Self-assembled magnetite peony structures with petal-like nanoslices: one-step synthesis, excellent magnetic and water treatment properties

Abstract

Self-assembled magnetite (Fe 3 O 4 ) peony structures with petal-like nanoslices have been successfully synthesized by a low-temperature and environmentally friendly one-step aqueous method without any surfactant and calcination treatment. Powder X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), Mo ¨ssbauer spectroscopy and superconducting quantum interference device magnetometer measurements were used to characterize the samples. The experimental results indicate that the use of the organic additive triethanolamine (N(CH 2 CH 2 OH) 3 ) has an obvious impact on the morphologies of the products. The possible formation mechanism for the Fe 3 O 4 peony structures with well-defined morphology has been presented in detail. The magnetic and electrical properties of the Fe 3 O 4 peony structures are investigated. The sample shows a ferrimagnetic behaviour with a high saturation magnetization of 88.4 emu g 21 at 295 K. Low-field magnetoresistance of ca. 22.0% is achieved in an applied magnetic field of ¡1.0 T at 295 K. In addition, the as-prepared Fe 3 O 4 peony materials are studied as adsorbents in waste-water treatment, and exhibit an excellent ability to remove Cr(VI) pollutant from aqueous solution. The Fe 3 O 4 peony sample demonstrates ca. 5.24 mg g 21 of adsorption capacity towards Cr(VI) ions favourably comparing with commercial and reported adsorbents.

Biomineralized Multifunctional Magnetite/Carbon Microspheres for Applications in Li‐Ion Batteries and Water Treatment

“…However, the powder did not show any magnetic properties. According to previous reports,40–42 the solution‐based growth of such a 3D hierarchical spherical structure consisting of 2D nanoflakes mainly proceeds in two steps; primary nucleation‐growth and oriented self‐assembly, as observed here. In addition, Wang et al 8.…”

“…More importantly, these magnetite (Fe 3 O 4 ) microspheres have 3D hierarchical structures and flower‐like morphologies. Although flower‐like spheres of iron oxides have been synthesized previously,18, 20, 40–42 the synthesis of these magnetite (Fe 3 O 4 ) structures is unique in that it began from the nucleation and 2D growth of FeO(OH) nanoflakes along the bacterial surfaces, after which the spherulitic surface derived from the template materials transformed into higher‐dimensional microspheres with porous, hollow structures and/or composites with the carbonized bacteria. Furthermore, both the porous 3D hierarchical hollow magnetite (Fe 3 O 4 ) microspheres and the carbon in Fe‐400Ar composite are expected to be advantageous for Li‐ion battery and water purification applications.…”

“…In subsequent cycles, the cathodic and anodic peak potentials shift to approximately 0.75 and 1.85 V, respectively. As for the cathodic process, both the peak intensity and integrated area decrease in the second cycle, indicating that irreversible reactions occurred in the electrode material with an SEI film 40. 43 However, there is no obvious potential change in the anodic peak, suggesting that the electrochemical reaction proceeds to an identical extent.…”

Architectured design of superparamagnetic Fe3O4nanoparticles for application as MRI contrast agents: mastering size and magnetism for enhanced relaxivity

“…In this context and taking into account previous works, 34,[39][40][41] we propose that the alkanolamines coordinate with Fe(II) and Fe(III) cations through their hydroxyl and amine groups. 45 More recently, TEA was used as ligand to iron precursors in the synthesis of Fe 3 O 4 nanoparticles, but the reported procedure still required using NaOH base (NaOH:TEA molar ratio = 36:6) and a Fe(II)/Fe(III) ratio of 1.33, resulting in particles with sizes above 7.8 nm. 40,41 Our results also suggest that among the three alkanolamines, TEA is the most efficient agent for the particle size reduction.…”

Magnetite and Other Fe-Oxide Nanoparticles

“…These characteristic peony-like nanostructures were obtained by a low-temperature one-step aqueous method without any surfactant and calcination treatment [27]. In this case, the authors explain the obtained morphology by considering a self-assembling mechanism, starting from nanocubes and truncated nanocubes, moving to octahedra and finally to the peony structure.…”