在的良好筛选标记。这项研究可能有助于推动快速准确的分析技术，以识别废塑料的成分，从而提高废塑料分选过程的有效性。
