Advanced Oxidative Removal of Nitric Oxide from Flue Gas by Homogeneous Photo‐Fenton in a Photochemical Reactor

Abstract

In this work, advanced oxidation removal of nitric oxide (NO) from flue gas by homogeneous Photo-Fenton was investigated in a photochemical reactor and the effects of several influencing factors on NO removal were evaluated. The gasliquid reaction products were determined. The reaction pathways of NO removal are also preliminarily discussed. It was found that with the increase of Fe 2+ concentration, NO removal efficiency first increased and then decreased. Increasing H 2 O 2 concentration and UV radiation intensity greatly increased NO removal efficiency, but the growth rates gradually became smaller. NO removal efficiency greatly reduced with the increase of gas flow and NO concentration, and only slightly decreased with the increase of solution temperature, but significantly increased with the increase of initial solution pH value. The main anion product in the liquid phase was NO 3 -. With respect to removal of NO using homogeneous Photo-Fenton, ·OH oxidation was the main reaction pathway, and H 2 O 2 oxidation was the secondary reaction pathway.

Removal of Hg0 and simultaneous removal of Hg0/SO2/NO in flue gas using two Fenton-like reagents in a spray reactor

“…This phenomenon may be explained by the several reasons as follows. Related results indicate that H 2 O 2 in alkaline (9) and (10) [1,[23][24][25].…”

“…In addition, related results show that increasing Fe 3+ or Cu 2+ concentration will increase the yield of Å OH produced by Fentonlike reagents by the following reactions (3)-(8) [17][18][19][20][21][22]24,25].…”

“…However, both Å OH and H 2 O 2 can effectively oxidize SO 2 [24][25][26]. Based on the above reactions (3)-(5), it can be seen that the molar ratio of H 2 O 2 to Å OH is 1:1.…”

“…The results show that with SO 2 concentration increasing from 0 to 2500 ppm, Hg 0 removal efficiency markedly decreases from 91.5% to 70.1%, and from 73.6% to 40.3% under catalysis of Fe 3+ and Cu 2+ , respectively. Related results [1,[23][24][25][26] show that …”

“…Furthermore, some results [24][25][26] indicate that a high solution pH will reduce the oxidizing of H 2 O 2 and accelerate the decomposition of H 2 O 2 , thereby further inhibiting Hg 0 removal. Thus under test conditions, with the increase of solution pH, Hg 0 removal efficiencies have a great decrease using Fe 3+ and Cu 2+ as catalysts, respectively.…”