Optimization of photocatalytic degradation of naphthalene using nano-TiO2/UV system: statistical analysis by a response surface methodology

In this study, the response surface methodology (RSM) was applied for modeling and optimization of photocatalytic degradation of naphthalene using TiO2 nanoparticles in a batch slurry system. The effect of four independent parameters such as agitation speed (X-1), air flow rate (X-2), catalyst loading (X-3), UV light intensity (X-4), and their interactions was investigated. A quadratic model was qualified to predict the degradation percent of naphthalene in different conditions, consequently. The significance of independent variables and their interactions were evaluated by the analysis of variance (ANOVA). Evaluation of the p-value approved that the effect of interactions is not very significant and so interaction terms were removed from the initial model. In order to achieve the maximum degradation percent, the optimum conditions were obtained by mathematical and statistical methods. The results showed that the maximum degradation efficiency can be achieved at the optimum conditions: X-1=150rpm, X-2=5L/h, X-3=2.17g/L, and X-4=18.67W. The good agreement between the predictive and experimental results at the optimum point verified the model adequacy and validity of the obtained optimum conditions.