基于氟氟作用的大气气相中短链全氟化合物的新型吸附材料及采样技术研究

Since perfluorooctane sulfontate and its salts were listed as new persistent organic pollutants (POPs) due to their toxicity, short-chain PFASs as have become increasingly used as substitute compounds. In consideration of high volatility and potential long range transport ability of short-chain PFASs, it is necessary to investigate the environmental behaviors, such as partition, exchange, and transport, of these short-chain PFASs in environmental media, in particular atmosphere, in order to further understand the fate and environmental processes and evaluate the ecological risks of short-chain PFASs. It remains a challenge to accurately analyze short-chain PFASs, particularly in the gaseous phase of the atmosphere, due to low concentrations and the concurrence of hydrophobicity and hydropholicity in PFASs compounds.This project will design and manufacture novel adsorbing materials for sampling of gaseous short-chain PFASs in the atmosphere based on F-F interaction theory, by synthesizing a variety of linear chain fluorous or aryl fluoride compounds and subsequently covalently attaching these compounds to the surface of glass wool silicon-hydroxyl. Experiments will be carried out to determine the adsorption/desorption efficiency of PFASs on the prepared adsorbing materials and the relevant influencing factors. The prepared fluoride materials will be incorporated into currently used samplers for sampling and analysis of short-chain PFASs in the gaseous phase of the atmosphere in typical polluted areas, to demonstrate the applicability and stability of the newly developed sampling techniques. It is expected that this project will develop a novel and useful sampling method suitable for analyzing gaseous PFASs in the atmosphere and further studying the environmental fate, transport, and transformation of PFASs in the environment in general.

随着有毒的全氟辛基磺酸及盐被列入持久性有机污染物清单，其替代产品短链全氟化合物的应用逐渐增加。考虑到短链全氟化合物具有较高的挥发性和潜在的长距离迁移能力，有必要研究这些全氟化合物在大气等环境介质中的交换分配规律，以深入理解这类化合物的环境行为和准确评估其生态风险。全氟化合物具有疏水、疏油特性，大气中含量低，现有采样方法难以准确测量大气气相中的短链全氟化合物。本项目拟利用直链全氟烷烃或氟代芳烃与全氟化合物的氟氟相互作用原理，通过在玻璃棉的硅羟基上共价修饰全氟烷烃或氟代芳烃，制备可用于大气气相中短链全氟化合物采样的新型吸附材料；开展室内模拟实验，研究多种全氟化合物在不同材料上的吸附/解吸附效率及其与材料修饰基团的相关性；进一步将该新型吸附材料整合到大气采样器中，采集典型污染区域大气样品，验证该采样技术的适用性和稳定性，并应用于全氟化合物的水气交换和气粒分配等环境行为研究。

本项目利用活化的玻璃纤维棉与含氟尾的有机物及芳香性化合物络合成吸附质材料，并结合氟氟作用和共轭作用原理，研究了空气中挥发性全氟化合物的吸附效应和挥发性芳基化合物的吸附机制。对挥发性全氟化合物的吸附研究结果表明，含不同碳链长度的氟尾对不同种类的短链氟化物具有特异性吸附，如接C4氟尾的玻璃纤维棉吸附对全氟正己基磺酰胺的吸附效果最好，接C6氟尾的玻璃纤维棉对七氟丁酸的吸附效果最好，含氟尾的玻璃纤维棉吸附效果整体上强于未接氟尾的玻璃纤维棉；全氟酸类物质相比于醇类物质更容易被含氟尾的玻璃纤维棉吸附，且含氟尾玻璃纤维棉对全氟磺酰氟类化合物的吸附效率偏低。此外，在空气中挥发性芳基化合物的吸附研究中，通过Langmuir和Freundlich模型研究了吸附热力学效应，使用quasi-first-order kinetic 和 quasi-second-order kinetic 模型研究其吸附动力学效应，研究结果显示通过分子间的共轭和堆积作用，对水杨醛的吸附存在物理吸附和化学吸附，而其他的挥发性化合物主要为物理吸附；进一步证实了修饰后的玻璃纤维棉对芳基化合物吸附效率都明显高于PUF-XAD材料。本研究揭示了含不同氟尾的玻璃纤维棉材料对挥发性全氟化合物的特异性吸附，且含芳基玻璃纤维棉材料对挥发性芳香化合物的有效吸附作用机制，为评估挥发性短链全氟化合物和挥发性芳香化合物的有效吸附了提供技术支撑和可靠的科学依据。