Abstract:

The simultaneous wet air oxidation of nitrobenzene (NB) and phenol with homogenous catalyst was carried out in a stainless autoclave in a temperature range of 150-210 ℃ and at a partial oxygen pressure of 1.0 MPa. Compared with the non-catalytic co-oxidation of NB and phenol, the presence of the homogeneous catalyst greatly improved the conversion of both compounds. The transition metal ions Cu²⁺, Co²⁺ and Ni²⁺ were found to be effective catalysts, with Cu²⁺ affording the best results. How phenol was added to the autoclave was investigated and was found to affect the conversion of NB. Adding phenol in smaller portions can help to degrade NB more effectively. As an example, two additions of phenol with Cu²⁺ as the homogenous catalyst allowed 95% conversion of NB at 200 ℃ in 1 h. This catalytic co-oxidation method incorporating the addition of phenol initiator batches therefore provides an alternative and effective means of removing persistent organic pollutants from the environment.

Key words: Catalytic wet air oxidation, Co-oxidation, Homogenous catalyst, Advanced oxidation process, Wastewater treatment