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New Indole Derivative Heterogeneous System for the Synergistic Reduction and Oxidation of Various Per-/Polyfluoroalkyl Substances: Insights into the Degradation/Defluorination Mechanism
Environmental Science & Technology ( IF 10.8 ) Pub Date : 2023-12-06 , DOI: 10.1021/acs.est.3c05940
Zhe Wang 1 , Xin Jin 1, 2 , Ran Hong 3 , Xinhao Wang 1 , Zhanghao Chen 1 , Guandao Gao 1 , Huan He 2 , Jinyong Liu 4 , Cheng Gu 1
Affiliation  

The hydrated electron (eaq) system is typically suitable for degrading perfluoroalkyl substances (PFASs). To enhance eaq utilization, we synthesized a new indole compound (DIHA) that forms stable nanospheres (100–200 nm) in water via a supramolecular assembly. Herein, the DIHA nanoemulsion system exhibits high degradation efficiencies toward a broad category of PFASs, regardless of the headgroup, chain length, and branching structure, under UV (254 nm) irradiation. The strong adsorption of PFAS on the DIHA surface ensures its effective degradation/defluorination. Quenching experiments further demonstrated that the reaction took place on the surface of DIHA nanospheres. This specific heterogeneous surface reaction unveiled novel PFAS degradation and defluorination mechanisms that differ from previously reported eaq systems. First, the photogenerated surface electrons nonselectively attacked multiple C–F bonds of the −CF2- chain. This plays a dominant degrading/defluorinating role in the DIHA system. Second, abundant hydroxyl radicals (OH) were also produced, leading to synergistic reduction (by surface electron) and oxidation (by surface OH) in a single system. This facilitates faster and deeper defluorination of different structured PFASs through multiple pathways. The new mechanism inspires the design of innovative organo-heterogeneous eaq systems possessing synergistic reduction and oxidation functions, thereby making them potentially effective for treating PFAS-contaminated water.

中文翻译:


用于协同还原和氧化各种全氟/多氟烷基物质的新型吲哚衍生物多相体系:深入了解降解/脱氟机制



水合电子 (e aq ) 系统通常适用于降解全氟烷基物质 (PFAS)。为了提高水利用率,我们合成了一种新的吲哚化合物(DIHA),它通过超分子组装在水中形成稳定的纳米球(100-200 nm)。在此,DIHA 纳米乳液系统在 UV(254 nm)照射下对多种 PFAS 表现出高降解效率,无论头基、链长和支化结构如何。 PFAS在DIHA表面的强吸附性保证了其有效降解/脱氟。淬火实验进一步证明反应发生在DIHA纳米球的表面。这种特定的异质表面反应揭示了与之前报道的 e aq系统不同的新型 PFAS 降解和脱氟机制。首先,光生表面电子无选择性地攻击-CF 2 -链的多个C-F键。这在 DIHA 系统中起着主要的降解/脱氟作用。其次,还产生了丰富的羟基自由基( · OH),导致在单一系统中协同还原(通过表面电子)和氧化(通过表面· OH)。这有助于通过多种途径更快、更深入地对不同结构的 PFAS 进行脱氟。新机制激发了创新有机多相e aq系统的设计该系统具有协同还原和氧化功能,从而使其能够有效地处理PFAS污染的水。
更新日期:2023-12-06
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