Degradation Mechanism of Methyl Orange Dye Using Fe/Ag/Zn Trimetallic Nanoparticles

The present study involves the synthesis of polyvinylpyrrolidone (PVP)-stabilized iron-based trimetallic nanoparticles with different metal addition sequences (Fe/Ag/Zn, Fe/Zn/Ag and Fe/(Zn/Ag)) using the sodium borohydride reduction method. In order to investigate the catalytic reactivity of the nanoparticles, a series of batch experiments were performed using methyl orange dye as a model pollutant. It was found that the Fe/Ag/Zn 5:0.1:5 system showed a maximum catalytic activity compared to the other studied trimetallic systems. About 100% of the methyl orange dye was degraded within 1 min and the second-order rate constant obtained was 0.0744 (mg/L)-1min-1; the rate of reaction was higher than that of the other trimetallic systems. Furthermore, the effects of pH, initial dye concentration and nanoparticle dosage on the degradation of methyl orange were investigated. The results showed that the reactivity of the Fe/Ag/Zn trimetallic nanoparticles was highly dependent on the aforementioned parameters. Higher reactivity was obtained at lower pH, lower initial methyl orange dye concentration and higher nanoparticle dosage. Lastly, liquid chromatography-mass spectroscopy (LC-MS) was used to elucidate the reaction pathway and identify by-products from methyl orange degradation. The degradation of methyl orange dye using Fe/Ag/Zn trimetallic nanoparticles was rapid; the nanoparticles proved to be effective at degrading methyl orange and can be used to remediate azo-dye wastewater from textile industries.