Li Puma Gianluca
School of Chemical, Environmental and Mining Engineering, The University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom.
Environ Sci Technol. 2003 Dec 15;37(24):5783-91. doi: 10.1021/es0300362.
Photocatalytic oxidation over titanium dioxide is a "green" sustainable process for treatment and purification of water and wastewater. A dimensionless model for steady-state, continuous flow, thin-film, slurry (TFS) photocatalytic reactors for water purification using solar radiation and UV lamps is presented and validated. The model is applicable to TFS flat plate and annular photoreactors of (a) falling film or (b) double-skin designs, operating with three ideal flows: (1) falling film laminar flow (FFLF), (2) plug flow (PF) and (3) slitflow (SF). Model parameters can be estimated easily from real systems, and solutions can be obtained with modest computational efforts. A modified two-flux absorption-scattering model models the radiation field in the photoreactor. Model simulations show that at a scattering albedo higher than 0.3, radiation scattering can significantly affect conversions obtained at different values of optical thickness. However, at lower values, the effect of scattering on conversions is negligible. The conversions with the idealized flow systems follow the sequence FFLF > PF > SF. SF operation should always be avoided. The model estimates the optimum value of optical thickness that maximizes conversion in a photocatalytic reactor. Optimal design of TFS photocatalytic reactors using the photocatalyst TiO2 Degussa P25 requires an optical thickness in the range from 1.8 to 3.4 depending on flow conditions and reaction kinetics.
二氧化钛光催化氧化是一种用于水和废水处理与净化的“绿色”可持续工艺。本文提出并验证了一个用于稳态、连续流、薄膜、浆液（TFS）光催化反应器的无量纲模型，该反应器利用太阳辐射和紫外线灯进行水净化。该模型适用于（a）降膜或（b）双层设计的TFS平板和环形光反应器，其操作具有三种理想流型：（1）降膜层流（FFLF）、（2）活塞流（PF）和（3）狭缝流（SF）。模型参数可从实际系统中轻松估算，且通过适度的计算工作即可获得解决方案。一个改进的双通量吸收 - 散射模型对光反应器中的辐射场进行了建模。模型模拟表明，当散射反照率高于0.3时，辐射散射会显著影响在不同光学厚度值下获得的转化率。然而，在较低值时，散射对转化率的影响可忽略不计。理想化流型系统的转化率遵循FFLF > PF > SF的顺序。应始终避免采用SF操作。该模型估计了使光催化反应器中转化率最大化的光学厚度的最佳值。使用光催化剂二氧化钛Degussa P25的TFS光催化反应器的优化设计需要根据流动条件和反应动力学，将光学厚度控制在1.8至3.4的范围内。
