The Studies Of Photocatalytic Degradation Of Heptylene On Iron-doped TiO₂ Nanoparticles

Volatile Organic Compound(VOC_S) spread widely in the environment of water, soil and atmosphere. Many VOC_S are the matter with toxicity. At the present time, people generally adopt the methods of catalytic combustion ,chemical oxidization ,adsorption and biological filtration, and so on, to remove VOC_S. But these methods have some limitation. Therefore, how to remove VOC_S with economical,effective and secure method is still an important subject which needs to research. In the recent twenty years, many research in the region of photocatalysis have shown that photocatalysed method can effectively decompose many kinds of VOC_S, turn VOC_S to CO2 and H2O thoroughly and the reaction of phtocatalysis may proceed in ordinary temperature and pressure at low cost. TiO₂ has been widely applied to the research of the photocatalytic degradation of organic contaminant because it is innocuous,cheap,stable and with higher photocatalytic activity. The absorption spectrum of TiO₂ lies in ultraviolet spectrum, so the utilization ratio of sunlight is not high ,and photoinduced electron and hole have such high recombination rate that the photocatalytic activity of TiO₂ decline. To enhance the practicability of TiO₂ photocatalyst, the key is how to change its character of absorption and decrease the recombination rate of photoinduced electron and hole. Nowadays, doping transition metal ions is one of the remarkably methods to enhance the photocatalytic activity of TiO2.In the view of chemistry, metal ions are the effective acceptor of electron. Owing to metal ions capturing electron and decreasing the recombination rate of photoinduced electron and hole of the surface of TiO2, the surface of TiO2 produce more ·OH and O22-and accordingly the photocatalytic activity of TiO2 increase. In this paper, we use Fe3+ to modify TiO2. Iron-doped TiO2 nanoparticles were prepared via a new synthetic route. Firstly we selected different synthesis conditions (the sort and density of reactant, the amount of HNO3, the time of water bath, calcination temperature and the amount of iron dopant ) to prepare iron-doped TiO2 nanoparticles. The photocatalytic activity of iron-doped TiO2 nanoparticles under different synthesis conditions was examined by the photocatalytic degradation of heptylene, accordingly optimizing experiment and preparing the optimum iron-doped TiO2 nanoparticles. The properties of the samples are characterized by means of XRD, TG-DTA ,XPS and UV-Vis. At the same time, simulating the ratio of Fe to Ti in the actual atmospheric environment and preparing the sample with different ratio of Fe to Ti ,we review the possibility of the heterogeneous photocatalytic oxidizing reaction of orgnic matter on atmospheric solid aerosols. The photocatalytic activity of iron-doped TiO2 nanoparticles is the highest when we use NaOH as precipitant and its density is 2.352mol/L, the amount of HNO3 is 4ml, the time of water bath is 20min, the mole ratio of Fe to Ti is 0.5% and the calcination temperature is 300℃. The analysis results metioned above indicate that the iron doping...