Ceramic nanopowders, aerogels of copper/nickel/cobalt ferrites for use as magnetic photocatalysts

Abstract

The topic of this project is based on the use of an aerogel made from silica (silicon dioxide) combined with spinel ferrite nanoparticles (NPs) that can be used to treat polluted water. The primary ferrite of interest is copper ferrite (CuFe2O4) due to its known photocatalytic capabilities, but cobalt ferrite (CoFe2O4) and nickel ferrite (NiFe2O4) was also investigated. The NPs will be used for the removal of organic pollutants such as dyes using the photocatalytic properties of the ferrites. For this purpose, the interaction between NPs and aerogel can happen in two different ways, the first approach in which the NPs will be pre-synthetized and then mixed / added to the hydrogel, either during hydrogel synthesis or with PVA to the formed aerogel as a composite material. The second method will instead be required to add the materials necessary for the synthesis of the ferrite NPs directly into the silica hydrogel reaction mixture to obtain the final ferrite product in the aerogel after heating . Small amounts of graphene oxide (GO) are also added to some of aerogels for comparison. Overall, it will be necessary to evaluate different aspects during the synthesis to optimize the process. The aerogel will be obtained by a subsequent supercritical drying / freeze-drying / lyophilization step. This type of project require different types of analysis: XRD, SEM, FT-IR and magnetic properties tests to look at ferrite NPs for the analysis of the size, morphology, properties and composition of the different ferrite NPs. Instead for silica aerogel-NPs and silica aerogel-PVA-NPs was used FT-IR and BET to analyze the chemical composition of the sample and porosity and surface area , at the end Uv-Vis was used measure the wavelength of light absorbed from the sample and the band gap, and photocatalytic tests (with visible and UV light) in the liquid phase to monitor the removal of dye (methylene blue) from water.