Wyniki wyszukiwania - BazTech

1

Synthesis of Silica Microspheres Containing Iron Oxide Nanoparticles for Removal of Organic Pollutant by Adsorption and Photocatalytic Decomposition

Cho Young-Sang, Sung Sohyeon

Archives of Metallurgy and Materials

|

2021

|

Vol. 66, iss. 3

771--776

EN

Iron oxide nanoparticles were incorporated to form composite microspheres of SiO2 and Fe2O3 for magnetic separation of the particles after adsorption or photochemical decomposition. Economic material, sodium silicate, was purified by ion exchange to prepare aqueous silicic acid solution, followed by mixing with iron oxide nanoparticles. Resulting aqueous dispersion was emulsified, and composite microspheres of SiO2 and Fe2O3 was formed from the emulsion droplets as micro-reactors during heating. Removal of methylene blue using the composite microspheres was performed by batch adsorption process. Synthesis of composite microspheres of silica containing Fe2O3 and TiO2 nanoparticles was also possible, the particles could be separated using magnets efficiently after removal of organic dye.

2

Heisenberg Analytical-Numerical Model of Nanoparticle with Para- and Ferromagnetism

Leble Sergey, Chychkalo Anastasiia

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

|

2019

|

Vol. 23, No 3

303--317

EN

Two models of two- and three-layers of a magnetic nanoparticle are presented applying the Heisenberg theory with the parameter (exchange integral and closest neighbors) values for surface layers, which differ from the bulk layer values. The difference in the numbers of closest neighbors is taken into account. The corresponding distribution and partition functions are constructed. The magnetization of the particles is calculated by the conventional transition to thermodynamics. The results are illustrated by plots, representing magnetization curves and hysteresis loops for the layer contributions. The magnetization curves for both models are compared.

3

The Design of RNA Biosensor Based on Nano-gold and Magnetic Nano-particle

Yang Jing, Yin Zhi-xiang, Cui Jian-zhong, Huang Kai-feng

Fundamenta Informaticae

|

2019

|

Vol. 164, nr 2-3

289--298

EN

Detecting the quality of drinking water is very important in researching the current status and predicting trends of variation, as well as fundamentally solving the water pollution problem. Recently, the application and development of biosensor provide a powerful analytical tool for detecting pollutants of drinking water, but high selectivity, specificity, short response time, and low cost are particularly desired in the detection process. In this paper, RNA molecules in combination with nano-gold and magnetic nano-particles were proposed as design strategies of the biosensor. The proposed designs have distinct advantages over conventional biosensor in the following aspects: the high affinity capacity, sensitivity, and practicability. Our work provided an alternative method to monitor the environment of drinking water, and may find applications in various monitoring fields.

4

Synthesis, investigation on structural and electrical properties of cobalt doped Mn–Zn ferrite nanocrystalline powders

Bhuvaneswari M., Sendhilnathan S., Kumar M., Tamilarasan R., Giridharan N. V.

Materials Science Poland

|

2016

|

Vol. 34, No. 2

344--353

EN

Synthesis of CoxMnyZnyFe2O4 (x = 0.1, 0.5, 0.9 and y = 0.45, 0.25, 0.05) nanocrystalline powders was done by chemical co-precipitation method. The crystal structure was determined by using X-ray diffraction (XRD) studies. The crystallite size and lattice parameters were calculated from the XRD data. The XRD results revealed that the crystallite size of the nanocrystalline powder was found to decrease from 37 nm to 28 nm with the substitution of cobalt. The effect of cobalt ions on the crystallization process, the lattice parameters and electrical properties of Mn–Zn ferrites has been also investigated. The AC conductivity increased with an increase in frequency but it decreased with an increase in cobalt content. The complex impedance analysis of the data showed that the resistive and capacitive properties of the Co–Mn–Zn ferrite are predominant due to the fact that the processes are associated with the grains and grain boundaries. The dielectric constant and dielectric loss dependence on doping level and frequency at room temperature were also studied.

5

Dobór parametrów prowadzenia reakcji otrzymywania nanocząstek magnetycznych otoczkowanych nanozłotem

Tyliszczak B., Bialik-Wąs K., Drabczyk A., Kudłacik S.

Infrastruktura i Ekologia Terenów Wiejskich

|

2016

|

nr III/2

857--866

PL

W artykule opisano dobór parametrów prowadzenia reakcji otrzymywania nanocząstek magnetycznych (nanoFe3O4) na drodze syntezy Massarta. Jednakże nanocząstki magnetyczne należą do bardzo niestabilnych układów i szybko ulegają aglomeracji. Dlatego też, w drugim etapie syntezy przeprowadzono otoczkowanie nanocząstek magnetycznych nanozłotem (nanoFe3O4/Au) w obecności odpowiedniego stabilizatora. W związku z tym przeprowadzono syntezy w obecności 10% (wag.) r-ru PVP, 0,1M r-rze cytrynianu sodu oraz 3% r-ru gumy arabskiej, w temperaturze pokojowej oraz podwyższonej do 80°C. Przebieg reakcji kontrolowano za pomocą spektrofotometrii UV-Vis. Uzyskane nanocząstki magnetyczne otoczkowane nanozłotem zostały poddane analizie rentgenograficznej oraz dla wybranych próbek wyznaczono średni rozmiar cząstek za pomocą metody dynamicznego rozpraszania światła laserowego (DLS).

EN

The article describes the selection of reaction parameters for preparing magnetic nanoparticles (nanoFe3O4 ) by Massart’s synthesis. However, the magnetic nanoparticles belong to a group of unstable systems and rapidly agglomerate. Therefore, in the second step of the synthesis encapsulation of magnetic nanoparticles usung gold nanoparticles (nanoFe3 O4 /Au) in the presence of a suitable stabilizer was conducted. Hence, the synthesis was carried out in the presence of 10% (wt.) solution of PVP, 0.1 M sodium citrate and 3% solution of gum arabic. Such synthesis were conducted at room temperature and at 80°C. Progress of the reaction was monitored using UV-Vis spectrophotometry. The resulting magnetic-nanogold encapsulated nanoparticles were analyzed using X-ray diffraction. What is more, for selected samples the average particle size was determined using dynamic light scattering (DLS).

6

FMR study of gamma-Fe2O3 magnetic nanoparticles in a multiblock poly(ether-ester) copolymer matrix

Guskos N., Typek J., Maryniak M., Roslaniec Z., Petridis D., Kwiatkowska M.

Materials Science Poland

|

2005

|

Vol. 23, No. 4

971--976

EN

Four samples containing gamma-Fe2O3 magnetic nanoparticles dispersed at a concentration of 0.1 % (samples I and I') and 0.3 % (samples II and II') in a polymer matrix have been prepared. The polymer filler was in two forms: as solid-state grains (samples I and II) and as a liquid solution in trichloromethane (samples I' and II'). The typical size of the magnetic nanoparticles was 10 nm. The samples were characterized by XRD and TEM spectroscopy. Ferromagnetic resonance (FMR) measurements were carried out at room (RT) and liquid nitrogen (LNT) temperatures for all four samples. An intense resonance absorption line from gamma-Fe2O3 was recorded, with a slightly asymmetric line shape. The FMR spectra at RT and LNT are almost the same, as could be expected for the composite matrix. For samples II and II', the resonance lines are centred at Hr = 3039(10) Gs and Hr = 3197 (10) Gs, respectively, with linewidths of deltaH = 1289(5) Gs and deltaH = 1364(5) Gs, respectively. For samples I and I', the following values of resonance line parameters were obtained: Hr = 3172(10) Gs for sample I', and Hr = 2958(10) Gs for sample I, with linewidths of deltaH = 1279(5) Gs and deltaH = 1200(5) Gs, respectively. In both cases the resonance field for samples obtained from a solid state filler is shifted to lower magnetic fields as compared to samples made from a suspension filler, which suggests stronger ferromagnetic interactions in these materials.