Photocatalytic oxidation removal of Hg0 by ternary Ag@AgCl/Ag2CO3 hybrid under fluorescent light

Abstract

Photocatalytic oxidation removal of elemental mercury (Hg0) by Ag@AgCl/Ag2CO3 hybrids was carried out in a wet scrubbing reactor under fluorescent light. The photocatalysts synthesized via a modified coprecipitation method were characterized by using SEM-EDS, HRTEM, N2 adsorption-desorption, XRD, XPS, DRS, and ESR. Effects of operational parameters on Hg0 removal, including AgCl content, fluorescent light (FSL) irradiation, pH value, reaction temperature, and flue gas components (O2, SO2 and NO) were studied in detail. Furthermore, simultaneous removal of Hg0 and SO2 was investigated and the possible mechanism of highly enhanced Hg0 removal efficiency was proposed. The results showed that AgCl amount, fluorescent light irradiation, reaction temperature, SO2 and NO had notable impact on Hg0 removal efficiency. Simultaneous removal efficiencies of 98% for SO2 and 80% for Hg0 were obtained by coupling Ag@AgCl(0.3)/Ag2CO3 with Ca(OH)2 under FSL. The trapping studies of reactive radicals exhibited that holes (h+) were one of the main reactive species for Hg0 removal.