Modeling and optimizing the photo-electro-catalytic degradation of methylene blue by response surface methodology

Abstract

The photo-electrocatalytic system, as one of the advanced oxidation process, was used to degrade Methylene blue (MB), which is commonly existed in textile industries wastewater. In this study, the two-step anodizing method was used to produce titanium nanotube arrays as an anode electrode. Besides, ultra-filtration (UF) was used as a separating membrane between anolyte and catholyte. Response surface methodology as one of the design experiment’s methods was applied to investigate the side effects of MB concentration, pH of anolyte, and density of illumination on MB, turbidity, and color removal percent as well as produced power. To model the responses, quadratic equations were developed and the optimum conditions were investigated to meet 89.3.% desirability which occurred when MB concentration in anode, pH and density of illumination were 16.23 mg/l, 3, and 7.71 W, respectively; which caused MB, turbidity and color removal percent to be 49.92 %, 54.71 %, and 52.08 % respectively, as well as the maximum producing power be 1.026 μw. Model validation was done to calculate the accuracy and precious of mathematical models.