Synergistic catalytic effect of iron metallic glass particles in direct blue dye degradation

We report on the high catalytic activity of iron based metallic glass (MG) particles in dissociating direct blue dye (C32H20N6Na4O14S4) (DBD), a toxic water pollutant. We adopted high speed mechanical milling to activate the FeMG particles (of nominal composition Fe48Cr15Mo14Y2C15B6) and optimized the morphology and the particle size to achieve complete degradation of DBD in less than 20 min. The surface morphology and the particle size of the activated particles were characterized using scanning electron microscopy and transmission electron microscopy. They were found to have corrugated edge like catalytically active surfaces after mechanical activation. The dye degradation rate of the activated MG powder was characterized via UV-visible absorption spectroscopy. The rate of dye degradation was significantly faster for the activated particles (within 20 min), compared to both pristine FeMG particles as well as elemental iron particles. In addition, the dye degradation mechanism was studied using Raman and infrared spectroscopy. The catalytically activated surfaces are believed to break the -C-H-, -C-N-, and -N=N- bonds, resulting in complete degradation of DBD.