Photocatalytic degradation of methylene blue using ZnO modified with nano-biochar derived from bacterial cellulose

In this study, nanosize-controlled ZnO nanoparticles anchored onto a 3D network structure of carbonized bacterial cellulose (ZnO@CBC) composites were synthesized and evaluated for the removal of methylene blue (MB). Characterization of the ZnO@CBC photocatalyst was conducted using scanning electron microscopy, transmission electron microscopy , X-ray diffraction and UV–Vis diffuse reflection spectrometer. The effects of various parameters, such as initial pH, photocatalyst dosage, initial MB concentration, and water matrix, on the photocatalytic activity were investigated. The optimal ZnO@CBC composite with a moderate amount of ZnO (ZnO@CBC-2) exhibited a degradation efficiency of MB as high as 99.6 % under light irradiation for 50 min. Furthermore, the ZnO@CBC-2 photocatalyst demonstrated satisfactory stability over five cycles without significant performance degradation. Radical scavenging experiments indicated that superoxide radical (·O 2− ), hydroxyl radical (·OH), and hole ( h + ) were the primary reactive species in the photocatalytic degradation system. This work introduced a promising methodology for the design of highly efficient photocatalysts with strong adsorption performance, which also expanded the application of carbonized bacterial cellulose in the field of photocatalysis .