Chemical oxidation of anthracite with hydrogen peroxide via the Fenton reaction
Solutions of 30% H 2 O 2 ranging from pH = 0 to pH = 11.5 have been used to oxidize anthracite at room temperature. The inorganic impurities, primarily pyrite, catalysed the oxidation and reduction of H 2 O 2 (the Fenton reaction) to form the hydroxyl radical; the oxidation of the organic matter was minimal and was observed only in strong acidic solutions ( pH < 1.5). After acid demineralization, samples of the same anthracite underwent a significant enhancement of oxidation in both acid and alkaline solutions ( pH = 0.4–11.5). As all the iron had been removed from the surface and the reactions were completed in a much shorter time, the oxidation mechanism must have been of a different nature than that for the untreated anthracite. A qualitative model based on the catalytic decomposition of H 2 O 2 by activated carbon sites in the coal surface is used to explain the oxidation of the demineralized anthracite.