| The indoor environment pollution problem is very serious and the photocatalytic technology undoubtedly gives us a very novel idea. The use of photocatalytic degradation of indoor air pollutants and more and more people are interested and join in photocatalytic technology. The photocatalytic reactor is the carrier of photocatalysis technology. The dynamic process inside the reactor is complex and has many influencing factors.photocatalytic reactor has become a key step in the successful application of photocatalytic technology. In this paper, formaldehyde as the target pollutants in the self-design reactor and the processing reaction to studied: the kinetic process of photocatalytic reaction. And the factors influencing the design and optimization of the reactor and the degradation process in the reactor are discussed in detail.The main conclusions of this paper are as follows:(1)Based on the kinetics of photocatalytic degradation, the existing catalyst thickness model was analyzed and the theoretical thickness model of the metal nickel net was used to find the best film thickness. The experimental results show that the model thickness is very good. The thickness of the photocatalytic film was measured using the foamed nickel net as the carrier. Both the experimental results and the predicted results show that when the thickness of the catalyst increases,the degradation rate first increases and then stabilizes.The results show that the optimal catalyst thickness is 86 nm, which is consistent with the predicted value. Under the same conditions, compared with other catalysts such as. TiO2,Cu2O, BiVO4 and g-C3N4, the degradation rate of formaldehyde increases first Stable at a certain value. The experimental results show that the optimal catalyst thickness is 86nm.Indicating that this model is suitable for other different types of catalysts(2) In order to select materials with better photocatalytic properties, its performance evaluation through structural analysis and experimental (the size, specific surface area,band gap) and performance evaluation. By analyzing the structure and degradation of formaldehyde, it was found that the degradation efficiency of all of the catalysts showed an upward trend and TiO2-1 ( T-1 ),TiO2-2 (T-2) increased significantly with increasing concentration of formaldehyde.With the environment humidity increased, the degradation efficiencies of the catalysts were first increased and then decreased. BiVO4-1 ( B-1 ),BiVO4-2 (B-2) degradation rate decreased more slowly. The same material as the grain size is smaller, the greater the specific surfacearea, having the higher degradation rate.T-2 had a better stability than B-1. This provides a much more efficient and stable photocatalyst for the design of the next reactor.(3)Based on the principle of high efficiency and energy saving, four kinds of photocatalytic reactor were designed for the coordination of formaldehyde, photon and catalyst, and their photocatalytic degradation performance was studied experimentally. The Stanton number (Stm) and adsorption equilibrium constant (K) of the plate reactor (type 1)are large, indicating that the convective mass transfer capacity is strong, but the reaction efficiency ? and reaction rate constant k are obviously small, Reaction capacity is poor,mass-reaction capacity does not match. When n is close to 0.5, the reaction rate and mass transfer rate are equivalent, and the mass transfer-reaction capacity of the catalyst is matched. So the best effect is 45 -type reactor... |
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