Phenol degradation by Fenton-like process.

The main objective of this study was to investigate the optimum conditions for the Fenton-like process on phenol degradation, using Mn(2+) as a supporting catalyst in the Fenton reaction. The effect of the independent factors [H2O2], [Fe(2+)], [Mn(2+)] and t (reaction time) was evaluated on the efficiency of phenol degradation at two pHs (3 and 5). The experimental arrangement adopted was the Box-Behnken delineation, with the phenol concentration after the treatments suggested as response variable. At less acidic pH (5), regardless of [Mn(2+)], it was observed that the conventional Fenton process was the most efficient alternative, considering the optimum condition: 2.65 mmol L(-1) for [H2O2], 0.36 mmol L(-1) for [Fe(2+)], and 90 min for t. It was observed that the addition of Mn(2+) helped the phenol degradation at more acidic pH (3), obtaining the optimum condition: 6.17 mmol L(-1) for [H2O2], 0.36 mmol L(-1) for [Fe(2+)], 1.09 mmol L(-1) for [Mn(2+)], and 90 min for t.