Petroleum oxidation using Fenton's reagent over beach sand following a spill

Removal and oxidation of petroleum adhered onto the beach sand after a spill over Guanabara Bay in Rio de Janeiro (Brazil) have been studied using Fenton's reagent (Fe2+ + H2O2). Jar tests were done on 5 and 20 g sand suspended in 200 ml aqueous solution containing iron(II) salt and hydrogen peroxide under constant stirring. The H2O2(g):Fe(g)2+ ratio varied from 0.5:1 to 50:1, pH was 2.0 and 6.0 and reaction time 1 and 3 h. Initially, the contaminated sand content of oil and grease (O&G) was 32 g/kg sand. The statistical analysis showed time and iron-sand and H2O2-iron-sand interactions to be the most significant variables, with an average O&G removal from the contaminated sand being just 30% after 3 h reaction. However, oil was removed from the sand (by up to 97%) and passed to the aqueous phase, making waste final disposal easier. The post-reaction analysis showed the supernatant to be biodegradable. Chromatographic analysis results were that the Fenton's reaction favored both the change and reduction of oil saturated and aromatic fractions.