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.
Highlights
We studied the synthesized NPs, in terms of structure, crystallinity, morphology, size dimensions, and specific surface area by using several techniques, such as X-ray diffraction (XRD), transmission and scanning electron microscopy (TEM, SEM), atomic
The obtained values denote a reagents consumption > 96% in the first minute of the exchange process, which saturates at values higher than 99% after only 10 min, denoting a very fast reaction and residual chloride contents (RCC) values of about 20–30 mg/L
Groups with chlorides ions (Cl− ) on the resin substrate is extremely fast, and the process completes within 10 min, with a reduction in the chloride content always higher than
Summary
Among the transition metal oxides, iron oxides nanoparticles (NPs) are of technological and scientific importance because their relevant properties are size-dependent. Their variety gives rise to a plethora of possible applications in different fields: from sensors and devices to medical diagnostic and treatments strategies, batteries, and catalysis, as well as in environmental remediation. The application areas of magnetite and maghemite NPs include medical applications (magnetic resonance imaging, antitumoral and hyperthermia), magnetic recording, and magnetic data storage devices; hematite NPs find application in lithium ion batteries, catalysis, coatings, gas sensors, transparent pigments, toners for Nanomaterials 2021, 11, 798.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
