Box-Behnken Experimental Design Method Applied to Optimize Photo-Fenton Degradation of Pharmaceutical Atorvastatin Calcium in Aqueous Solution

Due to the harmful effects on the environment and public health, Atorvastatin calcium (ATO) has to be removed from wastewater using the photo-Fenton process. The novelty of this study is based on the modeling and the optimization of the operating parameters affecting the efficiency of the process by using the Box-Behnken Design (BBD). Operating factors such as pollutant concentration [20-40 mg/L], iron concentration [1-5 mM], and H2O2 concentration [5-10 mM] were investigated to evaluate the Chemical Oxygen Demand (COD) abatement. A mathematical model of pollutant degradation was established using the MODDE 6.0 software and statistical analysis showed good agreement between experimental results and predictive values with an error of less than 5%, which indicates the soundness of the developed model. The results suggested that the most influential factor on the photo-Fenton degradation of the drug was the initial ATO concentration with an effect of (-22.86), the second was the amount of the H2O2 with an effect of (+2.82), the third was the concentration of Fe3+ ions with an effect of (-2.79). The model obtained by BBD corresponding to the best value of the COD abatement rate (100%)   of ATO led to the following optimal conditions: initial concentration of pollutant equal to 20 mg/L, a catalyst concentration equal to 1 mM and a concentration of hydrogen peroxide equal to 10 mM.