Photo-catalytic oxidation reaction of gaseous mercury over titanium dioxide nanoparticle surfaces

Hg0(g) is known to undergo photo-catalytic oxidation by UVA-irradiated TiO2 surfaces. One micrometre layers of TiO2 on quartz glass were irradiated within the 240–800 nm range. Gaseous mercury was measured by mass spectrometry single ion monitoring. The surface configuration and elemental characterization of TiO2 layer was evaluated using scanning electron microcopy with energy dispersive spectroscopy. The LH adsorption constant of was found to be KHg = (5.1 ± 2.4) × 10−14 cm3 and an apparent surface deposition rate of k = (7.4 ± 2.5) × 1014 min−1 cm−2 under experimental conditions. Water did not affect the rate constant. We show TiO2 could be employed to reduce mercury concentrations in gas streams, even at very high Hg0 concentrations.