Photocatalytic degradation of microcystin-LR using BiVO4photocatalysts under visible light irradiation: modelling by response surface methodology (RSM)

The microcystin-LR (MC-LR) is a potentially dangerous toxin for animals and human health. So, MC-LR removal from the environment by the use of photocatalysts is recommended. Generally, traditional photocatalysts are dependent on UV light and consume high energy and also produce high heat. So, the use of photocatalysts with low-energy consumption, feasible, and reliable properties that activate in the visible light is very important. The aim of the present study was the removal of microcystin-LR (MC-LR) in visible light by synthesised bismuth vanadate (BiVO4) with the hydrothermal method. The BiVO(4)characteristics were determined by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FT-IR) spectra. The Response Surface Methodology (RSM) was used to survey the effects of operating variables such as pH, contact time, and catalyst dose on MC-LR removal. The results showed that the increase of contact time and catalyst dose had a positive effect on enhancing the removal efficiency of MC-LR, but the effect of pH was negative. The maximum removal efficiency of MC-LR at pH = 5, contact time = 180 minutes and catalyst dose = 0.5 g/l was equal to 93.19%. Therefore, BiVO(4)as an innovative photocatalyst had a suitable effect on the MC-LR degradation under visible light.

Automated summary

The synthesis of bismuth vanadate (BiVO4) through hydrothermal method effectively removes microcystin-LR (MC-LR) under visible light. Response Surface Methodology (RSM) analysis reveals that increased contact time and catalyst dose positively enhance the removal efficiency, while pH has a negative effect.