Fe3O4/FeS2活化H2O2降解典型苯胂酸类污染物

利用水热法成功制备了Fe₃O₄/FeS₂催化剂，并将其用于构建非均相芬顿体系降解典型的苯胂酸类污染物（洛克沙胂，ROX）.XRD、SEM、XPS和磁学测量系统（VSM）等表征结果表明，Fe₃O₄/FeS₂呈明显的颗粒状且具有良好的磁性.降解实验结果显示，在最优条件下（初始pH值为4.5、ROX起始浓度为20mg/L、Fe₃O₄/FeS₂投加量为0.15g/L和H₂O₂浓度为0.034g/L，Fe₃O₄/FeS₂介导的非均相芬顿体系可以超快速降解ROX，1min后的降解效率达到96.74%，明显优于单独的Fe₃O₄或FeS₂体系.此外，Fe₃O₄/FeS₂可以通过磁铁进行快速回收利用，同时也具有良好的重复利用性能，使用3次后，ROX的降解效率仍超过80%.机理分析表明，Fe₃O₄/FeS₂能够快速地催化H₂O₂产生具有强氧化性的羟基自由基（·OH）.在·OH的作-用下，ROX分子结构中C-As、C-N和C-C等化学键发生断裂，发生脱砷、脱硝和开环等反应，进而生成一系列的有机产物（如酚类、醌类、小分子有机酸等）和无机产物（As （V）和NO₃^-）.之后，无机砷能够被吸附在催化剂表面，而有机产物则进一步被矿化.

Fe3O4/FeS2 activated H2O2 degradation of typical phenylarsonic acid pollutants

Fe₃O₄/FeS₂ catalyst was successfully prepared by hydrothermal method, and employed to mediate a heterogeneous Fenton system for the remediation of a typical phenylarsonic acid pollutant (roxarsone, ROX). The characterization results of XRD, SEM, XPS and magnetic measurement system (VSM) showed that Fe₃O₄/FeS₂ displayed evident granular particles and good magnetic properties. The results of ROX degradation experiments showed that under optimal conditions (4.5of the initial pH, 20mg/L of ROX initial concentration, 0.15g/L of Fe₃O₄/FeS₂ dosage and 0.034g/L of H₂O₂ concentration), the heterogeneous Fenton system could instantaneously degrade 96.74% of ROX in 1min, which was much better than of the systems mediated by sole Fe₃O₄ or FeS₂. In addition, Fe₃O₄/FeS₂ could be effectively recycled by magnets, and also exhibited good reusability. After 3 runs, the degradation efficiency of ROX was still over 80%. Mechanism analysis revealed that plenty of hydroxyl radicals (·OH) could be generated via the catalytic reaction between Fe₃O₄/FeS₂ and H₂O₂. Subsequently, the ·OH could quickly attacked the C-As, C-N, and C-C bonds in the ROX molecule, resulting in the dearsenication, denitrification and ring opening reactions, as well as the formation of a series of organic products (such as phenols, quinones, small molecular organic acids, etc.) and inorganic products (As(V) and NO₃^-). Finally, the released inorganic arsenic could be adsorbed on the surface of the catalyst, while the organic product was further mineralized.