Chemical Engineering Department, University of Alicante, San Vicente del Raspeig Road, s/n, 03690 San Vicente del Raspeig, Alicante, Spain.
Friedrich-Alexander-Universität Erlangen-Nürnberg, Chair of Aroma and Smell Research, Department of Chemistry and Pharmacy, Henkestraße 9, 91054 Erlangen, Germany; Fraunhofer Institute for Process Engineering and Packaging IVV, Giggenhauser Straße 35, 85354 Freising, Germany.
Waste Manag. 2020 Mar 1;104:228-238. doi: 10.1016/j.wasman.2020.01.021. Epub 2020 Jan 24.
The establishment of recycling systems aiming at high-quality recyclates from post-consumer plastic waste are essential to avoid the waste of resources. One main impediment for introducing recyclates into the market is their unwanted odor. For this reason, this study aimed at determining if the collection strategy affects the odor profile of post-consumer LDPE bags. Furthermore, the effect of hot water washing, inspired by the conventional mechanical recycling procedure, on the odor of post-consumer LDPE bags was screened. More than 60 odorants were detected in LDPE bags collected in a separate plastic fraction as well as in LDPE bags from the non-separated collection by means of gas chromatography-olfactometry, and 37 of them were unequivocally identified using two-dimensional gas chromatography-mass spectrometry/olfactometry. The sensory results revealed that the type of collection affects the overall odor intensity, the hedonic tone of the odor and the odor profile. Namely, cheesy and fecal smelling odorants were predominant in the waste that had not been separated at source, whereas odorants with earthy and moldy smells showed mostly higher intensity ratings in the waste separated at source. Short chain carboxylic acids, likely originating from microbial spoilage of organic waste, were found with higher dilution factors in the mixed fraction, and could, accordingly, contribute to the observed differences. Additionally, we could show that the hot washing procedure, applied to the LDPE sample from the separate collection system, significantly reduced the overall odor intensity from 8 to 6.3 (0-10 scale). However, the washed waste still showed high smell intensity ratings.
建立旨在从消费后塑料废物中获得高质量再生料的回收系统对于避免资源浪费至关重要。将再生料引入市场的一个主要障碍是其令人不快的气味。出于这个原因，本研究旨在确定收集策略是否会影响消费后 LDPE 袋的气味特征。此外，还研究了受传统机械回收过程启发的热水清洗对消费后 LDPE 袋气味的影响。通过气相色谱-嗅觉测量法，在单独的塑料部分收集的 LDPE 袋以及在非分离收集中收集的 LDPE 袋中检测到超过 60 种气味物质，其中 37 种通过二维气相色谱-质谱/嗅觉测量法被明确识别。感官结果表明，收集方式会影响整体气味强度、气味愉悦程度和气味特征。具体来说，在未进行源头分离的废物中，存在奶酪和粪便气味的气味物质占主导地位，而在源头分离的废物中，具有泥土和发霉气味的气味物质则表现出更高的强度等级。短链羧酸可能来源于有机废物的微生物腐败，在混合部分中发现具有更高的稀释因子，因此可能导致观察到的差异。此外，我们还表明，应用于单独收集系统的 LDPE 样品的热水清洗程序可将整体气味强度从 8 降低到 6.3（0-10 级）。然而，清洗后的废物仍表现出高气味强度等级。
