Zinc doping of superparamagnetic iron oxide nanoparticles coated with an ionic derivative of chitosan significantly improves their properties for magnetic hyperthermia.

Zinc ferrite nanoparticles were obtained by chemical methods (co-precipitation and thermal decomposition of metalorganic compounds) and systematically probed with volume (XRD, VSM), microscopic (TEM) and element sensitive probes (ICP-OES, Mössbauer Spectroscopy, XPS, XAFS). Magnetic studies proved the paramagnetic response of stoichiometric ZnFe2O4 (ZF) nanoparticles, while superparamagnetic behavior was observed in as-synthesized, non-stoichiometric ZnxFe3−xO (NZF) nanoparticles. Upon annealing up to 1400 °C in an inert atmosphere, a significant change in the saturation magnetization of NZF nanoparticles was observed, which rose from approximately 50 up to 140 emu/g. We attribute this effect to the redistribution of cations in the spinel lattice and reduction of Fe3+ to Fe2+ during high-temperature treatment. Iron reduction is observed in both ZF and NZF nanoparticles, and it is related to the decomposition of zinc ferrite and associated sublimation of zinc oxide.

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According to the International Energy Agency, biorefinery is “the sustainable processing of biomass into a spectrum of marketable bio-based products (chemicals, materials) and bioenergy (fuels, power, heat)”. In this review, we survey how the biorefinery approach can be applied to highly porous and nanostructured materials, namely aerogels. Historically, aerogels were first developed using inorganic matter. Subsequently, synthetic polymers were also employed. At the beginning of the 21st century, new aerogels were created based on biomass. Which sources of biomass can be used to make aerogels and how? This review answers these questions, paying special attention to bio-aerogels’ environmental and biomedical applications. The article is a result of fruitful exchanges in the frame of the European project COST Action “CA 18125 AERoGELS: Advanced Engineering and Research of aeroGels for Environment and Life Sciences”.