Catalysts Prepared with Matured Compost Derived from Mechanical-Biological Treatment Plants for the Wet Peroxide Oxidation of Pollutants with Different Lipophilicity

Abstract

The current work proposes a strategy for the valorization of compost obtained from municipal solid waste, through its activation with H2SO4 and thermal treatment at 400–800 °C to produce low-cost catalysts for wet peroxide oxidation. All the developed materials were catalytically active for the aqueous solution oxidation of 2-nitrophenol (C2-NP,0 = 0.5 g L−1) and 4-nitrophenol (C4-NP,0 = 5.0 g L−1). In particular, using the catalysts prepared by thermal activation of the compost (with and without subsequent treatment with H2SO4), complete removal of both model pollutants was achieved after 24 h (at 50 °C, initial pH 3, Ccat = 2.5 g L−1, and employing a stoichiometric quantity of H2O2 needed for the total mineralization of the pollutants). In a cyclohexane–water mixture (simulating biphasic oily wastewater), 4-nitrophenol is also completely removed by the catalyst not treated with H2SO4. In contrast, the removal of 2-nitrophenol decreased to 93% due to its higher lipophilic character. Thus, this work demonstrates that active catalysts for wet peroxide oxidation can be obtained by using as a precursor a matured compost derived from municipal solid waste.