New Sustainable, Scalable and One-Step Synthesis of Iron Oxide Nanoparticles by Ion Exchange Process

Abstract

This work introduces an innovative, sustainable, and scalable synthesis of iron oxides nanoparticles (NPs) in aqueous suspension. The method, based on ion exchange process, consists of a one-step procedure, time and energy saving, operating in water and at room temperature, by cheap and renewable reagents. The influence of both oxidation state of the initial reagent and reaction atmosphere is considered. Three kinds of iron nanostructured compounds are obtained (2-lines ferrihydrite; layered-structure iron oxyhydroxide δ-FeOOH; and cubic magnetite), in turn used as precursors to obtain hematite and maghemite NPs. All the produced NPs are characterized by a high purity, small particles dimensions (from 2 to 50 nm), and high specific surface area values up to 420 m2/g, with yields of production >90%. In particular, among the most common iron oxide NPs, we obtained cubic magnetite NPs at room temperature, characterized by particle dimensions of about 6 nm and a surface area of 170 m2/g. We also obtained hematite NPs at very low temperature conditions (that is 2 h at 200 °C), characterized by particles dimensions of about 5 nm with a surface area value of 200 m2/g. The obtained results underline the strength of the synthetic method to provide a new, sustainable, tunable, and scalable high-quality production.

Surface Coverage Simulation and 3D Plotting of Main Process Parameters for Molybdenum and Vanadium Adsorption onto Ferrihydrite

“…The microscopic investigations showed that the ferrihydrite formed aggregates made of poorly ordered ferrihydrite nanoparticles (ca. 5 nm in size), results that are in accordance with other literature findings [ 41 , 43 , 46 , 47 , 48 , 49 ].…”

New Eco-Friendly and Low-Energy Synthesis to Produce ZnO Nanoparticles for Real-World Scale Applications

“…In fact, interpolating the experimental data provided the fundamental information that the simonkolleite logarithmic decrease (R 2 = 0.9883) was directly related to the symmetric ZnO increase (R 2 = 0.9883), according to the following equations: These results, together with CC values reported in Table 1, are evidence of the novelty and originality of this synthesis, reported for the first time here. In principle, we expected that the fast decrease in chlorides, which occurred at the beginning of the exchange reaction, corresponded to their absorption on the surface of the anionic exchange resin [44,[49][50][51][52], as described by the following formula:…”

“…After 90 min, we stopped the reaction and separated the resin from the produced aqueous suspension using a metallic sieve (180 µm aperture). Next, we placed the exhausted resin in a column, and an 8% wt NaOH aqueous solution was applied at a flow rate of approximately 1 L/min until the resin was completely regenerated and ready for use in a new synthesis cycle [44].…”

Advances in Engineered Metal Oxide Thin Films by Low-Cost, Solution-Based Techniques for Green Hydrogen Production

“…Due to the water viscosity and the high ionic strength, hydrolysis reactions are favored without any catalyst. Traditionally, this effect is more pronounced closer to the critical point of water (374 • C and 22.1 MPa) [85][86][87].…”