Oxidation Removal of Nitric Oxide from Flue Gas Using UV Photolysis of Aqueous Hypochlorite.

The oxidation removal of nitric oxide (NO) from flue gas using UV photolysis of aqueous hypochlorite (Ca(ClO)2 and NaClO) in a photochemical spraying reactor was studied. The key parameters (e.g., light intensity, hypochlorite concentration, solution temperature, solution pH, and concentration of NO, SO2, O2, and CO2), mechanism and kinetics of NO oxidation removal were investigated. The results demonstrate that UV and hypochlorite have a significant synergistic role for promoting the production of hydroxyl radicals (·OH) and enhancing NO removal. NO removal was enhanced with the increase of light intensity, hypochlorite concentration, or O2 concentration but was inhibited with the increase of NO or CO2 concentration. Solution temperature, solution pH, and SO2 concentration have double the effect on NO removal. NO is oxidized by ·OH and hypochlorite, and ·OH plays a key role in NO oxidation removal. The rate equation and kinetic parameters of NO oxidation removal were also obtained, which can provide an important theoretical basis for studying the numerical simulation of NO absorption process and the amplification design of the reactor.