Insight into the effect of structural characteristics of magnetic ZrO2/Fe3O4 nanocomposites on phosphate removal in water

Abstract

ZrO2/Fe3O4 nanocomposites with magnetic properties were prepared by facile one-step coprecipitation. The different structures of synthesized nanomaterials were obtained by calcination in air at different temperature. The relationship between the structure properties of as-synthesized samples and their adsorption capacities for phosphate has also been explored in detail. Results indicate that amorphous magnetic ZrO2/Fe3O4 has a higher specific surface area, surface hydroxyl and saturation magnetization than that of ZrO2/Fe3O4 nanocomposites with a certain crystalline structure. The calcination temperature of the samples has not significant influence on the isoelectric point of synthesized materials. As-synthesized amorphous magnetic ZrO2/Fe3O4 has a phosphate adsorption capacity of 29.5 mg P/g at near neutral natural pH, which is higher than that of reported in most of literature. The adsorption capacity of adsorbent for phosphate is closely related to its specific surface area and surface hydroxyl. With the increase of calcination temperature, some parameters of prepared magnetic ZrO2/Fe3O4 nanocomposites decreased, such as the specific surface area, surface hydroxyl, saturation magnetization and the adsorption capacity to phosphate. However, the magnetic ZrO2/Fe3O4 nanomaterials have better repeatability for phosphate adsorption. At the same time, the adsorption of phosphate by magnetic ZrO2/Fe3O4 nanomaterials was also studied from the aspect of kinetics.