Removal of Hg 0 from containing‐SO 2 /NO flue gas by ultraviolet/H 2 O 2 process in a novel photochemical reactor

A novel photochemical spray reactor is first developed and is used to remove Hg 0 and simultaneously remove Hg 0 /SO 2 /NO from flue gas by ultraviolet (UV)/H 2 O 2 process. The effects of several parameters (UV wavelength, UV power, H 2 O 2 concentration, Hg 0 inlet concentration, solution temperature, liquid–gas ratio, solution pH, SO 2 concentration, NO concentration, and O 2 concentration) on removal of Hg 0 by UV/H 2 O 2 process were investigated. Removal mechanism of Hg 0 is proposed and simultaneous removal of Hg 0 , NO, and SO 2 is also studied. The results show that the parameters, UV wavelength, UV power, H 2 O 2 concentration, liquid–gas ratio, solution pH, and O 2 concentration, have significant impact on removal of Hg 0 . However, the parameters, Hg 0 inlet concentration, solution temperature, SO 2 concentration, and NO concentration, only have small effect on removal of Hg 0 . Hg 2+ is the final product of Hg 0 removal, and Hg 0 is mainly removed by oxidations of H 2 O 2 , ·OH, · O, O 3 , and photoexcitation of UV. © 2014 American Institute of Chemical Engineers AIChE J , 60: 2275–2285, 2014