Eco-friendly synthesis of magnetite (Fe3O4) nanoparticles with tunable size: Dielectric, magnetic, thermal and optical studies

Novel multifunctional RbxWO3@Fe3O4 immobilized Janus membranes for desalination and synergic-photocatalytic water purification

Comparative investigations on ferrite nanocomposites for magnetic hyperthermia applications

The superparamagnetic property of nanomaterials such as Fe3O4 has been considered to be promising for various applications. In this paper, Fe3O4/PPY/CNT nanocomposites were synthesized with utilizing natural iron sand by a coprecipitation method. The as-precipitated Fe3O4 NPs were combined with carbon nanotubes (CNTs) using conductive polypyrrole (PPY) as linking agents. The Fe3O4/PPY/CNT nanocomposites were systematically characterized by FE-SEM, EDS, XRD, BET, and FTIR. Furthermore, the effects of CNTs on magnetic and thermal properties of nanocomposites were investigated by VSM and thermal gravimetric analysis (TGA), respectively. The composites exhibited significant decrease of coercivity value with the content of CNTs increasing. The VSM result confirmed that Fe3O4/PPY/CNT nanocomposites were superparamagnetic. It was found that by increasing the amounts of CNTs, the magnetization of Fe3O4/PPY/CNT nanocomposites gradually decreased. The addition of CNTs is intended to improve the mesoporous property as proved by BET analysis which has the potential application as a nanocatalyst.

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Superparamagnetic Behaviour and Surface Analysis of Fe3O4/PPY/CNT Nanocomposites

Nanosized sorbents for the removal of heavy metal ions are preferred due to high surface area, smaller size, and enhanced reactivity during adsorbate/adsorbent interactions. In the present study, Fe3O4, SnO2, and TiO2 nanoparticles were prepared by microemulsion-assisted precipitation method. The particles were characterized by BET surface area, X-rays diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, transmittance electron microscopy (TEM), and X-ray photoelectron (XPS) spectroscopy. The respective particle sizes calculated from TEM were 7 nm (± 2), 10 nm (± 2), and 20 nm (± 3) for Fe3O4, SnO2, and TiO2. The adsorbents were employed for the adsorption of Pb2+ ions from the aqueous solutions. The respective maximum adsorption capacity for Fe3O4, SnO2, and TiO2 nanoparticles was 53.33, 47.21, and 65.65 mg/g at 313 K. Based on the exchange reaction taking place on the surfaces of Fe3O4, SnO2, and TiO2, it is concluded that Pb2+ ions are adsorbed in hydrated form. The X-ray photoelectron spectroscopy (XPS) studies also support the exchange mechanism and confirmed the presence of elements like Fe, Sn, Ti, Pb, and O and their oxidation states. Both Langmuir and Freundlich models in non-linear form were applied, however, based on RL values, the Langmuir model fits well to the sorption data. Moreover, adsorption parameters were also determined by using non-linear form of the Langmuir model along with statistical approaches to remove error. The qm and Kb values confirm better adsorption capacity and binding strength for Pb2+ ions as compared to the values reported in the literature.

Adsorption mechanism of Pb 2+ ions by Fe 3 O 4 , SnO 2 , and TiO 2 nanoparticles

Magnetic nanoparticles of Fe3O4 (magnetite) have been synthesized from natural sand iron by co-precipitation method. The nanoparticles were synthesized using HCl as solvent and NH3 as co-precipitate. The nanoparticles synthesized at 70°C in two different treatments. Sample without Polyethylene Glycol (PEG) 6000 noted by A and sample with PEG 6000 noted by B symbol. The measurement that have been done for both samples were XRD (X-ray diffraction), FTIR (Fourier Transform Infrared) Spectrometry, SEM (Scanning electron microscopy), VSM (Vibrating sample magnetometer) and SAA (Surface area analyzer). The results showed that both samples were having Fe3O4 phases. Particle size, coercivity and magnetic saturation of B samples were smaller than A samples. But the surface area of B sample was larger than A sample. Both samples were then used to adsorb Cu and Pb ions using shaker method. Adsorption analysis from Atomic Adsorption Spectroscopy (AAS) showed that B was more effectivein adsorbing metal ions than A. The adsorption value of Cu and Pb ions were 79 and 91% respectively.

https://iopscience.iop.org/article/10.1088/1742-6596/776/1/012020/pdf

The synthesization of Fe3O4 magnetic nanoparticles based on natural iron sand by co-precipitation method for the used of the adsorption of Cu and Pb ions

/pdf/synthesis-of-nanoparticles-fe3o4-peg-ppy-based-on-natural-fc0qs44udt.pdf

SYNTHESIS OF NANOPARTICLES Fe3O4/PEG/PPy-BASED ON NATURAL IRON SAND

Transmission-path dependent electron hopping transport in thin films and nanorods of NiO

Two–dimensional (2D) 4H-polytype tin disulfide (SnS2) flakes are synthesized using the chemical vapor transport technique. The weak Van der Waals force between the 2D SnS2 layers offers an easy exfoliation of flakes down to a bilayer of thickness ≈2.02 (±0.1) nm using a mechanical exfoliation technique. The optical and field effect transistor (FET) characteristics of the exfoliated 2D 4H-SnS2 layers are studied. The exfoliated layers are used to fabricate the ≈13-layered SnS2 FET. The 4H-SnS2 exhibits a high on/off ratio of ≈106 and mobility ≈1–4 cm2 V−1 s−1. The low mobility of the 4H-SnS2 FET devices shows an insulating state concordant with the 2D Motts variable range hopping mechanism at varying temperatures. Moreover, it is found that the optical bandgap of the 2D SnS2 single-crystal layers is largely widened for the bilayers and tri-layers. The optical bandgap energies vary in the range of 2.56–1.99 eV. The significant alteration in bandgap energies of ≈0.57 eV offers downscaling of the 2D nanoscale semiconducting devices. Such layer-sensitive changes in optical transmittance, absorbance, and bandgap energies are reflected in Commission Internationale de L'Eclairage (CIE) chromaticity, showing the distinct color of transmittance through various 2D 4H-SnS2 layers. 

C. S. Saragih

Papers

The synthesization of Fe3O4 magnetic nanoparticles based on natural iron sand by co-precipitation method for the used of the adsorption of Cu and Pb ions

Superparamagnetic Behaviour and Surface Analysis of Fe3O4/PPY/CNT Nanocomposites

SYNTHESIS OF NANOPARTICLES Fe3O4/PEG/PPy-BASED ON NATURAL IRON SAND

Transmission-path dependent electron hopping transport in thin films and nanorods of NiO

Layer‐Dependent Optical Modulation and Field‐Effect‐Transistor in Two‐Dimensional 4H‐SnS2 Layers