Detailed mechanism of organic pollutant oxidation via the heterogeneous Fenton reaction requires using at least two substrates, e.g.: DMSO and EtOH

Heterogeneous catalysts hold immense potential applicability in batch-advanced oxidation technologies. The present study examined LaFeO3 Fenton-like catalyzed oxidation of EtOH and DMSO. LaFeO3 is used to catalyze many processes, including an advanced oxidation process (AOP). Less is known about its role in Fenton-like reactions for AOPs. The results point out that two short-lived oxidizing intermediates are formed. Based on oxidation products analysis, it is tentatively proposed that the two short-lived oxidizing intermediates are [((LaFeIIIO3)n)n((LaFeIIIO2(OH)m-2)(LaFeIV(O)O2)2] and [(LaFeIVO3)2(LaFeIIIO3)n-2]2+. Both substrates are oxidized by [((LaFeIIIO3)n)n((LaFeIIIO2(OH)m-2)(LaFeIV(O)O2)2], the oxidation of DMSO by this intermediate is considerably faster than that of ethanol. [(LaFeIVO3)2(LaFeIIIO3)n-2]2+ oxidizes only EtOH. The yield of [((LaFeIIIO3)n)n((LaFeIIIO2(OH)m-2)(LaFeIV(O)O2)2] is larger than that of [(LaFeIVO3)2(LaFeIIIO3)n-2]2+. The knowledge gained in this study will help elucidate the detailed mechanisms of perovskite catalyzed Fenton-like processes and thus facilitate the development of efficient AOPs. The involvement of two short-lived intermediates was shown only by studying the oxidation of two very different substrates, a novel approach whose ground-breaking results are important for catalytic processes that will advance environmental strategies.