Surface Loading Of Titanium Dioxide And Metal Phthalocyanine Catalysts For Fly Ash

The Catalytic oxidation technology is an important strategy for purification of contamina nts in water.Some catalyst's active sites will probably be embeded in the process of water poll ution treatment,which resulting in the low catalytic efficiency and secondary pollution and so on.Therefore,many catalysts can be immobilized on the appropriate carriers by using suitabl e physical or chemical methods for the cyclic utilization of catalysts as well as preventing the diffusion pollution of these catalysts in environment.So catalyst loading is a practical researc h work.In this study,two catalysts were supported on surfaces of fly ash?FA?.?1?Titanium di oxide?TiO₂?was prepared at low temperature and immobilized on FA surface via in situ grow th for TiO₂/FA;?2?Octacarboxyl ferric phthalocyanine?OCFePc?was prepared by two steps a nd and precipitated on FA surface by physical adsorption for OCFePc/FA.Many modern mate rial characterization technologies were performed on the as designed catalysts.Rhodamine B,methyl orange,methylene blue and other organic dyes were used as simulated pollutants to in vestigate the degradation ability of the two supported catalysts.The catalytic mechanism was proposed based on the measurement results.This thesis mainly includes the following three aspects:?1?Preparation of the crystal phase structure by using hydrofluoric acid?HF?doping modified TiO₂ to control HF-TiO₂,study the effect of the addition amount on the crystal structure of the TiO₂ and its catalytic performance under UV light.The auxiliary addition of hydrofluoric acid in a certain concentration range fine-tuned the light response range of TiO₂,but would greatly enhance its photocatalytic degradation performance against rhodamine B?Rh B?.If the HF addition amount is too large,the TiO₂ nanostructures will be corroded and destroyed,which makes the photocatalytic degradation performance lower,in which the incorporation of 0.1 mLHF compared with 0.08 will reduce the photocatalytic efficiency by50%.The electron spin resonance?ESR?detection technique confirms that TiO₂ produce hydroxyl radicals on the surface as active radical species during the photocatalytic process.?2?The TiO₂ was fixed to the surface of fly ash microspheres by chemical deposition,and the surface of fly ash was covered with a uniform TiO₂.Comparing the supported TiO₂ uv catalytic performance with pure TiO₂,it was found that the TiO₂ loading in the synthesized TiO₂/FA was only 1.4%of the pure TiO₂ mass at the same amount of use and under the same catalytic conditions,the degradation rate was 70%of the unmodified pure TiO₂ at the same time,and the catalytic efficiency increased 35 times after loading to the FA surface.?3?The OCFePc was loaded on the surface of fly ash microspheres by physical adsorption method.The sturctures of as prepared catalysts were confirmed by scanning electron microscope,X-ray powder diffractometer and infrared spectroscopy,respectively.Tert-butyl hydroperoxide was selected as oxidant to construct catalytic oxidation system,and methyl orange and methylene blue were used as simulated pollutants to evaluate their degradation performance.The results showed that the spherical surfaces of the OCFePc/FA with a 5 wt%of catalyst loading had obvious coverage effect,degradation rate of the 25mg/L methylene blue in 20 minutes and 10 mg/L methylene blue in 30 minutes could achieve more than 90%and the dye decolorization process was in accordance with the quasi-first-order kinetics.Electron spin resonance?ESR?detection technique confirms that tert-butyl peroxy radical and hydroxyl radical are the active radicals produced by the catalytic system,both of which cooperated with the high-valent ferrite active species to catalyze synergistically the rapid degradation reaction of dyes.