Photocatalytic degradation of rhodamine B by bamboo leaf biochar doped with BiOBrxCl1-x under visible light

BiOBrxCl1-x photocatalysts with different ratios of Br and Cl were synthesized by a coprecipitation method, which were mixed with bamboo leaf biochar with different mass to prepare composite photocatalyst. The materials were characterized by scanning electron microscope, X-ray diffractometer, Fourier transform infrared spectrometer, UV-visible diffuse-reflectance spectra and Zeta potential. The results indicated that 100 mg bamboo leaf biochar doped BiOBr0.2Cl0.8 showed the best photocatalytic performance, which could degrade 96.1% of 10 mg.L-1 rhodamine B (RhB) solution in 100 min, and the mineralization rate of RhB reached 59.6% after 120 min illumination. The effects of catalyst dosage and pH of solution on the degradation of RhB under visible light were investigated. Based on the radical trapping experiment and electron paramagnetic resonance, it can be concluded that the main active species in the degradation process were center dot O-2(-) and h(+). The doping of biochar can reduce the band gap of photocatalyst, increase the light absorption range, construct an electron transmission channel and hinder the photo-generated electron-hole recombination, then improve the photocatalytic efficiency.