Oxidative Absorption of NO by Sodium Persulfate Coupled with Fe2+, Fe3O4, and H2O2

The oxidative absorption of nitric oxide (NO) by sodium persulfate (Na2S2O8) coupled with Fe2+, Fe3O4, and H2O2 was investigated in a bubble column reactor. Moreover, the effect of temperature on NO removal has been studied. At high temperatures, Fe2+ and Fe3O4 could effectively activate persulfate to form sulfate radicals, leading to high removal efficiency of NO. About 62% and 86% of NO were removed at 75 and 90 degrees C, respectively. Also, the optimum Fe2+ concentration for 0.2 mol L-1 persulfate was 1.0 mmol L-1 at 75 degrees C, under which the removal efficiency of NO was observed to be 89%. However, beyond 1.0 mmol L-1 Fe2+, the increase in Fe(2+)concentration was unfavorable to NO removal due to the scavenging of radicals by the excess Fe2+. Additionally, the presence of 2.85 mmol L-1 Fe3O4 increased the NO removal efficiency by 11% compared to that obtained in the absence of Fe3O4. It was proposed that activation ability of Fe3O4 to persulfate was attributed to Fe2+ on the Fe3O4 surface. Moreover, the addition of H2O2 led to the increase of the NO removal for some time, but followed by a drop because of the depletion of H2O2. It was suggested that H2O2 served as an oxidant rather than an activator of persulfate. (c) 2014 American Institute of Chemical Engineers Environ Prog, 2014 (c) 2014 American Institute of Chemical Engineers Environ Prog, 34: 117-124, 2015