Short communicationA novel low-cost method for Hg0 removal from flue gas by visible-light-driven BiOX (XÂ =Â Cl, Br, I) photocatalysts

•A novel technique of Hg0 removal by BiOX (X = Cl, Br, I) under fluorescent light was proposed.•BiOBr and BiOI exhibited much higher Hg0 removal performance.•Superoxide radical (O2−) and holes (h+) played key roles in Hg0 removal in the BiOBr system.•I2 might be an important species for higher Hg0 removal in the BiOI system.

BiOX (X = Cl, Br, I) photocatalysts were synthesized by a simple coprecipitation method and were characterized by SEM, TEM, HRTEM, XRD, TG, DRS, PL, and ESR techniques. The photocatalytic activity of Hg0 removal and the effects SO2 and NO were investigated under fluorescent light. The Hg0 removal performance was in the sequence of BiOI > BiOBr > BiOCl. Compared with BiOBr, BiOI showed much excellent SO2 resistance on Hg0 removal. In the BiOBr reaction system, h+ and O2− could play key roles in Hg0 removal, while for BiOI photocatalytic system, I2 might be an important species for higher Hg0 removal.

Graphical abstractDownload full-size image