Environmental mineralization of caffeine micro-pollutant by Fe-MFI zeolites.

Environmentally emerging micro-pollutant, caffeine, was mineralized (i.e., full degradation) by the isomorphic incorporation of Fe into silicalite-1 (mordenite framework inverted (MFI) structure zeolite) through a microwave synthesis method. The Fe incorporation conferred mesopore formation that facilitated caffeine access and transport to the MFI zeolite structure. Increasing the Fe content favored the formation of Fe(O) sites within the MFI structure. The catalytic activity for the degradation of caffeine increased as a function of Fe(O) sites via a Fenton-like heterogeneous reaction, otherwise not attainable using Fe-free pure MFI zeolites. Caffeine degradation reached 96% (TOC based) for zeolites containing 2.33% of Fe.