Preparation Of The Composite Catalyst Based SAPO-18 Zeolite And Study On Its Photo-fenton Catalytic Performance

As an advanced oxidation technology,Fenton oxidation has been widely used in wastewater treatment,industrial catalysis and other fields.However,the traditional homogeneous Fenton system has many disadvantages,such as the low reaction efficiency and the secondary pollution caused by the loss of iron ions easily.Therefore,the heterogeneous catalysts used for Fenton oxidation to load active components such as metal onto the support have emerged.The materials currently available for the support of heterogeneous catalysts include activated carbon,pore materials,zeolite and so on.Zeolite has a regular pore structure,is easy to be ion-exchanged,and has good stability.So it is a good support.The structure of zeolite is diverse.MFI type ZSM-5 zeolite,FAU structure Y zeolite and some two-dimensional materials have been used for Fenton oxidation research.The suitable support is also an important factor affecting the performance of the catalyst.In this thesis,the performance of composite catalysts with different zeolite supported Fe element was compared.By comparing the pore structure,the ratio of Si to Al and the amount of loading of different zeolite,the reasons for the difference in performance of the samples obtained by ion exchange of Fe elements were analyzed.AEI type SAPO-18 zeolite was used as the support,and two metal elements,Fe and Mn,were supported by ion exchange method.The properties were studied by UV/Fenton system for the catalytic degradation of methyl orange?MO?.And the reaction mechanism was analyzed.In addition,the performance of the catalyst and its reaction kinetics under different initial conditions were studied.The main results are as follows:?1?The template DMDMP of AEI type zeolite was synthesized,and SAPO-18zeolite was synthesized by traditional hydrothermal method.Fe/zeolite?referred to as Fe/Z?composite catalyst was prepared by using SAPO-18,USY,MCM-41 and SBA-15 zeolite to support Fe element by ion exchange method.And they were used to degrade the MO solution by UV/Fenton system.It is found that the catalytic performance of the Fe/SAPO-18 sample was significantly better than the other three samples.By comparing the pore structure,the ratio of Si-Al and the loading of the four kinds of support,we can conclude that the pore structure of the support has little effect on the performance of the composite catalyst;the low Si-Al ratio of SAPO-18may be an important advantage as support;the metal element loading of the catalyst also affects its performance;the strong absorption capacity of the composite catalyst for UV light after ion exchange does not necessarily promote the reaction efficiency of the UV/Fenton system.?2?SAPO-18 zeolite we prepared was used as the support to prepare the composite catalyst by ion exchange with the initial solutions with different Fe and Mn contents.And the catalyst was used to study the catalytic performance of degradation of MO by UV/Fenton system.The experimental results show that the ratio of Fe and Mn in the initial ion exchange solution was 2:1?denoted as Fe₂Mn₁/SAPO-18?,the obtained sample has the best catalytic performance and is superior to the single element loaded sample;all samples retain the original AEI-type skeleton structure after ion exchange treatment;the excellent performance of Fe-Mn/SAPO-18 samples is attributed to the synergistic effect of the two metal elements,the addition of UV light greatly increases the efficiency of the reaction system;terephthalic acid?TA?was used as a fluorescent probe to verify the promotion of active radical OH·by catalyst and UV light,and the possible reaction mechanism was analyzed;the change of catalyst performance and its reaction kinetics under different initial conditions were also studied.