[Catalytic wet air oxidation of phenol and aniline over multi-walled carbon nanotubes]

Multi-walled carbon nanotubes (MWNTs) without any metal ions were used as the catalyst, and investigated in the CWAO of phenol and aniline in a batch reactor. The structures of the MWNTs were characterized by means of SEM and TEM. It showed that the MWNTs, treated with the mixed acid (HNO3-H2SO4), displayed excellent activity and stability in the CWAO. Under the reaction temperature of 160 degrees C, the total pressure of 2.5 MPa, the initial concentration of 1000 mg/L and loading the catalyst of 1.6 g/L, 100% phenol and 86% COD were removed after 120 min reaction in CWAO of phenol. At the same operating conditions, 83% aniline and 68% COD removals were obtained in the CWAO of aniline solution when the initial concentration of aniline was 2 000 mg/L. The surface functional groups played the important role for the high activity of the MWNTs in CWAO of organic compounds.