Photocatalytic degradation of terbuthylazine: Modelling of a batch recirculating device

Abstract

Abstract A thin layer photocatalyst using chitosan to immobilize TiO2 on a glass fiber woven roving material was successfully used for photocatalytic degradation of terbuthylazine, s model s-triazine herbicide. The reaction was conducted in a photocatalytic recirculating reactor with the photocatalyst inserted as a removable module. The experimental reaction system employed in this study was composed of an annular photoreactor with the immobilized TiO2/chitosan layer and the radiation source and the second part of the reaction system only used for the aeration or the reaction mixture, both operating in unsteady conditions. The kinetic model is based on a simplified consecutive degradation of terbuthylazine to cyanuric acid through intermediate products. The model of the annular reactor is represented by a hyperbolic partial differential equation solved by method of characteristics; the model of the aeration vessel is given by an ordinary differential equation. The proposed model represents a simple way to describe a complex recirculating reactor system operating in unsteady conditions.