Removal of Hg0 from containing‐SO2/NO flue gas by ultraviolet/H2O2 process in a novel photochemical reactor

Abstract

A novel photochemical spray reactor is first developed and is used to remove Hg0 and simultaneously remove Hg0/SO2/NO from flue gas by ultraviolet (UV)/H2O2 process. The effects of several parameters (UV wavelength, UV power, H2O2 concentration, Hg0 inlet concentration, solution temperature, liquid–gas ratio, solution pH, SO2 concentration, NO concentration, and O2 concentration) on removal of Hg0 by UV/H2O2 process were investigated. Removal mechanism of Hg0 is proposed and simultaneous removal of Hg0, NO, and SO2 is also studied. The results show that the parameters, UV wavelength, UV power, H2O2 concentration, liquid–gas ratio, solution pH, and O2 concentration, have significant impact on removal of Hg0. However, the parameters, Hg0 inlet concentration, solution temperature, SO2 concentration, and NO concentration, only have small effect on removal of Hg0. Hg2+ is the final product of Hg0 removal, and Hg0 is mainly removed by oxidations of H2O2, ·OH, · O, O3, and photoexcitation of UV. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2275–2285, 2014