Application of the Taguchi Experimental Design in the Determination of the Optimal Conditions of the Photocatalytic Degradation Reaction of Sunset Yellow FCF Aazoic Pollutant Using Silver Nanoparticles in a Photoreactor

In this study, silver nanoparticles (Ag-NPs) as catalysts in the photocatalytic degradation reaction of Sunset Yellow FCF (SYF) azo dye in aqueous solution were investigated. Ag-NPs were prepared by using walnut (Juglans regia L.) leaf extract. The synthesis of Ag-NPs has been done using green chemistry, which is an environmentally friendly, low-cost, fast, and safe method. Extraction was done with a facile method, as well as the synthesis of Ag-NPs in a short period and with high efficiency. The Ag-NPs were characterized by Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDS), X-Ray Diffraction (XRD), and Fourier Transform InfraRed (FT-IR) spectroscopy. Optimum conditions for dye degradation were determined using Taguchi experimental design method with (L9(34)) orthogonal array. Analysis of the response of each experiment was based Signal to Noise (S/NL) ratio calculated. The effects of operational parameters such as catalyst amount, pH, irradiation time, and temperature in three levels for each factor were studied. The Taguchi results showed that catalyst amount= 20 mg/l (level 2), pH= 4 (level 1), irradiation time = 45 min. (level 3) and temperature= 30 °C (level 3) was the optimum conditions for this process. The most influence of each factor on the process was determined using the Analysis of Variance (ANOVA) method. The most significant factor in this process was pH. The interaction between pH×catalyst amount was the most influencing interaction. The analysis of primary ANOVA showed that percent (p(%)) parameters were: catalyst amount (12.002%), pH (46.298%), irradiation time (35.311%), and temperature (6.383%). The contribution of factors in this process was found to be in the following order: catalyst amount (0.142), pH (0.431), irradiation time (0.397), and temperature (0.18). A pseudo-first-order kinetic reaction with rate constant k=0.0721 min−1 was observed for dye photocatalytic degradation.