Influence of magnetite nanoparticles surface dissolution, stabilization and functionalization by malonic acid on the catalytic activity, magnetic and electrical properties

Abstract Stabilization and modification of magnetite nanoparticles synthesized by the co-precipitation method were presented in these studies. The role of chemical treatment on the structure and properties of Fe3O4 nanoparticles was described. It was noted, that the functionalization of nanoparticles surface by malonic acid has a negative impact on the catalytic activity in Fenton and photo-Fenton processes. The decolorization rate decreases from 86% to 35% and from 93% to 85.5 % at the same reaction time for these processes, respectively. However, the magnetite nanoparticles stabilized by malonic acid have higher saturation magnetization and electrical conductivity. These changes were related to the removal of the oxidized surface layer and to the stabilization of iron ions by malonic acid molecules, which was confirmed by the analysis of Mossbauer spectra. The proposed modification also allowed to reduce the size of the agglomerated nanoparticles 10 times and to produce stable Fe3O4 NPs.