Feng Zhao, Jingzhi Yao*, Xinyu Liu, Man Deng, Xiaojia Chen, Changzhi Shi, Lei Yao, Xiaofei Wang and Mingliang Fang*,
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引用次数: 0
Abstract
N,N′-Substituted p-phenylenediamines (PPDs) are widely utilized as rubber antioxidants and emitted into the environment with their transformation products (TPs) including the highly toxic 6PPD-quinone. However, the occurrence of PPDs and TPs in inconspicuous rubber products and their oxidation kinetics under natural aging conditions remains unclear. Herein, we performed a field survey of these compounds in crumb rubbers from 40 school artificial turfs. Twelve PPDs and TPs were frequently detected in rubber particles, dominated by the well-known N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine (6PPD) and N-isopropyl-N′-phenyl-1,4-phenylenediamine (IPPD), as well as their PPD-Qs. One pristine rubber material was chosen to simulate the aging process and examine the oxidation kinetics. The concentrations of all antioxidants in rubber powder decreased > 50% within 4 days under natural aging, much faster than that in particles, suggesting the size effect on oxidation. Different PPDs had distinct oxidation degrees under both field and simulated experiments. Besides ozone, we found that high temperature could induce a significantly faster decay of PPDs within rubber particles than UV exposure. In sum, our field and simulated investigations reveal that the transformation of PPDs to PPD-Qs is ubiquitous and chemically specific in artificial turf, which could be affected by particle size and temperature as key factors in controlling oxidation kinetics.
期刊介绍:
Environmental Science & Technology Letters serves as an international forum for brief communications on experimental or theoretical results of exceptional timeliness in all aspects of environmental science, both pure and applied. Published as soon as accepted, these communications are summarized in monthly issues. Additionally, the journal features short reviews on emerging topics in environmental science and technology.