A novel method of pH-buffered NaClO 2 -NaCl system for NO removal from marine diesel engine

Marine diesel engines produce a lot of exhaust gas (NO, SO 2 ). Based on the situation that wet scrubbing methods have been already applied to ship desulfurization and seawater is easily accessible around the ships, this paper proposed a novel AOP (advanced oxidation process) of NaClO 2 (sodium chlorite) with Cl − (abundant Cl − exist in seawater) to remove NO from the flue gases of marine engines. The buffer capacity of NaAC (sodium acetate), the effect of Cl − concentration, and Cl − promotion mechanism on NO removal were investigated. The result showed that the existence of NaAC in solution could inhibit the rapid decline of the solution pH. The addition of Cl − achieved a remarkable promotion to NO removal at lower NaClO 2 concentration, which was due to the fast generation of ClO 2 from the promotion decomposition of NaClO 2 by Cl − in acidic condition. Then, the thermodynamic and dynamic mechanism of the generation of ClO 2 was intensively analyzed. And the mechanism of NO removal was discussed finally.