scholarly journals One-step approach for the synthesis of CoFe2O4@rGO core-shell nanocomposites as efficient adsorbent for removal of organic pollutants

2016 ◽  
Vol 75 (2) ◽  
pp. 397-405 ◽  
Author(s):  
Z. J. Song ◽  
W. Ran ◽  
F. Y. Wei
Keyword(s):  
Graphene Oxide ◽  
Adsorption Capacity ◽  
Average Diameter ◽  
Core Shell ◽  
X Ray Diffraction ◽  
Anionic Dyes ◽  
Reduced Graphene ◽  
Key Factor ◽  
One Step ◽  
20 Nm

CoFe2O4-reduced graphene oxide nanocomposites (CFG) have been successfully synthesized via one-step solvothermal method. The prepared CFG are characterized by X-ray diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy, field emission scanning electron microscopy (FESEM), vibrating sample magnetometer and so on. The FESEM results show that CFG have uniform core-shell structure with an average diameter of about 75 nm and the thickness of the outer graphene shell is about 15–20 nm. The mass ratio of CoFe2O4 to graphene oxide is a key factor affecting the formation of core-shell hybrids. CFG display much higher adsorption capacity for anionic dyes than cationic dyes owing to the favorable electrostatic interaction. The adsorption capacity for methyl orange is observed as high as 263 mg g–1 at 298 K, and the adsorption isotherms follow the Langmuir model. Furthermore, the specific saturation magnetization (Ms) of CFG is 32.8 emu g–1, and the as-synthesized nanocomposites can be easily separated by external magnetic field after adsorption. The results suggest that CFG have great potential for the practical industrial wastewater treatment.

A three-dimensional nickel-doped reduced graphene oxide composite for selective separation of hemoglobin with a high adsorption capacity

RSC Advances ◽  
2016 ◽  
Vol 6 (61) ◽  
pp. 56278-56286 ◽  
Author(s):  
Lei Chen ◽  
Zhang-Run Xu
Keyword(s):  
Graphene Oxide ◽  
Adsorption Capacity ◽  
Reduced Graphene Oxide ◽  
Self Assembly ◽  
Three Dimensional ◽  
High Adsorption ◽  
Reduced Graphene ◽  
One Step ◽  
Reduced Graphene Oxide Aerogel ◽  
High Adsorption Capacity

A 3D nickel-doped reduced graphene oxide aerogel was prepared by one-step reduction and self-assembly, which exhibited favorable selectivity and high adsorption capacity for isolating hemoglobin.

One-step preparation and characterization of core-shell SiO2/Ag composite spheres by pulse plating

2017 ◽  
Vol 24 (3) ◽  
pp. 423-427 ◽  
Author(s):  
Li Xiong ◽  
Xiangping Huang ◽  
Ya Liu ◽  
Liqing Pan
Keyword(s):  
Structural Characteristics ◽  
Pulse Plating ◽  
Core Shell ◽  
X Ray Diffraction ◽  
Simple Method ◽  
Transmission Electron ◽  
Surface Enhanced Raman ◽  
One Step ◽  
Enhanced Raman Scattering ◽  
20 Nm

AbstractA simple method of one-step pulse plating was used in the fabrication of core-shell SiO2/Ag composite spheres. Structural characteristics and morphologies of the prepared SiO2/Ag composite spheres are characterized by means of X-ray diffraction, scanning electron microscope, and transmission electron microscopy. The Ag shell is uniformly coated on the surface of SiO2 spheres with the thickness of about 20 nm. Photoluminescence (PL) spectrum has revealed that PL of the core-shell samples is much stronger than that of bare SiO2 spheres. Raman spectrometer measurements show that the SiO2/Ag composite spheres have excellent surface-enhanced Raman scattering performance. In addition, the current-voltage characteristic of SiO2/Ag composite spheres has improved at the same time.

scholarly journals ADSORPTION OF URANIUM FROM AQUEOUS SOLUTION BY Cu0.5Ni0.5Fe2O4 – REDUCED GRAPHENE OXIDE NANOCOMPOSITES

2018 ◽  
Vol 54 (5A) ◽  
pp. 9
Author(s):  
Tran Quang Dat
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Ph Effect ◽  
Maximum Adsorption Capacity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Reduced Graphene ◽  
20 Nm ◽  
Oxide Composites ◽  
Efficient Adsorbent

Cu0.5Ni0.5Fe2O4 – reduced graphene oxide composites (CNF-rGO) as an efficient adsorbent for the adsorption of uranium (VI) have been synthesized by a two-steps methods. The structures and the physicochemical properties of adsorbents are characterized by Scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy (RAMAN) and Vibrating sample magnetometer (VSM) measurement. It was found that rGO were exfoliated and decorated homogeneously with CNF nanoparticles having diameters of 20 nm. The saturated magnetization (Ms) value was estimated to be 60 emu/g, remanences (Mr) and coercive forces (Hc) near to zero, indicating that obtained material is superparamagnetic. The pH effect, contact time and adsorption isotherms were examined in batch experiments. The adsorption isotherm agreed well with the Langmuir model, having a maximum adsorption capacity of 256 mg/g, at pH = 6, T = 298 K.

Controlled Growth of ZnO Nanocrystals on the Surface of SiO2 Spheres

2009 ◽  
Vol 151 ◽  
pp. 264-268 ◽  
Author(s):  
Yuliya V. Yermolayeva ◽  
Yuriy N. Savin ◽  
Alexander V. Tolmachev
Keyword(s):  
Average Diameter ◽  
Core Shell ◽  
X Ray Diffraction ◽  
X Ray ◽  
Zno Nanocrystals ◽  
Transmission Electron ◽  
Zno Particles ◽  
One Step ◽  
Shell Particles ◽  
Sio2 Spheres

The “islands” of ZnO nanocrystals on amorphous monodisperse 200 nm SiO2 spheres (core-shell particles) were obtained by simple one-step technique based on low-temperature crystallization from liquid phase. The influence of starting reagents types and concentration of zinc ions in the reaction mixture on the morphology of ZnO shells obtained was studied. Crystalline structure of ZnO nanocrystals obtained was proofed by the X-ray diffraction data. The average diameter of ZnO nanocrystals on SiO2 spheres is 10 nm according to X-ray diffraction (XRD) and transmission electron microscopy (TEM) data. It was shown that SiO2/ZnO particles obtained have high luminescence characteristics. Photoluminescence spectra of core-shell SiO2/ZnO particles show two emission peaks centred at 386 nm and 570 nm. Core-shell SiO2/ZnO particles obtained are perspective for active photonic crystals creation for UV-spectral region.

scholarly journals Applicability of Goethite/Reduced Graphene Oxide Nanocomposites to Remove Lead from Wastewater

Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1580
Author(s):  
Franklin Gordon-Nuñez ◽  
Katherine Vaca-Escobar ◽  
Milton Villacís-García ◽  
Lenys Fernández ◽  
Alexis Debut ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Adsorption Capacity ◽  
Reduced Graphene Oxide ◽  
Lead Ion ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Reduced Graphene ◽  
Scanning Transmission ◽  
Efficient Alternative

Lead ion in drinking water is one of the most dangerous metals. It affects several systems, such as the nervous, gastrointestinal, reproductive, renal, and cardiovascular systems. Adsorption process is used as a technology that can solve this problem through suitable composites. The adsorption of lead (Pb(II)) on graphene oxide (GO) and on two goethite (α-FeOOH)/reduced graphene oxide (rGO) composites (composite 1: 0.10 g GO: 22.22 g α-FeOOH and composite 2: 0.10 g GO: 5.56 g α-FeOOH), in aqueous medium, was studied. The GO was synthesized from a commercial pencil lead. Composites 1 and 2 were prepared from GO and ferrous sulfate. The GO and both composites were characterized by using scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), Raman spectroscopy, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and dynamic light scattering (DLS). The adsorption capacity of Pb(II) on the GO and both composites was evaluated through adsorption isotherms. Composite 1 presented a significant agglomeration of α-FeOOH nanorods on the reduced graphene oxide layers. Meanwhile, composite 2 exhibited a more uniform distribution of nanorods. The adsorption of Pb(II) on the three adsorbents fits the Langmuir isotherm, with an adsorption capacity of 277.78 mg/g for composite 2200 mg/g for GO and 138.89 mg/g for composite 1. Composite 2 emerged as a highly efficient alternative to purify water contaminated with Pb(II).

Hydrothermal Synthesis of N-Doped Graphene for Supercapacitor Electrodes

2020 ◽  
Vol 20 (5) ◽  
pp. 3258-3264 ◽  
Author(s):  
Elena N. Gorenskaia ◽  
Bato Ch. Kholkhoev ◽  
Viktor G. Makotchenko ◽  
Mariia N. Ivanova ◽  
Vladimir E. Fedorov ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Hydrothermal Process ◽  
High Specific Capacitance ◽  
Redox Activity ◽  
Scanning Electron Micrographs ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Reduced Graphene ◽  
Doped Graphene ◽  
One Step

N-doped graphene based on graphene oxide and 3,3′,4,4′-tetraaminodiphenyl oxide (TADPO) was obtained using a one-step hydrothermal process. The resulting materials were fully characterized using elemental analysis, infrared spectroscopy, Raman spectroscopy, thermogravimetric analysis, X-ray diffraction, scanning electron micrographs, and transmission electron microscopy. The findings reveal that benzimidazole rings were formed during the reaction, and the mass content of nitrogen in the obtained material varied from 12.3% to 14.7%, depending on the initial concentration of TADPO. Owing to the redox activity of benzimidazole rings, the new N-doped graphene materials demonstrated a high specific capacitance, reaching 340 F g−1 at 0.1 A g−1, which was significantly higher than that of the sample of reduced graphene oxide obtained under similar conditions without the use of TADPO (169 F g−1 at 0.1 A g−1). The resulting material also exhibited good cyclic stability after 5000 cycles.

One-step combustion synthesis of NiFe2O4-reduced graphene oxide hybrid materials for photodegradation of methylene blue

2014 ◽  
Vol 07 (01) ◽  
pp. 1350065 ◽  
Author(s):  
Dafeng Zhang ◽  
Qi Ding ◽  
Xipeng Pu ◽  
Changhua Su ◽  
Xin Shao ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Hybrid Materials ◽  
Combustion Method ◽  
High Specific Surface Area ◽  
X Ray Diffraction ◽  
Adsorptive Property ◽  
Transmission Electron ◽  
Reduced Graphene ◽  
One Step

NiFe 2 O 4-reduced graphene oxide (RGO) hybrid materials (NFRGs) were synthesized by a simple one-step combustion method. The structures, morphologies and magnetic properties were characterized by X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, and vibrating sample magnetometer analysis. The results show that graphene oxide sheets are not oxidized, but reduced to RGO. The superparamagnetic behavior of NFRGs was observed. The as-synthesized magnetically separable NFRGs show improved photodegradation performance when compared to neat NiFe 2 O 4, attributed to the narrowing band gap, the efficient transfer of photo-generated electron from NiFe 2 O 4 to RGO sheets, and the improved adsorptive property of photocatalyst due to the high specific surface area of RGO sheets.

scholarly journals One-step synthesis of nitrogen-grafted copper-gallic acid for enhanced methylene blue removal

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shella Permatasari Santoso ◽  
Vania Bundjaja ◽  
Artik Elisa Angkawijaya ◽  
Chintya Gunarto ◽  
Alchris Woo Go ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Adsorption Capacity ◽  
Gallic Acid ◽  
Synthesis Method ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
One Step ◽  
Detailed Assessment ◽  
Higher Temperature

AbstractNitrogen-grafting through the addition of glycine (Gly) was performed on a metal- phenolic network (MPN) of copper (Cu2+) and gallic acid (GA) to increase its adsorption capacity. Herein, we reported a one-step synthesis method of MPN, which was developed according to the metal–ligand complexation principle. The nitrogen grafted CuGA (Ng-CuGA) MPN was obtained by reacting Cu2+, GA, and Gly in an aqueous solution at a molar ratio of 1:1:1 and a pH of 8. Several physicochemical measurements, such as Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), N2 sorption, X-ray diffraction (XRD), and thermal gravimetry analysis (TGA), were done on Ng-CuGA to elucidate its characteristics. The analysis revealed that the Ng-CuGA has non-uniform spherical shaped morphology with a pore volume of 0.56 cc/g, a pore size of 23.25 nm, and thermal stability up to 205 °C. The applicational potential of the Ng-CuGA was determined based on its adsorption capacity against methylene blue (MB). The Ng-CuGA was able to adsorb 190.81 mg MB per g adsorbent at a pH of 6 and temperature of 30 °C, which is 1.53 times higher than the non-grafted CuGA. Detailed assessment of Ng-CuGA adsorption properties revealed their pH- and temperature-dependent nature. The adsorption capacity and affinity were found to decrease at a higher temperature, demonstrating the exothermic adsorption behavior.

scholarly journals Magnetization of Ultraviolet-Reduced Graphene Oxide Flakes in Composites Based on Polystyrene

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2519
Author(s):  
Alexander N. Ionov ◽  
Mikhail P. Volkov ◽  
Marianna N. Nikolaeva ◽  
Ruslan Y. Smyslov ◽  
Alexander N. Bugrov
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Reduction Process ◽  
X Ray Diffraction ◽  
Mesoscopic Structure ◽  
Reduced Graphene ◽  
Study Results ◽  
Edge Defects ◽  
Mesoscopic Level ◽  
Ferromagnetic Hysteresis

This work presents our study results of the magnetization of multilayer UV-reduced graphene oxide (UV-rGO), polymer matrix (polystyrene), and a conjugated composite based on them. The mesoscopic structure of the composites synthesized in this work was studied by such methods as X-ray diffraction, SEM, as well as NMR-, IR- and Raman spectroscopy. The magnetization of the composites under investigation and their components was measured using a vibrating-sample magnetometer. It has been shown that the UV-reduction process leads to the formation of many submicron holes distributed inside rGO flakes, which can create edge defects, causing possibly magnetic order in the graphite samples under investigation on the mesoscopic level. This article provides an alternative explanation for the ferromagnetic hysteresis loop in UV-rGO on the base of superconductivity type-II.

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