Ground vermiculite as catalyst for the Fenton reaction

Vermiculite was ground for different times (0.5, 1, 20 and 60 min) and used to promote the heterogeneous Fenton like reaction to oxidize the water contaminants ethinylestradiol (EE) and the model dye indigo carmine (IC). Mössbauer, XRD, particle size, SEM, TEM, BET and atomic absorption showed that ground expanded vermiculite (EV) yielded in water highly dispersed microlayer fragments with iron as Fe2 + (30%) and Fe3 + (70%) exposed on the surface. These surface Fe species showed high efficiency to activate H2O2 to oxidize organic molecules in water in a Fenton like reaction at pH near 7. These results were discussed in terms of Fe species immobilized on the surface of the clay mineral fragments which remain exposed during the reaction and active to generate radicals from H2O2.

Figure optionsDownload as PowerPoint slideHighlights
► Ground vermiculite exposed Fe species very active for the Fenton reaction.
► Fe species, on the surface, remained active for the Fenton reaction, even at pH7.
► The ground vermiculite was more active compared to the homogeneous Fenton system.