Study on 4-bromophenol degradation using wet oxidation in-situ liquid ferrate(Ⅵ) in the aqueous phase

摘要

The study on 4-bromophenol (4-BP) removal using wet oxidation in-situ liquid ferrate(VI) has been conducted. The effects of pH, ferrate(VI) dose, 4-BP initial concentration and temperature on the 4-bromophenol degradation were investigated. In the various pH conditions, 4-BP has the highest removal efficiency in the neutral condition (pH = 6.8). A removal efficiency of 65.79% has been observed after a reaction period of 30 s, and 84.1% after a reaction period of 10 min. A ferrate(VI) dose of 0.467 mM was sufficient to remove most of the 4-bromophenol with the efficiency of 96.71% and k(app) value of 1596 M-1s-1. Increasing the molar ratio ([ ferrate(VI)]/[ 4-BP]) enhanced the reaction rate of 4-BP removal. However, the reaction rate decreased when the molar ratio was more than 140: 1. The optimal temperature has been observed at 25 degrees C. The activation energy obtained was 29.25 kJ/mol. The 4-BP degradation was proposed through an oxidative pathway which involves the formation of phenoxy radical with isobutyraldehyde as the non-aromatic degradation product.