Preparation And Photocatalytic Performance On Dye Wastewater Of Modification Nano-TiO₂

Because of non-toxic, easily production, as well as an effective and broad spectrumperformance, TiO₂photocatalysis technology has been received extensive attention in printingand dyeing wastewater treatment. But the ordinary TiO₂photocatalyst can only absorbultraviolet light and its inefficient catalytic efficiency have led difficultly to realize TiO₂forthe industrial application. Therefore, improving its photocatalytic property and achieving TiO₂photocatalyst utilize sunlight have recently become a hot study field of photocatalytictechnology. It was practicable that ameliorating the synthetic method and modifying TiO₂photocatalyst by studies.In the present paper, to prepare Fe and N doped TiO₂photocatalyst separately, and theinfluences of preparation conditions for catalytic performance were investigated by theorthogonal testing method. A series of high performance of modified TiO₂photocatalysts hadbeen synthetized with optimize preparation. Then, the degradation properties and degradationmechanism in the degradation of simulated dye pollutants for printing and dyeing wastewaterwere studied under different light source with the above photocatalysts. The study contents ofthis paper are enumerated as follows.1. TiO₂photocatalysts doped respectively with Fe and N were prepared by sol-gelmethod. Then, the influences of assembly time, dosage, calcination temperature andcalcination time of the properties of the TiO₂photocatalysts were studied by orthogonaltesting method. Moreover, the optimal synthesis conditions for preparing nano-TiO₂photocatalyst which had excellent catalytic performance under ultraviolet light and sunlightwere optimized. Scanning electron microscope （SEM）, X-ray diffraction （XRD）and X-rayphotoelectron spectroscopy （XPS） were respectively employed to analyzed the four optimizedsamples’ surface features. The results showed that degradation rate of the photodegradatedmethylene blue under ultraviolet light and sunlight of the four samples could reached95%,and the four samples were all anatase nanoparticle, and its crystal sizes were all about10nm,all of which illustrated that the sol-gel method was suitable to prepare modified nano-TiO₂photocatalyst, and Fe and N doped TiO₂had better improved the catalytic performance, andexpand the light response range to visible light region.2. A set of nano-TiO₂photocatalyst doped Fe and N respectively were prepared byhydrothermal synthesis method. The influences for the property of catalysts of assembly time, dosage, hydrothermal reaction temperature and hydrothermal time were studied. From theexperiment of degradated methylene blue, the main conclusions were that the best nano-TiO₂photocatalyst should be prepared with the corresponding light source. With characterizationresearched, four optimized samples had successfully doping with Fe and N. They were allanatase nanoparticle, and photocatalytic degradation of methylene blue were above95%inthe ultraviolet and visible light.3. The eight nano-TiO₂photocatalyst samples which optimizing prepared by sol-gelmethod and hydrothermal synthesis method above, their higher photocatalytic degradationefficiency showed up in the degradation of methyl orange and malachite green and its mixedwastewater. But there were not appear the consistent regularity compared with theirdegradation of methylene blue. The results explained that the optimize preparation conditionsof modified nano-TiO₂photocatalyst should be based on the target degradation of dye.