(708e) Optimization of Ball-Milled Ni/InVO4-TiO2 Photocatalyst for the Degradation of Methyl Orange through Use of An Orthogonal-Array Experimental Design

The effects of various catalyst synthesis parameters on the photocatalytic degradation kinetics of aqueous methyl orange dye are presented. In this study, the four experimental factors investigated were i) InVO4 concentration, ii) nickel concentration, iii) InVO4 calcination temperature, and iv) ball-milling time. Three levels were used for each factor. Due to the large number of possible experiments in a 34 full factorial experiment, an orthogonal-array experimental design was used. Two 15-W UV-A lights were used to degrade 5 ppm (by mass) solutions of methyl orange dye using 1000 ppm of catalyst. Degradation was performed following an initial 1-hr adsorption period. UV-vis spectrophotometry was used to monitor the degradation of the dye. Results indicate that nickel concentration was the dominant parameter, with the relative order of importance of all parameters being nickel concentration > InVO4 concentration > InVO4 calcination temperature > milling time. Results from the orthogonal array design were used to make samples of theoretical ?best? and ?worst? catalysts. Curiously, the predicted worstperforming catalyst was the best-performing overall, though both samples showed substantial improvement over the other samples tested in the orthogonal array.