Description On Photocatalytic Degradation Of Typical Dyes In Aqueous Solution And Modeling Design Of A Novel Photocatalytic Reactor

The research began with preparation of superfine photocatalyst, which can be magnetically separated from liquid, and then based on the experiments of adsorption and photocatalytic degradation of two typical organics the possible degradation schemes and processes were proposed, the isotherm and rate equation were established respectively. Finally, a novel rotated photocatalytic reactor was designed and used in experiments of photocatalytic degradation of organics. According to the measurement of profile of UV intensities in reactor and the reaction kinetics, a model for the reactor design was built. The simulated results coincided with experimental data. Following is the detail.A synthesis method was used to prepare a novel photocatalyst with magnetite core for resolving the problem of separating catalyst particle from liquid. Magnetite matrix Fe3O4 was prepared by coprecipitation andγ-Fe₂O₃ obtained by Fe₃O₄ annealed at higher temperature, thenγ-Fe₂O₃ as core was coated with Al₂O₃ film by coprecipitation too, TiO₂/ Al₂O₃/γ-Fe2O3 photocatalyst was successfully prepared by sol-gel method. The surface morphology and crystal structure of the catalyst were characterized by TEM and XRD respectively. The photocatalytic activity of this catalyst was determined with NTS and 4BS as decomposition substances. The experimental results showed that the photocatalyst TiO₂/ Al₂O₃/γ-Fe₂O₃ can be dispersed in aqueous solution easily and separated from solution by the magnetic field rapidly. The chemical NTS can also be almost totally degraded within 95 min by using a 250W UV lamp.The adsorption of 4BS dye on superfine particle of TiO₂ was studied experimentally and isotherms of Langmuir were obtained at different temperatures and pHs.Photocatalytic degradation of 4BS dye on TiO₂ powder in a slurry reactor was also researched. After analysis of degradation scheme and consideration of ultraviolet intensity, pH value of dye solution, amount and dispersion situation of catalyst in the liquid a kinetics of photocatalytic degradation of 4BS dye was established. The kinetic model can describe the degradation process from beginning to the end, which can provide theoretical basis for design of reactor.As a critical apparatus in wastewater treatment, a novel photocatalytic reactor...