Catalytic oxidation of o-chloroaniline in hot compressed water: Degradation behaviors and nitrogen transformation

Catalytic oxidation of o -chloroaniline ( o- ClA) in hot compressed water (HCW) was investigated in a fused quartz tube reactor (FQTR) to determine the effects of catalyst, temperature, oxygen stoichiometric ratio (OSR) and reaction time on o- ClA mineralization, total nitrogen (TN) removal rate and nitrogen-containing products distribution. The results showed that o -ClA can be effectively degraded in HCW. With the increased of OSR, retention time and temperature or added of Mn 2 O 3 as catalyst, the mineralization rate of o -ClA and the removal rate of TN increased. Ammonia-N was the main nitrogen-containing intermediate product of o -ClA degradation, however, when the oxidant was excessive, ammonia-N was oxidized to form nitrate-N. Althought the catalytic effect of Mn 2 O 3 on the mineralization of o -ClA was not outstanding, it promoted the removal of ammonia-N from the benzene ring, improved the degradtion of ammonia-N, and inhibited the production of nitrate-N. GC–MS analyzed results indicated that o -chlorophenol was the main degradation intermediate product of o -ClA in HCWO process. Meanwhile, the potential degradation pathway of o -ClA was proposed. This work thus provides basic knowledge about o -ClA catalytic oxidation removal in HCW process.