Formation of Zero-valent Iron Nanoparticles Mediated by Amino Acids

Abstract

Zero-valent iron nanoparticles (NZVI) which are frequently investigated for their application potential in pollutants removal can be prepared by several different ways. Here, we report NZVI formation by wet chemical synthesis in the presence of selected L-amino acids, thus low-molecular weight and biocompatible species. According to our results based mainly, but not only, on Mössbauer spectroscopy (an excellent iron sensitive method), there are distinct differences in zero-valent iron content when each of the amino acids under study mediated NZVI formation. The content of iron atoms in the oxidation state of zero is one of crucial parameters when considering the reductive mode of NZVI action against pollutants. For instance, while the presence of L-glutamic acid promoted NZVI generation, L- cysteine hindered it completely. The effect of L-arginine and L-glutamine presence during NZVI formation was also investigated and evaluated. Moreover, the influence of acidic and alkaline pH values on NZVI formation in the presence of all four selected L-amino acids was looked into. It turned out that acidic and alkaline pH values have negative effects on NZVI formation in the presence of L-glutamic acid and L-glutamine. On the contrary, almost no effect of pH was observed for L-cysteine and L-arginine.