The Influence Of Different Preparation Method On Double Catalytic Activity Of Co-TiO₂ Catalyst

How can quickly and efficiently process organic wastewater has been the technical difficulty in research of sewage treatment.Cobalt mediate Potassium peroxymonosulfate(Co/Oxone) produce sulfate radicals(SO4?-), which is a promising refractory organic wastewater treatment technology and one of Fenton-like reactions through the coupling of a transition metal with an oxidant, and a very small amount of Co can efficient catalyze Oxone over a wide p H range(4 <p H <9), the sulfate radical has a higher redox potential, a longer time, more selective compared with the hydroxyl radical, can fully mineralized organic matter, to overcome shortcomings of the traditional Fenton method that p H range is narrow, H2O2 dosage is great, can not complete mineralization of organic matter, and so on.The paper supported Co on Ti O2, developed a new and high efficiency double effect Co-Ti O2 catalyst,and use the catalyst,light and Oxone constructed the SR-Fenton/Photo synergistic oxidation system based on SO4?-, realize the combination of SR-Fenton and photocatalytic,but also to overcome shortcomings of the homogeneous Co/Oxone catalyst system that catalyst can not be recycled, Co ion release.The catalyst preparation method affects the catalytic activity of doped Ti O2 directly.The paper prepared Co-Ti O2 catalysts by hydrolysis precipitation method, sol-gel method and impregnation method, the catalysts were characterized by X-raydiffraction(XRD), ultraviolet diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy(XPS) and scanning electron microscopy(SEM) technologies. Methylene blue(MB) was used as model organic pollutant,while SR-Fenton/Photo complex affect and dissolution of cobalt used as evaluation index to study the influence of different prepartion methods. The influence of catalyst dosage,solution p H and Oxone dosage on degradation of MB by Vis/Co-Ti O2/Oxone system were also investigated.What’s more, the influence of different catalyst calcined temperature and cobalt amounts on activity of catalysts prepared by sol-gel method were also investigated.The main contents and conclusions of the paper are as follows:1) Co-Ti O2 catalysts were prepared by hydrolysis precipitation method, sol-gel method and impregnation method, the results show that three kinds of catalysts were anatase Ti O2. The main oxide of the sample prepared by hydrolysis precipitation method and impregnation method were Ti O2, Ti- OH or Co-OH and Co3O4 formed in the surface of Ti O2. The main oxide of the sample prepared by sol-gel method were Ti O2, little Co3O4 formed in the surface of Ti O2.UV diffuse Co-Ti O2 catalysts characterization that the absorption edge is moved to a red 890 nm, said Co-Ti O2 catalysts can be visible excited. Co-Ti O2 catalysts were micron-sized particle.2) Co-Ti O2 catalysts prepared by hydrolysis precipitation method represented SR-Fenton and photocatalytic double catalytic activity. The best catalyst dosage of catalysts prepared by hydrolysis precipitation method was 0.5g/L in Vis/Co-Ti O2/Oxone system.System had the best performance under the near-neutral conditions(4<p H<7).The optimum amount of oxidant by catalyst prepared by hydrolysis precipitation method was n[Oxone]=0.75 m M. Recycle of catalyst prepared by Hydrolysis precipitation method, the catalyst activity was significantly decreased, stability of the catalyst could be improved.3) Co-Ti O2 catalysts prepared by impregnation method represented SR-Fenton and photocatalytic double catalytic activity. The best catalyst dosage of catalysts prepared by impregnation method was 0.5g/L in Vis/Co-Ti O2/Oxone system.System had the best performance under the near-neutral conditions(4<p H<7).The optimum amount of oxidant by catalyst prepared by impregnation method was n[Oxone]=1m M. Recycle of catalyst prepared by impregnation method, the catalyst remains good catalytic activity.4) Co-Ti O2 catalysts prepared by sol-gel method represented SR-Fenton and photocatalytic double catalytic activity. The best catalyst dosage of catalysts prepared by sol-gel method was 1g/L in Vis/Co-Ti O2/Oxone system.System had the best performance under the near-neutral conditions(4<p H<7).The optimum amount of oxidant by catalyst prepared by sol-gel method was n[Oxone]=1m M. Recycle of catalyst prepared by sol-gel method, the catalytic activity of Co-Ti O2 powders prepared by sol-gel method had good reproducibility.5) The radical quenching method recognizes under the condition of UV-light, ?OH and SO4?- both exist in the hybrid system, and MB was degraded by SR-Fenton/Photo complex affect.6) Three kinds of catalysts represented good photocatalytic activity, Co-Ti O2 catalysts prepared by hydrolysis precipitation method was highest among them. Co-Ti O2 catalysts prepared by impregnation method showed highest SR-Fenton activity. Degradation rate of MB in Vis/Co-Ti O2/Oxone system size order for hydrolysis precipitation method, impregnation method and Sol-gel method. From an environmental point of view, the best preparation method was the sol-gel method because Co ion release of sol-gel method was the least amount.