scholarly journals Synthesis and Characterization of Magnetite-Alginate Nanoparticles for Enhancement of Nickel and Cobalt Ion Adsorption from Wastewater

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Omnia A. A. El-Shamy ◽  
Ragaa E. El-Azabawy ◽  
Olfat. E. El-Azabawy

Superparamagnetic magnetite-alginate nanoparticles (M-AlgNPs) were synthesized utilizing a coprecipitation method. Then, the prepared M-AlgNPs were characterized via Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction spectroscopy (XRD) to affirm the formation and the crystallinity of this composite. In addition, the surface morphology of the prepared nanoparticles was inspected by transmission electron microscopy (TEM) which revealed well-dispersed nanoparticles of Fe3O4 into alginate. The adsorption characteristics of the synthesized nanoparticles for removing Ni+2 and Co+2 from wastewater were evaluated via atomic absorption measurements (AAS). The elimination efficiency of the M-AlgNPs was detected at pH=7 in 100 ppm (initial concentration) of Ni+2 and Co+2, separately. The M-AlgNPs provided the maximum equilibrium uptake percentage for Ni+2 and Co+2 of 97.88 and 95.01%, respectively. The adsorption of Ni+2 and Co+2 onto the M-AlgNP surface was found to fit the Langmuir model with R2 values higher than that obtained from the Freundlich model for both metal ions. Moreover, RL “separating factor” for the adsorption process was assessed and found to be less than unity; this expresses the higher ability of the investigated metal ions to be adsorbed onto the M-AlgNP surface. The adsorption method was discovered to be pH-dependent and well-suited to the isothermal equations of Langmuir and Freundlich. For regeneration studies, M-AlgNPs have been investigated and results confirmed that it could be reused with effective sorption capacity over three cycles.

Author(s):  
R. E. Herfert

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.


1995 ◽  
Vol 418 ◽  
Author(s):  
J. Forbes ◽  
J. Davis ◽  
C. Wong

AbstractThe detonation of explosives typically creates 100's of kbar pressures and 1000's K temperatures. These pressures and temperatures last for only a fraction of a microsecond as the products expand. Nucleation and growth of crystalline materials can occur under these conditions. Recovery of these materials is difficult but can occur in some circumstances. This paper describes the detonation synthesis facility, recovery of nano-size diamond, and plans to synthesize other nano-size materials by modifying the chemical composition of explosive compounds. The characterization of nano-size diamonds by transmission electron microscopy and electron diffraction, X-ray diffraction and Raman spectroscopy will also be reported.


2012 ◽  
Vol 600 ◽  
pp. 174-177 ◽  
Author(s):  
Jian Fei Xia ◽  
Zong Hua Wang ◽  
Yan Zhi Xia ◽  
Fei Fei Zhang ◽  
Fu Qiang Zhu ◽  
...  

Zirconia-graphene composite (ZrO2-G) has been successfully synthesized via decomposition of ZrOCl2•6H2O in a water-isopropanol system with dispersed graphene oxide (GO) utilizing Na2S as a precursor could enable the occurrence of the deposition of Zr4+ and the deoxygenation of GO at the same time. Transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) techniques were used to characterize the samples. It was found that graphene were fully coated with ZrO2, and the ZrO2 existing in tetragonal phase, which resulted in the formation of two-dimensional composite.


2012 ◽  
Vol 174-177 ◽  
pp. 508-511
Author(s):  
Lin Lin Yang ◽  
Yong Gang Wang ◽  
Yu Jiang Wang ◽  
Xiao Feng Wang

BiFeO3 polyhedrons had been successfully synthesized via a hydrothermal method. The as-prepared products were characterized by power X-ray diffraction (XRD) pattern, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The possible mechanisms for the formation of BiFeO3 polyhedrons were discussed. Though comparison experiments, it was found that the kind of precursor played a key role on the morphology control of BiFeO3 crystals.


2017 ◽  
Vol 8 ◽  
pp. 1257-1265 ◽  
Author(s):  
Urszula Klekotka ◽  
Magdalena Rogowska ◽  
Dariusz Satuła ◽  
Beata Kalska-Szostko

Ferrite nanoparticles with nominal composition Me0.5Fe2.5O4 (Me = Co, Fe, Ni or Mn) have been successfully prepared by the wet chemical method. The obtained particles have a mean diameter of 11–16 ± 2 nm and were modified to improve their magnetic properties and chemical activity. The surface of the pristine nanoparticles was functionalized afterwards with –COOH and –NH2 groups to obtain a bioactive layer. To achieve our goal, two different modification approaches were realized. In the first one, glutaraldehyde was attached to the nanoparticles as a linker. In the second one, direct bonding of such nanoparticles with a bioparticle was studied. In subsequent steps, the nanoparticles were immobilized with enzymes such as albumin, glucose oxidase, lipase and trypsin as a test bioparticles. The characterization of the nanoparticles was acheived by transmission electron microscopy, X-ray diffraction, energy dispersive X-ray and Mössbauer spectroscopy. The effect of the obtained biocomposites was monitored by Fourier transform infrared spectroscopy. The obtained results show that in some cases the use of glutaraldehyde was crucial (albumin).


Author(s):  
Xianxue Li

Abstract Well-dispersed cerium-doped Y2SiO5 (Ce:YSO) phosphor particles with spherical morphology and good luminescence intensity have been achieved by a solvothermal method with ethanol and water as solvent media. X-ray diffraction, Fourier transform infrared spectroscopy, fluorescence spectrophotometry and transmission electron microscopy were employed to characterize the as-synthesized Ce:YSO precursor and powders. The results showed that pure-phase Ce:YSO powders with a mean particle size of about 162 nm were accurately available at 310°C and above. The fluorescence ability and persistent luminescence decay properties of the Ce:YSO powders were also studied, and the excellent fluorescence properties could be attributed to the homogeneous Ce:YSO particles obtained through the solvothermal method.


2005 ◽  
Vol 3 (3) ◽  
pp. 358-360 ◽  
Author(s):  
Jia Rong-Li ◽  
Wang Cheng-Yang ◽  
Zhu Bin

Superfine mesocarbon microbead powders (SFMCMBs) as the new supports for platinum electrocatalysts were first investigated. The Pt∕SFMCMB electrocatalysts were prepared by an impregnation-reduction method, with hexachloroplatinic acid as the platinum precursor and formaldehyde as the reducing agent. The catalysts were characterized with x-ray diffraction (XRD), field emission gun transmission electron microscope (TEM), and electrochemical analysis. TEM photos showed the platinum particles were dispersed uniformly on the surface of SFMCMBs and there existed a little aggregation of platinum particles in the Pt∕SFMCMB catalysts. The TEM photos showed the existence of the platinum on the supports where the average platinum particle size were 4-6nm. The electrochemical analysis proved that SFMCMBs are excellent candidates to be used as the support of platinum electrocatalyst for methanol electrochemical oxidation as the potential catalyst candidate for direct methanol fuel cells (DMFCs).


1996 ◽  
Vol 449 ◽  
Author(s):  
P. Kung ◽  
A. Saxler ◽  
D. Walker ◽  
X. Zhang ◽  
R. Lavado ◽  
...  

ABSTRACTWe present the metalorganic chemical vapor deposition growth, n-type and p-type doping and characterization of AlxGa1-xN alloys on sapphire substrates. We report the fabrication of Bragg reflectors and the demonstration of two dimensional electron gas structures using AlxGa1-xN high quality films. We report the structural characterization of the AlxGa1-xN / GaN multilayer structures and superlattices through X-ray diffraction and transmission electron microscopy. A density of screw and mixed threading dislocations as low as 107 cm-2 was estimated in AlxGa1-xN / GaN structures. The realization of AlxGa1-xN based UV photodetectors with tailored cut-off wavelengths from 365 to 200 nm are presented.


2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Beata Zielińska ◽  
Ewa Mijowska ◽  
Ryszard J. Kalenczuk

K-Ta mixed oxides photocatalysts have been prepared by impregnation followed by calcination. The influence of the reaction temperature (450°C–900°C) on the phase formation, crystal morphology, and photocatalytic activity in hydrogen generation of the produced materials was investigated. The detailed analysis has revealed that all products exhibit high crystallinity and irregular structure. Moreover, two different crystal structures of potassium tantalates such as KTaO3and K2Ta4O11were obtained. It was also found that the sample composed of KTaO3and traces of unreacted Ta2O5(annealed at 600°C) exhibits the highest activity in the reaction of photocatalytic hydrogen generation. The crystallographic phases, optical and vibronic properties were examined by X-ray diffraction (XRD) and diffuse reflectance (DR) UV-vis and resonance Raman spectroscopic methods, respectively. Morphology and chemical composition of the produced samples were studied using a high-resolution transmission electron microscope (HR-TEM) and an energy dispersive X-ray spectrometer (EDX) as its mode.


2013 ◽  
Vol 873 ◽  
pp. 152-157
Author(s):  
Long Long Chen ◽  
Jun Ming Li ◽  
Xiao Min Gong ◽  
Jian Li

Using a chemically induced transition in an FeCl2 solution, γ-Fe2O3 nanoparticles can be prepared from an amorphous precursor composed of FeOOH and Mg (OH)2. Surface modification by adding ZnCl2 during liquid-phase synthesis was attempted. The magnetization, morphology, crystal structure, and chemical species of as-prepared samples were characterized by vibrating sample magnetometer (VSM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray energy-dispersive spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). The experimental results showed that the surface of the γ-Fe2O3 nanoparticles can be modified by adding ZnCl2 to form composite nanoparticles with a γ-Fe2O3/ZnFe2O4 ferrite core coated with Zn (OH)2 and absorbed FeCl36H2O; this modification can be enhanced by additional NaOH.


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