School of Environment and Energy, South China University of Technology, Guangzhou 510006, China.
School of Environmental Science and Engineering, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China.
Environ Int. 2019 Jun;127:5-12. doi: 10.1016/j.envint.2019.03.011. Epub 2019 Mar 16.
Nanoparticles of four noble metal doped titanium dioxide (i.e., Pd/TiO, Ag/TiO, Pt/TiO and Cu/TiO) were synthesized and investigated for their effectiveness to degrade polybrominated diphenyl ethers (PBDEs) under UV light. All the investigated noble metal additives can greatly enhance the performance of TiO to degrade 2,2',4',4'-tetrabromodiphenyl ether (BDE-47). However, the debromination pathways of BDE-47 in Ag/TiO and Cu/TiO systems are just contrary to those in Pd/TiO and Pt/TiO systems, and there was an induction period in the former systems but not in the latter systems. The hydrogenation experiment suggests a direct H-atom transfer mechanism in Pd/TiO and Pt/TiO systems, while in Ag/TiO and Cu/TiO systems, electron transfer is still the dominant mechanism. Electronic method was applied to explain why BDE-47 exhibit different debromination pathways based on different degradation mechanism. In addition, oxygen was proved to be able to capture both electrons and H atoms, and thus can greatly inhibit the degradation of PBDEs in all investigated systems. Finally, the merit and demerit of each metal doped TiO were discussed in detail, including the reactivity, stability and the generation of byproducts. We proposed our study greatly enhance our understanding on the mechanisms of PBDE degradation in various metal doped TiO systems.
合成了四种贵金属掺杂二氧化钛纳米粒子（即 Pd/TiO、Ag/TiO、Pt/TiO 和 Cu/TiO），并研究了它们在紫外光下降解多溴二苯醚（PBDEs）的有效性。所有研究的贵金属添加剂都可以极大地提高 TiO 降解 2,2',4,4'-四溴二苯醚（BDE-47）的性能。然而，Ag/TiO 和 Cu/TiO 体系中 BDE-47 的脱溴途径与 Pd/TiO 和 Pt/TiO 体系恰恰相反，在前两个体系中存在诱导期，而在后两个体系中则不存在。氢化实验表明，Pd/TiO 和 Pt/TiO 体系中存在直接 H 原子转移机制，而在 Ag/TiO 和 Cu/TiO 体系中，电子转移仍然是主要机制。电子方法被应用于解释为什么 BDE-47 基于不同的降解机制表现出不同的脱溴途径。此外，氧被证明能够同时捕获电子和 H 原子，从而可以极大地抑制所有研究体系中 PBDEs 的降解。最后，详细讨论了每种金属掺杂 TiO 的优缺点，包括反应性、稳定性和副产物的生成。我们提出的研究极大地提高了我们对各种金属掺杂 TiO 体系中 PBDE 降解机制的理解。
