Key Laboratory of Integrated Regulation and Resources Development of Shallow Lakes of Ministry of Education, Hohai University, Nanjing 210098, China; College of Environment, Hohai University, Nanjing 210098, China.
Key Laboratory of Integrated Regulation and Resources Development of Shallow Lakes of Ministry of Education, Hohai University, Nanjing 210098, China; College of Environment, Hohai University, Nanjing 210098, China.
Sci Total Environ. 2024 Nov 15;951:175682. doi: 10.1016/j.scitotenv.2024.175682. Epub 2024 Aug 22.
The addition of active ingredients such as antibacterial agent and non-active ingredients such as plastic microspheres (MPs) in personal care products (PCPs) are the common pollutants in the aquatic environment, and their coexistence poses potential threat to the aquatic ecosystem. As a substitute for the traditional antibacterial ingredients triclosan and triclocarban, the usage of parachlormetaxylenol (PCMX) is on the rise and is widely used in PCPs. In this study, the adsorption and desorption behaviors of PCMX were investigated with two typical MPs, polyvinyl chloride (PVC) and polyethylene (PE), and the effects of different aging modes and molecular mechanisms were explored through batch experiments and density functional theory calculation. Both laboratory aging and field aging resulted in surface wrinkles of MPs, along with an increased proportion of oxygen-containing functional groups (CO, -OH). At the same aging time, the degree of laboratory aging was stronger than that of field aging, and the aging degree of PVC was greater that of PE. The aging process enhanced the adsorption capacity of MPs for PCMX. The equilibrium adsorption capacity of PVC increased from 3.713 mg/g (virgin) to 3.823 mg/g (field aging) and 3.969 mg/g (laboratory aging), while that of PE increased from 3.509 mg/g to 3.879 mg/g and 4.109 mg/g, respectively. Meanwhile, aging also resulted in an increase in the desorption capacity of PCMX from PVC and PE. Oxygen-containing functional groups in aged MPs could serve as adsorption sites for PCMX and improved the electrostatic adsorption capacity. Oxygen-containing groups generated on the surface of aged MPs formed hydrogen bonding with the phenolic hydroxyl groups of PCMX, which became the main driving force for adsorption. Our results reveal the potential impact and mechanism of aging on the adsorption of PCMX by MPs, which provides new insights for the interaction mechanism between environmental MPs and associated contaminants.
个人护理产品（PCP）中添加的活性成分（如抗菌剂）和非活性成分（如塑料微球（MPs））是水生环境中的常见污染物，它们的共存对水生生态系统构成了潜在威胁。作为传统抗菌成分三氯生和三氯卡班的替代品，对氯间二甲苯酚（PCMX）的使用正在增加，并广泛用于 PCP 中。在这项研究中，通过批量实验和密度泛函理论计算，研究了两种典型的 MPs（聚氯乙烯（PVC）和聚乙烯（PE））对 PCMX 的吸附和解吸行为，并探讨了不同老化模式和分子机制的影响。实验室老化和现场老化都会导致 MPs 表面出现皱纹，并增加含氧官能团（CO，-OH）的比例。在相同的老化时间内，实验室老化的程度强于现场老化，且 PVC 的老化程度大于 PE。老化过程增强了 MPs 对 PCMX 的吸附能力。PVC 的平衡吸附容量从 3.713mg/g（原始）增加到 3.823mg/g（现场老化）和 3.969mg/g（实验室老化），而 PE 的平衡吸附容量从 3.509mg/g 增加到 3.879mg/g 和 4.109mg/g。同时，老化也导致 PCMX 从 PVC 和 PE 上的解吸容量增加。老化后的 MPs 中的含氧官能团可以作为 PCMX 的吸附位点，并提高静电吸附能力。老化后 MPs 表面生成的含氧基团与 PCMX 的酚羟基形成氢键，成为吸附的主要驱动力。我们的结果揭示了老化对 MPs 吸附 PCMX 的潜在影响和机制，为环境 MPs 与相关污染物之间的相互作用机制提供了新的见解。
