Factorial Experimental Design for the Optimization of β-Naphthol Photocatalytic Degradation in TiO2 Aqueous Suspension

Abstract

A factorial experimental design was developed to describe the photocatalytic degradation of β-naphthol in a circulating photo-reactor using TiO 2 aqueous suspension. The main and interaction factors studied were the initial concentration of β-naphthol, TiO 2 dosage, pH and circulation flow. The parameters coded as X 1 , X 2 , X 3 and X 4 , consecutively, and were investigated at two levels (−1 and +1). The effects of individual variables and their interaction effects for dependent variables, namely, photocatalytic degradation efficiency (%) were determined. The experimental results and statistical analysis show that increasing in the initial concentration of β-naphthol decreases the photocatalytic degradation efficiency whereas the increase of TiO 2 dosage, pH and the circulation flow have a positive effect on the photocatalytic degradation. The interaction between TiO 2 dosage and circulation flow was the most influencing interaction. However, the interaction between TiO 2 dosage and pH was the least influencing interactions. The variance analysis (ANOVA) was applied and the statistic data showed adequate model.