School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, PR China.
School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, PR China.
Chemosphere. 2019 Aug;228:232-240. doi: 10.1016/j.chemosphere.2019.04.103. Epub 2019 Apr 16.
The activities of heterogeneous Fenton and Photo-Fenton processes using pyrite (FeS) prepared via a solvethermal method were evaluated by oxidation of p-nitrophenol (PNP). PNP could be completely ultrarapidly oxidized by Pyrite-Photo-Fenton (Pyrite-PF) system within 4 min, versus 10 min in Pyrite-Fenton (Pyrite-F) system. The excellent oxidation performance obtained by Pyrite-PF might be due to accelerated circulation between ferrous ions and ferric ions under visible light illumination, which improved generation of reactive oxygen species (ROS). X-ray diffraction (XRD), scanning electron microscope (SEM), high resolution transmission electron microscopy (HRTEM), electron paramagnetic resonance (EPR) and X-ray photoelectron spectroscopy (XPS) were applied to ascertain the morphology and crystal structure of fresh-pyrite as well as used-pyrite. According to these results, the synthesized pyrite particles performed eminent stability, and used-pyrite could even generated more ROS including hydroxyl radicals (OH) and superoxide radicals (O). EPR testing and quenching experiments also confirmed the generations of OH, O and holes (h) during oxidation processes of PNP in both Pyrite-F and Pyrite-PF systems. The reaction pathway was proposed based on the detected intermediate products including 4-nitrocatechol, 4-nitropyrogallol, hydroquinone, benzoquinone, 1,2,4-trihydroxybenzene and 2,4-dinitrophenol. The mechanisms of PNP degradation in Pyrite-F and Pyrite-PF systems have also been studied by DFT calculations. Pyrite (111) should be responsible for the generations of free OH and surface OH.
采用溶剂热法制备的黄铁矿（FeS）用于非均相芬顿和光芬顿过程的活性评价，通过氧化对硝基苯酚（PNP）来进行。在 4 min 内，PNP 可被黄铁矿-光芬顿（Pyrite-PF）体系完全超快速氧化，而在黄铁矿-芬顿（Pyrite-F）体系中则需要 10 min。Pyrite-PF 获得的优异氧化性能可能归因于在可见光照射下亚铁离子和铁离子之间的加速循环，从而提高了活性氧物种（ROS）的生成。X 射线衍射（XRD）、扫描电子显微镜（SEM）、高分辨率透射电子显微镜（HRTEM）、电子顺磁共振（EPR）和 X 射线光电子能谱（XPS）被用于确定新鲜黄铁矿和使用后的黄铁矿的形貌和晶体结构。根据这些结果，合成的黄铁矿颗粒表现出卓越的稳定性，甚至使用后的黄铁矿也能生成更多的 ROS，包括羟基自由基（OH）和超氧自由基（O）。EPR 测试和猝灭实验也证实了在 Pyrite-F 和 Pyrite-PF 体系中 PNP 氧化过程中 OH、O 和空穴（h）的生成。根据检测到的中间产物，包括 4-硝基邻苯二酚、4-硝基邻苯三酚、对苯二酚、苯醌、1,2,4-三羟基苯和 2,4-二硝基苯酚，提出了反应途径。还通过 DFT 计算研究了 PNP 在 Pyrite-F 和 Pyrite-PF 体系中的降解机制。黄铁矿（111）应该负责生成游离 OH 和表面 OH。
