title: Photocatalytic degradation of two volatile fatty acids in an annular plug-flow reactor; kinetic modeling and contribution of mass transfer rate.
abstract: This study investigates the influence of inlet concentration and of flow rate on the degradation rate of two Volatile Fatty Acids (butyric and propionic acids). TiO2-coated nonwoven fiber textile was used as the photocatalyst in an annular plug-flow reactor at laminar flow regime. The kinetic follows a Langmuir-Hinshelwood form. The oxidation rate increased with the flow rate, which emphasizes the influence of the mass transfer. A first design equation is proposed considering that the mass transfer could be neglected. Despite a good accuracy of the model, the determined kinetic constants are dependent on the flow rate which highlights the contribution of the mass transfer rate on the global degradation rate. Thus, a new design equation which includes the mass transfer rate was developed. Using this model, the degradation rate can be determined for any given flow rate. Moreover, it allows the estimation of the contribution of mass transfer and chemical reaction steps at given experimental conditions; and thus providing an interesting tool for reactor optimization or design.
authors.affiliation: Sciences Chimiques de Rennes, UMR 6226, CNRS-ENSCR, Equipe Chimie et Ingénierie des Procédés, Ecole Nationale Supérieure de Chimie de Rennes, avenue du Géngral Leclerc, 35700 Rennes, France.
authors.forename: Pierre-François
authors.initials: PF
authors.lastname: Biard
authors.forename: Abdelkrim
authors.initials: A
authors.lastname: Bouzaza
authors.forename: Dominique
authors.initials: D
authors.lastname: Wolbert
mesh_terms: D000397:Air Pollution / Q000517:prevention & control; D005232:Fatty Acids, Volatile / Q000737:chemistry*; D007700:Kinetics; D010782:Photolysis
chemical_list: D005232:Fatty Acids, Volatile