Modelisation and optimisation of the photodegradation of 4-methylphenol in a recirculating batch reactor using UV/ZnO
The study of the photodegradation of 4-methylphenol was carried out in a recirculating pilot plant. This compound is present in the liquid processing waste of the poultry industry. This work consisted of the optimization and the modelling of the elimination of 4-methylphenol by photocatalysis in the presence of ZnO. The use of a design of experiments (DOE) approach, and in particular the response surface methodology (RSM) and a central composite design (CCD), allowed the determination of the influence of the simultaneous effects and the interaction of the operational parameters on the degree of photodegradation. The studied parameters were the initial concentration of 4-methylphenol, the catalyst concentration and the solution recirculation flow. The RSM application made it possible to describe the influence of these three experimental parameters on the effectiveness of the treatment. The optimal parameter values leading to maximum efficiency (100%) were determined. The second-order models obtained for the degradation output and the reduction of COD were validated using various statistical approaches. The use of an ANOVA method showed that the models were highly significant and in good agreement with the experimental results.