Synthesis Of α-Fe₂O₃ Ultrathin Nano-sheet And Degradation Of Bisphenol S By Photo-fenton

Bisphenol S is an endocrine disruptor（xenoestrogen）. In the process of manufacture and use, it will accumulate in the water, harmful to the natural environment and human health. And it is difficult to remove by conventional water treatment processes. Fenton technology can mineralize refractory organics with hydroxyl radical（HO·） producing by the decomposition of H₂O₂. However, there are some disadvantages in the traditional Fenton technology, including narrow p H adaptation range, low H₂O₂ utilization efficiency, iron difficult to recycle and produce secondary pollution. Based on the above background, the present study tend to synthesize a cheep and effective heterogeneous catalyst and build a heterogeneous visible-photo-Fenton system to overcome the drawbacks of the conventional technique, achieving efficient removal of bisphenol S in water.In this study, an iron oxide nano-sheet with high-energy crystal plane is synthesized by one-step hydrothermal synthesis, using ferric acetylacetonate as precursor and Si O₂ nanoparticles as the template, at the reaction temperature of 220°C and reaction time of 24 h. The characterization result shows that α-Fe₂O₃ nano-sheet is of high purity as well ad crystallinity. It is about 100 nm in size, but thickness is only 3-4nm. Specific surface area is up to 102.3 m2/g. It also has a dielectric hollow structure and a high exposed proportion of high-energy（110） planes. In addition, absorption intensity of ultraviolet and visible spectrum is both high, showing a an excellent visible-photo catalytic activity.In he heterogeneous visible-photo-Fenton System, Fe₂O₃ nano-sheet, H₂O₂ and visible-photo shows a synergistic effect in the degradation of bisphenol S. And the system attain the highest BPS degradation rate when the initial concentration of BPS and H₂O₂ is 20mg/L and 6.67mmol/L, Fe₂O₃ dosage is 200mg/L and p H is 5.5±0.2. The biggest iron ions concentration in the system is 0.11mg/L, less than the national standard limit of drinking water. The effcet of Fe₂O₃ recycling use on the degradation of bisphenol S is insignificant. So the synthesized Fe₂O₃ has good catalytic stability and practicability.Detection and analysis result shows that the major oxide active of the system including: hydroxyl radical（HO·） and superoxide radical（·O₂-）. Visible illumination can promote the production of HO·. Based on the results of this study and the photocatalytic theory, the mechanism of the degradation of bisphenol S in heterogeneous photo-Fenton is inferred.