In this study, we have developed a novel and simple method to prepare Fe/FeS core‐shell nanoparticles using thioacetamide. The Fe/FeS nanoparticles were characterized by X‐ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) in conjunction with EDX analysis. The performance of Fe/FeS nanoparticles was evaluated as catalyst to activate molecular oxygen for Rhodamine B (RhB) removal in aqueous solution. The Fe/FeS nanoparticles shows a much higher reactivity on the activation of molecular oxygen than the pure Fe nanoparticles. A complete set of control experiments were conducted to optimize the reaction conditions, including the dosage of Fe/FeS nanoparticles, the RhB concentration, as well as the initial pH value. Moreover, the free radical quenching studies indicated the generation of the reactive oxygen species, namely hydroxyl radicals (•OH) and superoxide radical anions ( O2•−), and •OH is the predominant one in Fe/FeS‐activated molecular oxygen system. The study reveals that Fe/FeS nanoparticles are a promising candidate for the efficient removal of pollutants. © 2016 American Institute of Chemical Engineers Environ Prog, 35: 1673–1678, 2016

In this study, the PANI‐supported nanoscale zero‐valent iron (PANI/nZVI) composites have been successfully synthesized to remove Rhodamine B (RhB) from aqueous solutions using a heterogeneous Fenton‐like system. The synthetic PANI/nZVI composites were characterized using X‐ray diffraction (XRD), Transmission electron microscope (TEM) and Fourier transform infrared (FTIR). The results showed that they were lamellar structures and nZVI nanoparticles were introduced into their structures. The performances of PANI/nZVI composites on the activation of molecular oxygen for removal of RhB were investigated and the effects of operating parameters, such as PANI/nZVI dosage, PANI and nZVI mass ratio, RhB initial concentration, and pH value on RhB removal were also discussed. The results indicate that PANI/nZVI was proved to be the most efficient in that more than 83.31% of RhB was removed, whereas only 11.15% when using nZVI after reacting for 120 min with an initial RhB concentration of 0.02 mmol L−1 (pH = 6.50). Furthermore, the reaction mechanism was discussed by measuring the concentrations of Fe(II), total Fe and H2O2 formed in the system and examining scavenging effects using copper chloride and methanol. Finally, the stability of PANI/nZVI nanocatalyst was studied. © 2015 American Institute of Chemical Engineers Environ Prog, 35: 48–55, 2016