Naslov
Photocatalytic Degradation of Water Contaminants in Multiple Photoreactors and the Evaluation of Reaction Kinetics Constants Independent of Photon Absorption, Irradiance, Reactor Geometry and Hydrodynamics

Autori
Grčić, Ivana ; Li Puma, Gianluca

Izvornik
Environmental science & technology (0013-936X) 47 (2013), 23; 13702-13711

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
photocatalysis ; photodegradation ; Degussa P25 ; reactor model ; pollutant

Sažetak
The literature on photocatalytic oxidation of water pollutants often reports reaction kinetics constants, which cannot be unraveled from the type of photoreactor and experimental conditions. This study addresses this challenging aspect by presenting a general and simple methodology for the evaluation of fundamental “intrinsic” reaction kinetic constants of photocatalytic degradation of water contaminants, which are independent of photoreactor type, catalyst concentration, irradiance levels and hydrodynamics. The degradation of the model contaminant, oxalic acid (OA) on titanium dioxide (TiO2) aqueous suspensions was monitored in two annular photoreactors (PR1 and PR2). The photoreactors with significantly different geometries, were operated under different hydrodynamic regimes (turbulent batch mode and laminar, flow-through recirculation mode) optical thicknesses, catalyst and OA concentrations and photon irradiances. The local volumetric rate of photon absorption (LVRPA) was evaluated by the six-flux radiation absorption-scattering model (SFM) and further integrated into a comprehensive kinetic model for the adsorption and photodecomposition of OA on TiO2, to determine local reaction rates and, after integration over the reactor volume, the intrinsic reaction kinetics constants. The model could represent the oxidation of OA in both PR1 and PR2 under a wide range of experimental conditions. This study demonstrates a more meaningful way for determining reaction kinetic constants of photocatalytic degradation of water contaminants.

Izvorni jezik
Engleski

Znanstvena područja
Kemija, Kemijsko inženjerstvo, Interdisciplinarne tehničke znanosti

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