Ipnpact of photocatalyst optical properties on the efficiency of solar Ipiotocatalytic reactors rationalized by the concepts of initial rate of photon Absorption (IRPA) dimensionless boundary layer of photon absorption and apparent optical thickness

摘要

The concepts of "initial rate of photon absorption" (IRPA), "duriensionless bouridary layer of photon absorption" and "apparent optical thickness (ι_(app)" are presented toevaluate the radiative transfer phenomena in solar, slurry, planar, photocatalytic reactors. The radiation: field produced by suspensions of TiO2 and goefhite, two photocatalysts with profoundly different optical properties used inrheterbgerious phbtocatalysis and heterogeneous photo-assisted Eenton reactions, was determined by the six-flux radiation absorption-scattering model coupled to the Henyey-Greenstein scattering phase function (SFM-HG). The concept of IRPA, defined by the differentiation at the local volumetric rate of photon absorption (LVRPA) at the reactor window boundary, is proposed as a new. approach to determine the impact of catalystloading and optical properties on the extinction of light inside a photoreactor. the IRPA showed that the extinction of light follows a second order dependency on the photocatalyst concentration while the impact of the optical properties can be expressed by a decoupled function (Ψ function), the Ψ fuction increased with photocatalyst concentration and approached a maximum at the same optimal photocatalyst concentration determined from the analysis of the total rate of photon absorption (TRPA) in the reactor. The analysis of TBPA and boundary layer of photon absorption redefined here in dimensionless form, as a function of τ_(app) determined that the most efficient rate of radiation absorption in solar powered planar'reactorsoccurs at τ_(app) with approximately 10% of the reactor width under darkness. τ_(app) is a similarity dimensionless parameter exclusively derived from the SFM approach, which clustes the effects of photocatalyst loading, reactor dimension and photocatalyst optical properties, providing an ideal parameter for designing and scaling photocatalytic reactors operated with any kind of photocatalytic material.