Degradation of phenol in mine waters using hydrogen peroxide and commercial steel wool

•The degradation of phenol by H2O2 + steel wool has been investigated.•Reaction rate is highly dependent on initial pH of water to be treated. Ideally pH < 7.•120 min for [phenol] reduction from 200 mg/L to 0.5 mg/L in batch reaction•Process is simple to operate and may be used for treatment of coal mine waters and wastewaters.

The present work describes the use of zero-valent Fe in the form of commercial steel wool as a possible catalyst in the hydrogen peroxide oxidation of phenol in waters. The process was studied as a set of batch experiments on a bench scale, simulating the treatment of a contaminated mine water or wastewater from a coal beneficiation operation with an initial phenol concentration extended to 200 mg/L. The effects of the following variables were studied: pH (5 to 9); steel wool mass ratio per volume of effluent (1 g/L to 7 g/L); hydrogen peroxide concentration (1 g/L to 3 g/L) and temperature (25 °C to 45 °C). The best experimental conditions studied led to a reduction of phenol concentration from 200 mg/L to less than 0.5 mg/L in 120 min reaction time.