Study Of Doped Nano-sized Titanium Dioxide And Photocatalytic Oxidation Of Basic Magenta

In recent years, with the development of photoelectrochemical semiconductor and preparation of material, more and more attention is paid to research sewage treatment by photocataytic oxidation technique, and some promising progress has been made. Because of its strong ability of oxidation and high removal rate of organic pollutants, compared with traditonal technologies in pollotion abatement, photocatalytic technique has distinctive advantages in removal of organic especially in removal of some preferential carcinogenic organic.In this paper, mercury lamp was used as radiant light and titanium dioxide powder as catalyst. Basic Magenta has been treated. Firstly, the influence factors of photocatalytic reaction such as concentration of catalyst, concentration of alkaline fuchsin,reaction time, pH value and light intensity has been studied. Secondly, nano-sized titanium dioxide had been prepared via the sol-gel method. Results showed that the reactive activity of self-made T1O2 is much better than that of commercial TiO2. Thirdly, in order to improve its photocatalytic activity, the nanometer TiO2 doping with metallic ion had been studied.The testing results of XRD and TEM showed that the average grain size of self-made nano-sized TiO2 and that of TiO2 doping with Fe3+ are 20 nanometers and15 nanometers. Finally, TiO2 photocatalytic reaction radiated by sunshine, pretreatment of sewage by ultrasound, the degradation dynamics of Basic Magenta and mechanism of photocatalytic reaction had also been discussed.The results showed that the optimal concentration of TiO2 was 1.5g/1. And the lower the initial concentration of the dyestuff, the more powerful the photocatalytic oxidation was. The lower the depth of sewage in the reactor, the higer the removal rate of it was. The degradation of organic pollotants could be improved when oxidizer or alkaline were added to the reactor. Higher light intensity could enhance the removal rate of organic in this experiment. The experimental results showed that the photocatalytic activity of self-made nano-sized TiO2 was much better than that of commercial TiO2. The decoloration rate of Basic Magenta sewage could be 96.7%, and the removal rate of CODCr could be 52.8%. The photocatalytic activity of TiO2 doping with Fe3+ was better and it could improve the decoloration rate and the removal rate of CODcr to 98.8% and 65%. The optimum concentration of Fe3+ was 0.06%. The uv-vis spectrum showed that the light absorb intensity of TiO2 doping with Fe3+ was much higher in visible light area. In the experiment of photocatalytic reaction radiated by sunlight, the reactive performance of TiO2 doping with Fe3+ was better than that of other TiO2 and the decoloration rate of Basic Magenta sewage could be 95%. Pretreatment by ultrasound could improve the dispersion of nano-sized TiO2 particles. Longer time, lower temperature and proper power of ultrasound treatment could also enhance the degree of dispersion of T1O2 particles. The studies in the degradation dynamics of Basic Magenta showed that the photocatalystic oxidation was first order reaction when the initial concentration of Basic Magenta was low. And the reaction was zero order when the initial concentration of fuchsin was high. The experimental results showed that the photocatalytic degradation process of Basic Magenta fit with the Langmuir-Hinshelwood model. Under this experimentalconditions, the kinetics equation was...