scholarly journals A reusable mesoporous adsorbent for efficient treatment of hazardous triphenylmethane dye wastewater: RSM-CCD optimization and rapid microwave-assisted regeneration

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Payam Arabkhani ◽  
Hamedreza Javadian ◽  
Arash Asfaram ◽  
Seyed Nabiollah Hosseini
Keyword(s):  
Sol Gel ◽  
Combustion Process ◽  
Dye Adsorption ◽  
Total Pore Volume ◽  
Moisture Loss ◽  
Maximum Adsorption Capacity ◽  
Homogeneous Surface ◽  
Efficient Treatment ◽  
Triphenylmethane Dye ◽  
Auto Combustion

AbstractIn this research, mesoporous calcium aluminate nanostructures (meso-CaAl2O4) were synthesized using a citric acid-assisted sol–gel auto-combustion process as the potential adsorbent to eliminate toxic triphenylmethane dye malachite green (MG) from synthetic/real effluent. The surface morphology of meso-CaAl2O4 was highly porous with nanometric size and non-homogeneous surface. The specific surface area, total pore volume, and BJH pore diameter of meso-CaAl2O4 were 148.5 m2 g−1, 1.39 cm3 g−1, and 19 nm, respectively. The meso-CaAl2O4 also showed a very high heat resistance, due to losing only 7.95% of its weight up to 800 °C, which is mainly related to the moisture loss. The optimal adsorption conditions were obtained based on response surface methods (RSM)-central composite design (CCD) techniques. The Langmuir isotherm model was used for fitting the adsorption measurements, which presented 587.5 mg g–1 as the maximum adsorption capacity of the dye. The data obtained from the adsorption kinetics model were found to correspond to the pseudo-second-order model. Also, the thermodynamic parameters including enthalpy change (ΔH°), entropy change (ΔS°), and Gibbs free energy change (ΔG°) indicated that MG dye adsorption by the meso-CaAl2O4 was feasible, endothermic, and occurred spontaneously. Furthermore, the meso-CaAl2O4 was regenerated by microwave irradiation under 900 W at 6 min, and the MG dye removal efficiency was remained over 90% after the five cycles of microwave regeneration.

INFLUENCE OF pH ON PHYSICAL PROPERTIES OF NICKEL-ZINC NANOCRYSTALLINE POWDERS SYNTHESIZED BY A SOL-GEL AUTO-COMBUSTION METHOD

2008 ◽  
Vol 22 (18n19) ◽  
pp. 3153-3158 ◽  
Author(s):  
M. R. BARATI ◽  
S. A. SEYYED EBRAHIMI ◽  
A. BADIEI
Keyword(s):  
Crystallite Size ◽  
Zinc Ferrite ◽  
Ph Value ◽  
Sol Gel ◽  
Combustion Process ◽  
Nanocrystalline Powders ◽  
Nanocrystalline Powder ◽  
Nickel Zinc ◽  
Auto Combustion ◽  
Influence Of Ph

In this research a sol-gel auto-combustion route has been proposed to synthesize nickel-zinc ferrite nanocrystalline powder, using metal nitrates, citric acid as fuel and ammonia as pH adjusting agent. The influence of pH value of the solution on phase evolution, crystallite size and morphology of as-burnt powders were investigated by XRD, SEM and TEM techniques. The results revealed that with pH=7 the single phase nickel-zinc ferrite nanocrystalline powders with crystallite size of about 27nm were formed directly after auto combustion process.

IMPROVED MAGNETIC PROPERTIES OF Sm COMBINING Co OR/AND Zn SUBSTITUTED BARIUM M-TYPE HEXAFERRITES

2012 ◽  
Vol 26 (26) ◽  
pp. 1250141 ◽  
Author(s):  
Y. B. HAN ◽  
J. SHA ◽  
L. N. SUN ◽  
Q. TANG ◽  
Q. LU ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Phase Composition ◽  
Magnetocrystalline Anisotropy ◽  
Sol Gel ◽  
Combustion Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Barium Hexaferrites ◽  
Auto Combustion ◽  
Magnetic Dilution

Sm (Co or/and Zn) substituted nanocrystalline barium hexaferrites were synthesized by the sol–gel auto-combustion process, then X-ray diffraction (XRD) and vibrating sample magnetometer (VSM) were used to characterize and discuss the phase composition and the magnetic properties of the as-prepared barium hexaferrites. All results showed that the phase composition and magnetic properties were closely related to the doping elements and x. Owing to hyperfine field, canting spin, magnetic dilution and impurity phases, the saturation magnetization (Ms) of all samples increased firstly, and then decreased. Considering the crystallization, the magnetocrystalline anisotropy and the ions occupancy, the doping elements and x critically affected the coercivity (Hc). Compared the magnetic properties of all the samples, it is concluded that Zn 2+ and Co 2+ influenced each other and Zn 2+ occupied 4f2 sites prior to Co 2+, which led to the increase of Ms and the decrease of Hc.

Facile Synthesis and Microwave-Absorption Properties of Organic–Inorganic CoFe2O4/Polyaniline Nanocomposites with Embedded Structure

2020 ◽  
Vol 20 (3) ◽  
pp. 1756-1764 ◽  
Author(s):  
Peng Chen ◽  
Lin-Wen Jiang ◽  
Shan-Shan Yang ◽  
Hong-Bing Chen ◽  
Jun He ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Oxidative Polymerization ◽  
Sol Gel ◽  
Combustion Process ◽  
Interfacial Polarization ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Auto Combustion ◽  
Embedded Structure

Organic–inorganic CoFe2O4/polyaniline (CoFe2O4/PA) nanocomposites with embedded structures were synthesized by combining the sol–gel auto-combustion process and in-situ oxidative polymerization. The phases and morphologies of the prepared samples were identified. The pure CoFe2O4 samples exhibited inferior microwave-absorption properties in a frequency range of 2–18 GHz. Upon the incorporation of PA, the formed CoFe2O4/PA nanocomposites exhibited rather good absorption performances. When the sample thickness was 2.5 mm, the maximum reflection loss (RL) reached -22.3 dB, while the RL below -10 dB corresponded to the range of 11.0–17.1 GHz, which contains almost the entire Ku-band, making the structure promising for commercial and military applications. A physical model was employed to explain the effects of the embedded structure on the microwave-absorption performances. The excellent microwave-absorption performances could be attributed to the interfacial polarization and repeated reflection of the microwaves inside the CoFe2O4/PA composite.

scholarly journals Structural, impedance and Mössbauer studies of magnesium ferrite synthesized via sol–gel auto-combustion process

2017 ◽  
Vol 21 (8) ◽  
pp. 899-910 ◽  
Author(s):  
Shahid Khan Durrani ◽  
Sumaira Naz ◽  
Mazhar Mehmood ◽  
Muhammad Nadeem ◽  
Muhammad Siddique
Keyword(s):  
Sol Gel ◽  
Combustion Process ◽  
Magnesium Ferrite ◽  
Mössbauer Studies ◽  
Auto Combustion

Synthesis and Dielectric Property of Perovskite-Type LaMnO3 Nanoparticle

2007 ◽  
Vol 121-123 ◽  
pp. 967-970 ◽  
Author(s):  
Jie Sun ◽  
Zhen Hua Zhang ◽  
Xiao Hui Cao
Keyword(s):  
Dielectric Property ◽  
Dielectric Loss ◽  
Sol Gel ◽  
Combustion Process ◽  
Chelating Agent ◽  
Combustion Method ◽  
Auto Combustion ◽  
Ft Ir ◽  
Dielectric Coefficient ◽  
Perovskite Type

The perovskite-type nanocrystal LaMnO3 was prepared using sol-gel auto-combustion method with citric acid as the chelating agent. Some analytical methods consisted of FT-IR, XRD, TEM and wave-guide method were used to characterize the gel and the final products. The metal ions coordination compound, obtained from nitrate and citrate, underwent an auto-combustion process and voluminous ashes formed when calcining the complex in the air. From the result of the dielectric properity. It was shown that the dielectric coefficient curves and dielectric loss curve of LaMnO3 nanocrystals were smooth in the range of 8-11MHz. The dielectric loss can be obversed obviously in the measured range.

scholarly journals Effect of Al3+ Substitution On Magnetic and DC Electrical Resistivity Properties of NiZnCu Nanoferrites

2021 ◽  
Author(s):  
N MURALI
Keyword(s):  
Electrical Resistivity ◽  
Negative Temperature Coefficient ◽  
Sol Gel ◽  
Combustion Process ◽  
Negative Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Auto Combustion ◽  
Ft Ir ◽  
Resultant Material

Abstract Al substituted Ni0.4Zn0.35Cu0.25Fe2-xAlxO4 (x = 0.00, 0.05, 0.10, 0.15, 0.20) samples is synthesized using the sol-gel auto-combustion process. X-ray diffraction shows its cubic spinel structure. The lattice constant decreases as the Al3+ content increases. The sizes of the crystallites are also decreasing in the range of 32.15 nm to 22.89 nm. The wavenumbers of tetrahedral and octahedral sites sighted in the FT-IR spectra are similar to that of the precursor. The increment in the Al3+ content increases the DC conductivity. The electrical resistivity decrease with an increase in the temperature, i.e., it has a negative temperature coefficient with resistance similar to semiconductors. VSM results show their isotropic nature forming single domain ferrimagnetic particles. The resultant material is widely significant, as indicated by its result.

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