As an emerging alternative legacy perfluoroalkyl substance, C6/C6 PFPiA (perfluoroalkyl phosphinic acids) has been detected in aquatic environments and causes potential risks to human health. The degradation mechanisms of C6/C6 PFPiA in a dielectric barrier discharge (DBD) plasma system were explored using validated experimental data and density functional theory (DFT) calculations. Approximately 94.5% of C6/C6 PFPiA was degraded by plasma treatment within 15 min at 18 kV. A relatively higher discharge voltage and alkaline conditions favored its degradation. C6/C6 PFPiA degradation was attributed to attacks of •OH, •O₂⁻, and ¹O₂. Besides PFHxPA and C2 −C6 shorter-chain perfluorocarboxylic acids, several other major intermediates including C4/C6 PFPiA, C4/C4 PFPiA, and C3/C3 PFPiA were identified. According to DFT calculations, the potential energy surface was proposed for possible reactions during C6/C6 PFPiA degradation in the discharge plasma system. Integrating the identified intermediates and DFT results, C6/C6 PFPiA degradation was deduced to occur by stepwise losing CF₂, free radical polymerization, and C-C bond cleavage. Furthermore, the DBD plasma treatment process decreased the toxicity of C6/C6 PFPiA to some extent. This study provides a comprehensive understanding of C6/C6 PFPiA degradation by plasma advanced oxidation.

作为一种新兴的替代传统全氟烷基物质，C6/C6 PFPiA（全氟烷基次膦酸）已在水生环境中检测到，并对人类健康造成潜在风险。使用经过验证的实验数据和密度泛函理论 (DFT) 计算探索了 C6/C6 PFPiA 在介质阻挡放电 (DBD) 等离子体系统中的降解机制。大约 94.5% 的 C6/C6 PFPiA 在 18 kV 的 15 分钟内被等离子体处理降解。相对较高的放电电压和碱性条件有利于其降解。C6/C6 PFPiA 降解归因于 •OH、 •O ₂ ^-和¹ O _2的攻击. 除了 PFHxPA 和 C2 -C6 短链全氟羧酸外，还鉴定了其他几种主要中间体，包括 C4/C6 PFPiA、C4/C4 PFPiA 和 C3/C3 PFPiA。根据 DFT 计算，提出了在放电等离子体系统中 C6/C6 PFPiA 降解过程中可能发生的反应的势能面。综合鉴定的中间体和DFT结果，推断C6/C6 PFPiA降解是通过逐步失去CF ₂、自由基聚合和CC键断裂而发生的。此外，DBD等离子处理工艺在一定程度上降低了C6/C6 PFPiA的毒性。本研究全面了解等离子体高级氧化对 C6/C6 PFPiA 的降解。