LAUSR

Abstract A series of magnetic Ag/BiOI/ZnFe 2 O 4 hybrids synthesized via hydrothermal process, subsequent deposition-precipitation and photoreduction method were employed to remove elemental mercury (Hg 0 ) under fluorescent light irradiation. The effects of Ag content, fluorescent light irradiation, reaction temperature, pH value, flue gas composition, anions and photocatalyst dosage on Hg 0 removal were investigated in detail. The as-synthesized photocatalysts were characterized using N 2 adsorption-desorption, XRD, SEM, TEM, HRTEM, XPS, VSM, DRS, ESR, PL and photocurrent response. The results showed that the ternary Ag/BiOI/ZnFe 2 O 4 hybrids possessed enhanced visible-light-responsive photocatalytic performances for Hg 0 removal. Ag/BiOI/ZnFe 2 O 4 photocatalyst could be easily recovered from the reaction solution by an extra magnet and was stable in the process of Hg 0 removal. Lower content of Ag was highly dispersed on the surface of BiOI/ZnFe 2 O 4 , while higher content of Ag would result in some aggregations and/or the blockages of micropore. In comparison to BiOI/ZnFe 2 O 4 , Ag deposited BiOI/ZnFe 2 O 4 material showed lower recombination rate of electron–hole pairs. The superior Hg 0 oxidation removal could correspond to good match of BiOI and ZnFe 2 O 4 , excellent fluidity and surface plasmon resonance effect of Ag 0 nanoparticles, which led to higher separation efficiency of photogenerated electrons and holes, thereby enhancing the hybrids’ photocatalytic activity.