Photocatalytic activity of PVA-CeO 2 -biochar composites for effective removal of methylene blue from wastewater

Abstract This article examines the removal of methylene blue, used as an indicator or tracer, from mining wastewater. Particular attention is given to the use of new composite photocatalysts. PVA-CeO 2 -biochar composites were synthesized using a two-step combined method. The composites were characterized by X-ray diffraction, scanning electron microscopy, and UV-visible absorption. The results of the photocatalytic properties study showed that the degradation rate of methylene blue was 93–98% after 20 minutes of exposure to UV radiation. The degradation reaction of methylene blue obeys a pseudo-first-order reaction. The reaction rate constant is 0.058 min −1 for PVA/CeO 2 -biochar composites, 0.04 min −1 for PVA/CeO 2 -biochar and is maximum for composites with high biochar content for solutions with MB concentration of 15.2 μmol/L.