Lignosulfonate-controlled BiOBr/C hollow microsphere photocatalyst for efficient removal of tetracycline and Cr(VI) under visible light

In this study, bismuth oxybromide/carbon (BiOBr/C) visible light catalysts were prepared by using sodium lignosulfonate (SLS) as a surfactant and carbon source to promote the photocatalytic capability of BiOBr. Different amount of SLS was added to regulate the morphology of BiOBr/C. With increasing amount of SLS, the morphology of BiOBr/C was changed from the original flake shape to a microsphere shape, and then self-assembled into a hollow microsphere. The results showed that the as-prepared composites exhibited fairly high removal efficiencies for tetracycline (TC) and hexavalent chromium (Cr(VI)). This was mainly attributed to the variation of morphology and the introduction of carbon, which improved the absorption of light and reduced the band gap for easier separation of photogenerated carriers. Moreover, a possible pathway for the degradation of TC by BiOBr/C was proposed according to the HPLC-MS results. This study provides a novel idea for the application of SLS in the preparation of photocatalysts.