Modification Of MOFs And Photo-fenton-catalyzed Degradation Of Bisphenol A

The photo-Fenton process has become one of the ideal technologies for treating difficult to degrade organic wastewater due to its advantages of fast degradation rate,high mineralisation capacity and controllable cost.However,conventional photocatalysts generally have the disadvantages of wide band gap and high carrier complexation rate,and their application prospects are severely limited.In this thesis,Fe doped metal organic frameworks(MOFs)functionalised with UiO-66 and MIL-53@ZIF-62,respectively,were prepared to address the above problems,modulating the catalyst band gap and improving the separated carrier transport,which in turn enhanced the reaction efficiency.The mechanism of action of the dynamic evolution process of the interface,the migration and transformation pathway of the active species and the degradation course of BP A are explored to elucidate the mechanism of MOFs functionalised material-mediated photo-Fenton.The details are as follows:(1)Fe-O-Zr bonding in MOFs enhances the photogenerated electron transport capacity to promote the efficient degradation of bisphenol A by photo-Fenton.the separation and transport capacity of photogenerated carriers are enhanced.The study modulates the intrinsic charge distribution of UiO-66 by introducing Fe elements,thus enhancing the electron gaining ability of the Fe sites(Fe average valence of 2.5).Related experiments and theoretical calculations revealed that the modification of UiO-66 by Fe elements to form Fe-O-Zr bonds led to an increase in the transport rate of photogenerated electrons,further enhancing the valence reduction anion of Fe and enhancing radical activation,resulting in a 100-fold increase in the removal efficiency of bisphenol A.(2)Modulation of the structure of MOF glass/crystal mixtures to alter the catalytic pathway and thus build efficient pathways for pollutant removal.The study transformed the original long-range ordered structure into a short-range ordered structure through the ZIF-62 vitrification process,exploiting the effect of the microstructure change on electron transport,resulting in a higher electron and proton transport capacity,and the degradation rate of the composite catalyst(4.71 × 10-2 min-1)was higher than that of ZIF-62(9.93 × 10-4 min-1)and MIL-53(9.17 × 10-3 min-1)by a factor of 47.4 and 5.14,respectively.Combined with the characterization of the surface acidity of the catalysts,the analysis suggests that the modulation of the surface acidity by the vitrification process may lead to the generation of different active species and catalytic pathways,this enhances the removal of pollutants.By combining LC-MS and theoretical calculations,etc.,reasonable speculations on the degradation and transformation processes of the pollutants are presented.This work explores in detail the catalysis at the solid-liquid interface by investigating the structural property changes such as photogenerated electron transport,active centre electron gain/loss,metal centre oxidation-reduction,and surface acidity regulation in the MOFs/hydrogen peroxide/visible light system.A theoretical basis for the development of efficient,green and cost-controllable photo-Fenton technology is provided.