A Methodology for Modelling Slurry Photocatalytic Reactors for Degradation of an Organic Pollutant in Water.

ALFANO, O. M.; CASSANO, A. E.; BRANDI, R. J.; SATUF, M. L.

Photocatalysis and Water Purification. From Fundamentals to Recent Applications.

Editorial Wiley-VCH Verlag GmbH & Co. KGaA

Lugar: Weinheim; Año: 2013; p. 335 - 359

In the beginning of a more recent era of photocatalysis, new work oriented towards the use of visible light would extend all its possibilities of application from those conceived from 1970 to the present. The goal is to modify the catalyst properties by adding chemical elements so it can be activated by the visible spectrum of the sun. Since 1993, our group has been dedicated to the study of photocatalytic processes, developing procedures to obtain quantitative reaction kinetic models and reactor scaling-up. The idea is to move from especially designed laboratory experiments to the commercial size apparatus in one step. To achieve this objective, it is necessary to analyze both equipments with rigorous mathematical modelling, involving the solution of the complete Radiative Transfer Equation (RTE). To work in the laboratory reactor, one starts with a kinetic scheme and derives a kinetic model. To analyze the results, it is necessary a mass balance. For the irradiated steps, the photon absorption rate must be known. Here, it is indispensable to have information about the radiation that arrives at the reactor wall and the optical properties of the catalyst (absorption coefficient, scattering coefficient and the phase function). With this data, the results of the kinetic experiments are compared with those obtained from the simulation of the kinetic model resorting to a non linear, multi-parameter estimation to render the kinetic constants. For scaling-up purposes (changing the reactor shape, size, lamps, and configuration), the same approach must be followed, directly applying the kinetic equations to the new reactor and solving the radiation model. There is only one limitation to this practice: the lamps spectral wavelength distribution of both systems must be very similar. In what follows, we will present in detail the modelling and scaling-up of a slurry reactor, from laboratory scale to bench scale size, for the photocatalytic degradation of a model pollutant: 4-chlorophenol.