Bismuth oxybromide/bismuth oxyiodide nanojunctions decorated on flexible carbon fiber cloth as easily recyclable photocatalyst for removing various pollutants from wastewater

Various semiconductor powders (such as bismuth oxybromide/bismuth oxyiodide (BiOBr/BiOI) nanojunctions) can photodegrade wastewater efficiently, but their practical application is limited by poor recovery performance. To address the problem, we report the construction of BiOBr/BiOI nanojunctions on flexible carbon fiber cloth (CFC) substrate as an easily recycled photocatalyst by the dipping-solvothermal-dipping-solvothermal four-step method. CFC/BiOBr/BiOI is composed of CFC substate and two layers of nanosheets, while BiOBr nanosheets (thickness: 10-30 nm, diameter: 200-400 nm) were grown in the inner layer and BiOI nanosheets (thickness: 50-80 nm, diameter:300-600 nm) were grown in the outer layer. CFC/BiOBr/BiOI (4 × 4 cm2) can effectively photodegrade 97.7% acid orange 7 (AO7), 91.3% levofloxacin (LVFX) and 97.8% tetracycline (TC) within 120 min under the illumination of visible-light, better than CFC/BiOBr (73.2% AO7, 71.6% LVFX and 81.6% TC). Furthermore, superoxide radical (•O2-) and hydroxyl radical (•OH) are the main active substances during removing LVFX by CFC/BiOBr/BiOI. Besides, CFC/BiOBr/BiOI can efficiently reduce 93.5% chemical oxygen demand (COD) concentration of acrylic resin production wastewater (ARPW) under visible-light illumination for 3 h, better than CFC/BiOBr (36.6% COD). Therefore, CFC/BiOBr/BiOI has broad application prospects in purifying wastewater as a new type of easily recycled photocatalyst.