Effect of Zn nonmagnetic element doping and a polyvinyl pyrrolidone shell layer on the superparamagnetism and stability properties of magnetic nanoparticles

Abstract

Zn x Fe1−x Fe2O4 nanoparticles (x = 0.0–0.25) were synthesized by the coprecipitation method. Their microstructure was investigated by X-ray diffraction with Rietveld refinement software, energy-dispersive X-ray spectroscopy, transmission electron microscopy, and Fourier transform infrared absorption spectroscopy. Their thermal, magnetic properties were investigated by thermogravimetric analysis and vibrating-sample magnetometer. The nanoparticles exhibited superparamagnetic properties, with a maximum saturation magnetization of 80.2 emu g−1 in H = 11 000 Oe at room temperature for sample with x = 0.20. The Zn nonmagnetic element content is related to the cation distribution in the superlattices and magnetic moment of the particles. The Zn0.15Fe0.85Fe2O4 nanoparticles were coated with polyvinyl pyrrolidone (PVP) with different PVP mass. Their core–shell structure was investigated, the results showed that their chemical stability and saturation magnetization were greater than those of pure Fe3O4. PVP has biological compatibility; thus, Fe0.85Zn0.15Fe2O4/PVP0.75 nanocomposite has the potential to be widely used in medical biology, science and technology.

Role of Zn And Polyaniline In Magnetic Nanocomposites And Enhanced Arsenic Adsorption Capacity In Wastewater

“…In Fig. 1, the diffraction peaks of ( 220), ( 311), ( 400), ( 442), ( 511), (440) of the Fe 0.90 Zn 0.10 Fe 2 O 4 (S 0 ) sample were completely tted with the standard diffraction pattern of Fe 3 O 4 as in our previous publication [31], and demonstrated the centered face cubic structure. Similarly, the XRD patterns of S 2 and S 3 samples showed the same diffraction peaks as that of Fe 3 O 4 sample, which proved that the Zn 2+ doping as well as the addition of polymer did not affect the crystal structure of materials.…”

“…The magnetic moment depends on the content of x that is considered due to the decision of spin direction of Fe x 3+ in B-site, but do not depends on the presence of non-magnetic Zn ions [19,31]. This has been clearly explained in our recent publication [31]. Therefore, the saturation magnetization of Fe 0.90 Zn 0.10 Fe 2 O 4 is higher than Fe 3 O 4 [30,31].…”

“…2.2. Synthesis of Fe 0.90 Zn 0.10 Fe 2 O 4 by chemical method A detailed synthesis procedure was described in our previous paper [30,31] solution. These mixed solutions were stirred until they turned to yellow in color.…”

“…The divalent metal ions like Mn 2+ , Cu 2+ and Zn 2+ are usually substituted into B-site to form inverse spinel ferrites such as Fe 1−x Mn x Fe 2 O 4 (with x = 0 ÷ 0.15 or 0.5) [27,30], Fe 1−x Cu x Fe 2 O 4 (with x = 0 ÷ 0.15) [30], Ni x Fe 3-x O 4 sample system (x = 0.04; 0.06; 0.11) [25], or Ni 1−x Zn x Fe 2 O 4 sample system (x = 0, 0.5 and 1) [26]. However, Fe 1−x Zn x Fe 2 O 4 (x = 0; 0.2; 0.4; 0.5) thin lms or nanopowders with pretty large magnetization were con rmed by the partial substitutions of Zn 2+ ions into A-sites [19,31].…”

“…Polyaniline (PANI) is well-known as a conductive polymer whose high electrical conductivity has been discovered and is expected to play an increasingly signi cant role in many elds due to its easy synthesis, physicochemical stability, and simple doping chemistry. In recent, the substitution of Mn, Cu, Zn elements for Fe ions and the coating of magnetic nanoparticles by poly(1-naphthylamine), polyvinyl pyrrolidone have been studied [30,31,36] in order to stabilize the physicochemical properties and enhance their applicability. In this work, we discuss the synthesis, magnetic properties, microstructure of PANI/Fe 0.90 Zn 10 Fe 2 O 4 nanocomposites with different mass ratios of PANI/Fe 0.90 Zn 0.10 Fe 2 O 4 and the Zn 2+ substitution for Fe 2+ .…”