Mathematical modelling of pilot-plant photomineralization of chlorophenols in aqueous solution, by photocatalytic membranes immobilizing titanium dioxides
Photomineralization of 4-chloro phenol, 2,4-dichloro phenol, and pentachloro phenol, in aqueous solutions, in the presence of stoichiometric hydrogen peroxide, was studied using PHOTOPERM CPP/313 membranes containing immobilized TiO(2), by following both disappearance of absorbable chloro-organics (AOX), and mineralization of total organic carbon (TOC). Experiments were carried out in a PHOTOPERM WP pilot plant using monochromatic irradiation (254 nm). The initial rate of photodegradation (AOX and TOC) was studied as a function of the initial concentration of substrate using the linearized form of the Langmuir-Hinshelwood equation, from which the rate constants k and apparent adsorption constants K were evaluated. These parameters were employed to optimize a kinetic model which considers appearance and disappearance of all intermediates, as if they were represented by a hypothetical single molecule. By this way, two couples of parameters, k(1) and K(1), k(2) and K(2) were obtained, relative to the two successive steps of the model (substrate disappearance and mineralization). Mean quantum yields of organic carbon mineralization reach 75, 71, and 31% for the chlorinated phenols in the order reported above, with respect to their maximum allowable quantum yields. These values are from 3 to 5 times greater than those measured in laboratory-scale experiments thus showing the excellent performance of the pilot-plant employed.
Bibliographic Reference: Article: Chemosphere (1996)
Record Number: 199611184 / Last updated on: 1996-10-28
Original language: en
Available languages: en