Statistical optimization of process conditions for photocatalytic degradation of phenol with bismuth molybdate photocatalyst

In this study, a visible light active photocatalyst bismuth molybdate was prepared by the chemical precipitation method. It was characterized using different instrumental techniques such as scanning electron microscope, Fourier transforms infrared spectroscopy, UV–visible spectroscopy (UV–Vis), and X-ray diffraction. The bandgap energy of the photocatalyst was found to be 2.84 eV, which showed it is visible light active material. The prepared catalyst was applied for the photo-degradation of a toxic organic pollutant such as phenol in its aqueous solution under the irradiation of visible light. Different operating degradation parameters were optimized and maximum degradation of up to 91.6% has been observed at pH 3 with a 10 mg/L initial concentration of phenol. The degradation was endothermic and the data of phenol degradation was analyzed by design expert software as well as evaluated statistically using the best-optimized conditions for higher degradation efficiency. Moreover, the data were also analyzed by the application of pseudo-first-order and pseudo-second-order-kinetics non-linear least-square fits and fitted best with pseudo-second-order kinetic. Furthermore, A possible mechanism based on the generation of electron–hole for phenol degradation has also been proposed in the present work.