Photocatalytic degradation of methylene blue dye using bismuth oxyiodide from aqueous solutions

Methylene Blue (MB) is an Azo dye with benzene rings, toxic and persistent in the environment. The aim of this study was selected to evaluate photocatalytic removal of MB dye from aqueous solution using BiOI photocatalyst. Characterisation of BiOI was performed using Fourier transform infrared spectroscopy (FTIR), scanning electronic microscopy (SEM) and X-ray diffraction (XRD). A 5-level-5-factor central composite design (CCD) approach-based response surface methodology (RSM) analysis was used to statistically specify the influence of main process variables, namely contact time, dye concentration, pH and BiOI dosage. The highest removal efficiency of MB was obtained 98.5% in optimum conditions (initial concentration: 10 mg/L, pH: 9, contact time: 91.25 min, BiOI dosage: 0.77 g/L). Experimental data were well fitted to pseudo-second order kinetic model (R-2 = 0.989). As a result, BiOI can be applicable for treating industrial wastewater containing dye.