The Preparation Of Heterogeneous Fenton Catalysts And The Research On Photocatalytic Degradation Of Phenol

Phenol and its derivatives are of great harm to the natural environment and human health.Fenton method is a kind of efficient and convenient way to purify the sewage.In order to research the degradation effiency of heterogeneous Fenton method for the treatment of wastewater,a phenol solution?50 mg/L?is used as the target to research in the study.Then the effect of different heterogeneous Fenton catalysts on the degradation of phenol was studied in the laboratory.In the paper,?-FeOOH,?-FeOOH,Fe₂O₃,Fe₂O₃/?-Al₂O₃ and Fe₂O₃/CuO/?-Al₂O₃ were prepared as heterogeneous catalysts to degrade phenol solution under the UV light of 254 nm.The morphology and physicochemical properties of the catalysts were characterized by XRD,SEM,TEM,HRTEM,FTIR,and DRS.And the ICP was used to measure the ion leaching of iron and copper.Some important operational parameters,such as pH value,reaction temperature,calcination temperature,catalysts dose and hydrogen peroxide concentration,were researched in the work to ensure the optimal degradation conditions.At the same time,the influence of various parameters on the degradation rate of phenol was determined by orthogonal experiment.The orthogonal experiment results showed that the influence factors of the parameters are pH?reaction temperature?H₂O₂ concentration?catalyst dosage.The Fe₂O₃/?-Al₂O₃ and Fe₂O₃/CuO/?-Al₂O₃catalysts were prepared by ultrasonic impregnation method in ice-water bath.Through the characterizations of the catalysts,it is proved that the catalyst particles uniformly distributed on the surface of the carrier.This structure can not only enhance the adsorption effect of catalysts for phenol molecules,but also improve the utilization rate of the ultraviolet light to a certain extent.In addition,the results of a variety of catalysts on the degradation of phenol showed that compared with a single iron based catalyst,the composite catalyst can improve the efficiency of degradation and shorten the time of degradation.In the experiments,the degradation efficiency of Fe₂O₃/?-Al₂O₃ was 90.1%in 4 h,while that of Fe₂O₃/CuO/?-Al₂O₃ reached 92.3%in 2 h at a pH of 3.5.Additionally,it should noted that at pH 4.5 and 5.5,the Fe₂O₃/CuO/?-Al₂O₃catalysts presents a certain amount of degradation rate,88.0%and 75.6%,respectively.While the degradation rate of Fe₂O₃/?-Al₂O₃ catalysts are 73.1%and 41.4%at the pH of 4.5and 5.5.It is due to the fact that the number of active sites is increased by doping copper and copper could play a dominant role in the catalytic process of Fenton reaction at a pH higher than 4.Meanwhile,iron would further promote the catalytic performance at a relative wide pH range.The synergistic effect of cupper ions and iron ions can improve the degradation efficiency and reduce the reaction time.This result plays a guiding role for the principle of heterogeneous Fenton degradation.In the end of the experiment,we also researched the stability of the Fe₂O₃/CuO/?-Al₂O₃catalysts.The ICP detected that the ion leaching of iron is 0.18mg/L,but the copper ions are not detected in the study.The results showed that the degradation rate Fe2O3/CuO/?-Al2O3catalysts performed 79%in 4 h after the 3th consecutive reuse of the catalyst,which was about 13%lower than that of Fe2O3/?-Al2O3 catalysts.