Adsorption Mechanism and Electrochemical Performance of Congo Red onto Magnetic CuFe2O4 Nanoparticles

2020 ◽  
Vol 12 (5) ◽  
pp. 643-651
Author(s):  
Ao-Lin He ◽  
Yu-Wei Huang ◽  
Lei Fang ◽  
Jing Xu

Magnetic CuFe2O4 nanoparticles were synthesized by the facile alcohol-solution combustion approach, and they were characterized by transmission electron microscopy (TEM), energy dispersive X-ray Spectroscopy (EDX), scanning electron microscopy (SEM), X-ray diffraction (XRD) and vibrating sample magnetometer (VSM). The magnetic CuFe2O4 nanoparticles were employed to adsorb Congo red (CR) from aqueous medium. The study of magnetic CuFe2O4 nanoparticles for CR adsorption at room temperature was performed, and the Langmuir isotherm and pseudo-second kinetics model matched well with the adsorption process, those suggested that the mechanism of CuFe2O4 nanoparticles for CR adsorption followed the adsorption behavior of monolayer. The adsorbance descended with the increase of pH value, especially the pH value exceeded 7, and the adsorbance amounted to 77% of the initial one via 10 recycles. While, the electrochemical performances of bare magnetic glassy carbon electrode (MGCE), MGCE/CuFe2O4 nanoparticles, and MGCE/nanoparticles adsorbed CR were measured by EIS and CV.

2020 ◽  
Vol 12 (6) ◽  
pp. 744-749
Author(s):  
Dawei He ◽  
Shasha Li

Magnetic MnFe2O4 nanorods were fabricated by the alcohol-solution combustion–calcination technique. The morphology, microstructure, and composition of as-prepared MnFe2O4 nanorods were characterized using the transmission electron microscopy (TEM), the X-ray diffraction (XRD), the energy dispersive spectroscopy (EDS), and the vibrating sample magnetometer (VSM). Moreover, the magnetic MnFe2O4 nanorods were employed to remove reactive red 2BF (RR-2BF), the experimental results showed the pseudo-second-order kinetics model could be applied to describe the adsorption process of RR-2BF onto MnFe2O4 nanorods in the initial RR-2BF concentrations of 100–400 mg/L, while, the isotherm data of RR-2BF onto MnFe2O4 nanorods could conform to Langmuir model owing to the value of the square deviations, which revealed that, the adsorption of RR-2BF onto MnFe2O4 nanorods was the monolayer adsorption mechanism.


2012 ◽  
Vol 724 ◽  
pp. 205-208
Author(s):  
Li Yan Zhang ◽  
Fen Wang ◽  
Jian Feng Zhu

ZnO nanorods were prepared by heat treating of aqueous zinc acetate treated with organic of PVA. The products were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM). The results indicate that the as synthesized ZnO are hexagonal wurtzite nanorods with the maximum aspect ratio of 10:1 (100 nm in diameter and about 1 μm in length). The morphology of nanorods was formed by the regulation of appropriate organic under a pH value of 8.5. The growth mechanism of ZnO is proposed that the nanocrystals grow along a preferred direction in a growth tunnel provided by organics.


2021 ◽  
Author(s):  
Rong Chen ◽  
Dan Zhao ◽  
Yanmao Dong ◽  
Chengrun Cai ◽  
Yan Yuan ◽  
...  

Abstract manganese doped iron oxychloride (Mn-FeOCl) was synthesized by partial pyrolysis method. The Mn-FeOCl was used as heterogeneous catalyst to activate permonosulfate (PMS) for the degradation of azo dye acid red B(ARB) for the first time. The Mn-FeOCl was characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction spectroscopy (XRD). The effects of Mn-FeOCl dosage, PMS concentration, initial pH value, Cl ion concentration and humic acid (HA) dosage on the degradation of ARB by Mn-FeOCl/PMS were investigated. Results showed that the ARB was degraded effectively by Mn-FeOCl/PMS. The mineralization rate of ARB reached 42.5%. As the Mn-FeOCl dosage was 0.1g/L, PMS concentration was 1mmol/L, and ARB concentration was 0.05mmol/L, the degradation rate of ARB reached 99.4% in 30 minutes. With the increase of PMS dosage, Mn-FeOCl dosage, Cl− ion concentration and initial pH value, the decolorization effect of ARB increased. The reaction mechanism was analyzed by free radical quenching experiment and XPS. The main active species were determined as ·OH and SO4·− which generated by PMS activation. The SO4·−−was the main active species.


2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Yun Zhao ◽  
Fenfei Xiao ◽  
Qingze Jiao

Ni/Al layered double hydroxide (LDH) nanorods were successfully synthesized by the hydrothermal reaction. The crystal structure of the products was characterized by X-ray diffraction (XRD). The morphology of the products was observed using transmission electron microscopy (TEM) and field emission scanning electron microscopy (SEM). The influences of reaction time and pH value on the morphology of the Ni/Al LDHs were investigated. The result showed that the well-crystallized nanorods of Ni/Al LDHs could be obtained when the pH value was about 10.0 with a long reaction time (12–18 h) at 180°C.


2010 ◽  
Vol 24 (29) ◽  
pp. 5663-5673 ◽  
Author(s):  
J. P. BORAH ◽  
J. BARMAN ◽  
K. C. SARMA

Polyvinyl alcohol (PVA) has been used as a matrix to synthesize ZnS / PVA nanocomposite film on glass substrate by chemical method. Transmission electron microscopy (TEM), X-ray diffraction (XRD), Scanning electron microscopy (SEM) has been used for structural, morphological and compositional characterization. Optical properties have been studied by UV-Visible spectrophotometry and photoluminescence (PL) spectroscopy. Changing pH value from 4.8 to 0.8 decreases the particle size and correspondingly increases the band gap. The PL emission intensity also increases by decreasing the pH values.


NANO ◽  
2016 ◽  
Vol 11 (02) ◽  
pp. 1650023 ◽  
Author(s):  
Lin Ma ◽  
Xiaoping Zhou ◽  
Limei Xu ◽  
Xuyao Xu ◽  
Lingling Zhang

We introduce a two-step hydrothermal and microwave method to prepare novel SnO2/MoS2 composites. The as-prepared samples are well characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). The experimental results indicate that the SnO2/MoS2 composites are composed of MoS2 nanosheets and ultrafine SnO2 nanoparticles with mean size of 3–4[Formula: see text]nm which are well-distributed and anchored on the surface of MoS2 nanosheets. The resultant composites demonstrate prominently improved electrochemical performances, which could be attributed to the unique and robust microstructures and synergetic effect between MoS2 and SnO2.


2014 ◽  
Vol 953-954 ◽  
pp. 1040-1044
Author(s):  
Yang Li ◽  
Jing Li ◽  
Hua Qing Xie

α-MnO2nanowire was prepared by hydrothermal method. The structure of as-prepared manganese oxide demonstrated tetragonal crystalline in X-ray diffraction pattern. Scan electron microscopy (SEM) and Transmission electron microscopy (TEM) revealed the nanowire morphology of as-prepared α-MnO2. The band gap of α-MnO2was estimated at about 2.06 eV via UV-vis spectrum. As the electrode active material for supercapacitor, the electrochemical specific capacitance of α-MnO2nanowire achieved 156.5 F/g, which possessed typical capacitive behaviors and good cycling stabilities. Based on the preferable electrochemical performances, as-synthesized α-MnO2nanowire may be a potential alternative as electrode material for supercapacitor.


Author(s):  
R. Gronsky

The phenomenon of clustering in Al-Ag alloys has been extensively studied since the early work of Guinierl, wherein the pre-precipitation state was characterized as an assembly of spherical, ordered, silver-rich G.P. zones. Subsequent x-ray and TEM investigations yielded results in general agreement with this model. However, serious discrepancies were later revealed by the detailed x-ray diffraction - based computer simulations of Gragg and Cohen, i.e., the silver-rich clusters were instead octahedral in shape and fully disordered, atleast below 170°C. The object of the present investigation is to examine directly the structural characteristics of G.P. zones in Al-Ag by high resolution transmission electron microscopy.


Author(s):  
Vicki L. Baliga ◽  
Mary Ellen Counts

Calcium is an important element in the growth and development of plants and one form of calcium is calcium oxalate. Calcium oxalate has been found in leaf seed, stem material plant tissue culture, fungi and lichen using one or more of the following methods—polarized light microscopy (PLM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and x-ray diffraction.Two methods are presented here for qualitatively estimating calcium oxalate in dried or fixed tobacco (Nicotiana) leaf from different stalk positions using PLM. SEM, coupled with energy dispersive x-ray spectrometry (EDS), and powder x-ray diffraction were used to verify that the crystals observed in the dried leaf with PLM were calcium oxalate.


2002 ◽  
Vol 716 ◽  
Author(s):  
Seok Woo Hong ◽  
Yong Sun Lee ◽  
Ki-Chul Park ◽  
Jong-Wan Park

AbstractThe effect of microstructure of dc magnetron sputtered TiN and TaN diffusion barriers on the palladium activation for autocatalytic electroless copper deposition has been investigated by using X-ray diffraction, sheet resistance measurement, field emission scanning electron microscopy (FE-SEM) and plan view transmission electron microscopy (TEM). The density of palladium nuclei on TaN diffusion barrier increases as the grain size of TaN films decreases, which was caused by increasing nitrogen content in TaN films. Plan view TEM results of TiN and TaN diffusiton barriers showed that palladium nuclei formed mainly on the grain boundaries of the diffusion barriers.


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