Long-lasting activity of Fe0-C internal microelectrolysis-Fenton system assisted by Fe@C-montmorillonites nanocomposites

Core/shell type Fe-0@carbon (Fe@C) nanocomposites inserted in the interlayer space of montmorillonites (MMT) is prepared by one-step pyrolysis of Fe-metal organic frameworks and MMT. Fe@C-MMT serves as Fenton-like catalyst to degrade organic pollutants based on internal microelectrolysis (IME)-Fenton reactions. The MMT coat accelerates galvanic corrosion of Fe-0 to facilitate in-situ generation of Fe2+ and achieves self-regulation of solution pH. Strengthened elimination of phenol and methyl orange with high mineralization efficiency (80%) at initial pH 3-6.5 was achieved in Fe@C-MMT-H2O2 system compared to Fe@C-, ZVI-, and commercial Fe-C-H2O2 systems. The MMT coat retards contact of Fe-0 and Fe(II) species on Fe@C-MMT surface with H2O2, leading to rate-controlling consumption of H2O2 to keep the long-lasting efficiency of the IME-Fenton system. Fe@C-MMT suspension with 10 mM of H2O2 can continuously degrade organic pollutants within 40 h. Fe@C-MMT can be recycled for five times and shows good resistance to oxygen and acid corrosion.