Photodegradation of azo dyes by advanced oxidation process using magnetic composites including titania supported by graphene oxide: a statistical analysis study

Abstract

Advanced oxidation process using magnetic graphene oxide decorated with variable content of titania nanoparticles (labeled as MGO@TiO₂#1 and MGO@TiO₂#2) is used as an effective technique for photo disintegration of methyl orange as an azo dye from industrial wastewater. The efficacy of time, pH, and interaction of them on disappearance rate is reported. The results found show that the rate of degradation is significantly affected by the time and increases significantly with it enhance. The dependence of the rate of methyl orange degradation on pH indicates a change in the trend with increasing pH. As the pH enhances from the acidic to neutral zone (from pH = 3 to pH = 7), the decomposition rate decreases, and after increasing to the alkaline zone (pH = 11), an enhancing trend is achieved. Such a behavioral change is related to the difference in the number of free ions in acidic and alkaline suspensions. Comparing the effect of the two synthesized photocatalysts on the rate of breaking of azo dye bonds indicates that MGO@TiO₂#2 has greater power in increasing degradation, which can be attributed to its higher content of photocatalytic nanoparticles compared to MGO@TiO₂#1. Statistical studies of the results using analysis of variance confirm the significant effect of experimental parameters on the rate of degradation. Therefore, statistical models consist of only individual parameters and their interactivity that have a notable efficacy. The proposed models are capable of estimating alterations in the yield of degradation with regard to effective factors at a 95% confidence level.