中国科学技术大学康彦彪团队报道了PFASs的光催化低温除氟。相关研究成果发表在2024年11月20日出版的国际知名学术期刊《自然》。

多氟烷基和全氟烷基物质（PFASs）存在于许多日常消费品中，通常是因为它们具有较高的热稳定性和化学稳定性，以及疏水性和疏油性。

然而，赋予PFASs特性的惰性碳-氟（C-F）键也通过脱氟提供了抗分解性，导致其在环境和人体中长期存在，引发了大量的安全和健康问题。

尽管最近在销毁官能化PFASs的非焚烧方法方面取得了进展，但全氟化碳（PFCs）以及聚四氟乙烯（PTFE）等聚合物PFASs的回收工艺，仅限于使用高温或强还原剂的方法。

该文中，研究人员报告了用高度扭曲的咔唑核超光还原剂KQGZ，对PFASs进行脱氟。一系列PFASs可以在40-60°C下进行光催化脱氟。PTFE的主要产物是无定形碳和氟化物盐。

低聚全氟辛烷磺酸（PFCs）、全氟辛基磺酸（PFOS）、多氟辛酸（PFOA）及其衍生物等PFASs会产生碳酸盐、甲酸盐、草酸盐和三氟乙酸盐作为脱氟产物。这使得PFASs中的氟可以作为无机氟化物盐回收。

机理研究揭示了PTFE和低聚PFASs的反应行为和产物成分的差异。

该项工作为“永久性化学物质”PFASs的低温光还原脱氟打开了一扇窗户，特别是对于PTFE，以及新的超级光还原剂的发现。

附：英文原文

Title: Photocatalytic low-temperature defluorination of PFASs

Author: Zhang, Hao, Chen, Jin-Xiang, Qu, Jian-Ping, Kang, Yan-Biao

Issue&Volume: 2024-11-20

Abstract: Polyfluoroalkyl and perfluoroalkyl substances (PFASs) are found in many everyday consumer products, often because of their high thermal and chemical stabilities, as well as their hydrophobic and oleophobic properties1. However, the inert carbon–fluorine (C–F) bonds that give PFASs their properties also provide resistance to decomposition through defluorination, leading to long-term persistence in the environment, as well as in the human body, raising substantial safety and health concerns1,2,3,4,5. Despite recent advances in non-incineration approaches for the destruction of functionalized PFASs, processes for the recycling of perfluorocarbons (PFCs) as well as polymeric PFASs such as polytetrafluoroethylene (PTFE) are limited to methods that use either elevated temperatures or strong reducing reagents. Here we report the defluorination of PFASs with a highly twisted carbazole-cored super-photoreductant KQGZ. A series of PFASs could be defluorinated photocatalytically at 40–60°C. PTFE gave amorphous carbon and fluoride salts as the major products. Oligomeric PFASs such as PFCs, perfluorooctane sulfonic acid (PFOS), polyfluorooctanoic acid (PFOA) and derivatives give carbonate, formate, oxalate and trifluoroacetate as the defluorinated products. This allows for the recycling of fluorine in PFASs as inorganic fluoride salt. The mechanistic investigation reveals the difference in reaction behaviour and product components for PTFE and oligomeric PFASs. This work opens a window for the low-temperature photoreductive defluorination of the ‘forever chemicals’ PFASs, especially for PTFE, as well as the discovery of new super-photoreductants.

DOI: 10.1038/s41586-024-08179-1

Source: https://www.nature.com/articles/s41586-024-08179-1