scholarly journals Preparation of Magnetic g-C3N4/Fe3O4 Composite and Its Application in the Separation of Catechol from Water

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2844 ◽  
Author(s):  
Ruilan Xu ◽  
Yong Peng
Keyword(s):  
Ph Value ◽  
Removal Rate ◽  
Practical Significance ◽  
Adsorption Parameters ◽  
Adsorption Models ◽  
The Matrix ◽  
Co Precipitation ◽  
Adsorption Desorption ◽  
First Time ◽  
The Magnetic Field

Catechol has strong toxicity and deformity as well as carcinogenicity, and it is difficult to degrade naturally. Therefore, it is of great practical significance to develop efficient adsorbents to separate catechol from water quickly and effectively. In this work, g-C3N4/Fe3O4 magnetic nanocomposites were prepared using g-C3N4 as the matrix by chemical co-precipitation, mixing with Fe2+ and Fe3+ solutions. Then, g-C3N4/Fe3O4 was used, for the first time, as an adsorbent to investigate the removal rate of catechol under different conditions by the magnetic field separation method. The adsorption parameters of the g-C3N4/Fe3O4 nanocomposite were evaluated by the Langmuir and Freundlich adsorption models. The results showed that the g-C3N4/Fe3O4 nanocomposite presented a two-step adsorption behavior and a considerably high adsorption capacity. The removal rate of catechol reached 70% at the dosage of 50 mg, adsorption time of 30 min, and pH value of 6. Five adsorption–desorption cycles demonstrated that the g-C3N4/Fe3O4 material had good stability and reusability.

scholarly journals Lignocellulose@ Activated Clay Nanocomposite with Hierarchical Nanostructure Enhancing the Removal of Aqueous Zn(II)

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1710 ◽  
Author(s):  
Xiaotao Zhang ◽  
Yinan Hao ◽  
Zhangjing Chen ◽  
Yuhong An ◽  
Wanqi Zhang ◽  
...  
Keyword(s):  
Ph Value ◽  
Removal Rate ◽  
Weight Ratio ◽  
Order Kinetic ◽  
Adsorption Parameters ◽  
Hierarchical Nanostructure ◽  
Desorption Temperature ◽  
Desorption Time ◽  
Adsorption Temperature ◽  
Hcl Concentration

A lignocellulose@ activated clay (Ln@AC) nanocomposite with a hierarchical nanostructure was successfully synthesized by the chemical intercalation reaction and applied in the removal of Zn(II) from an aqueous solution. Ln@AC was characterized by N2 adsorption/desorption isotherms and X-Ray Diffraction (XRD), scanning Electron Microscope (SEM), transmission Electron Microscopy (TEM) and Fourier Transform Infrared Spectroscopy (FTIR) analysis, and the results indicate that an intercalated–exfoliated hierarchical nanostructure was formed. The effects of different adsorption parameters on the Zn(II) removal rate (weight ratio of Ln to AC, Ln@AC dosage, initial Zn(II) concentration, pH value, adsorption temperature, and time) were investigated in detail. The equilibrium adsorption capacity reached 315.9 mg/g under optimal conditions (i.e., the weight ratio of Ln to AC of 3:1, Ln@AC dosage of 1 g/L, initial Zn(II) concentration of 600 mg/L, pH value of 6.8, adsorption temperature of 65 °C, and adsorption time of 50 min). The adsorption process was described by the pseudo-second-order kinetic model, Langmuir isotherm model, and the Elovich model. Moreover, Zn(II) could be easily eluted by HCl, and the effects of HCl concentration, desorption temperature, and ultrasonic desorption time on desorbed amount were tested. Desorption studies revealed that with an HCl concentration of 0.25 mol/L, desorption temperature of 70 °C, and ultrasonic desorption time of 20 min, the maximum desorption capacity and efficiency were achieved at 202.5 mg/g and 64.10%, respectively. Regeneration experimental results indicated that the Ln@AC exhibited a certain recyclable regeneration performance. Due to such outstanding features, the novel Ln@AC nanocomposite proved to have great adsorption potential for Zn(II) removal from wastewater, and exhibited an extremely significant amount of adsorbed Zn(II) when compared to conventional adsorbents.

Nanoparticle Fe3O4 magnetized activated carbon from Armeniaca sibirica shell for the adsorption of Hg(II) ions

BioResources ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. 6100-6120
Author(s):  
Yinan Hao ◽  
Yanfei Pan ◽  
Qingwei Du ◽  
Xudong Li ◽  
Ximing Wang
Keyword(s):  
Activated Carbon ◽  
Adsorption Capacity ◽  
Ph Value ◽  
Removal Rate ◽  
Freundlich Isotherm ◽  
Entropy Change ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Adsorption Parameters ◽  
Initial Concentration

Armeniaca sibirica shell activated carbon (ASSAC) magnetized by nanoparticle Fe3O4 prepared from Armeniaca sibirica shell was investigated to determine its adsorption for Hg2+ from wastewater. Fe3O4/ASSAC was characterized using XRD (X-ray diffraction), FTIR (Fourier transform infrared spectroscopy), SEM (scanning electron microscopy), and BET (Brunauer–Emmett–Teller). Optimum adsorption parameters were determined based on the initial concentration of Hg2+, reaction time, reaction temperature, and pH value in adsorption studies. The experiment results demonstrated that the specific surface area of ASSAC decreased after magnetization; however the adsorption capacity and removal rate of Hg2+ increased 0.656 mg/g and 0.630%, respectively. When the initial concentration of Hg2+ solution was 250 mg/L and the pH value was 2, the adsorption time was 180 min and the temperature was 30 °C, and with the Fe3O4/ASSAC at 0.05 g, the adsorption reaching 97.1 mg/g, and the removal efficiency was 99.6%. The adsorption capacity of Fe3O4/ASSAC to Hg2+ was in accord with Freundlich isotherm models, and a pseudo-second-order kinetic equation was used to fit the adsorption best. The Gibbs free energy ΔGo < 0，enthalpy change ΔHo < 0, and entropy change ΔSo < 0 which manifested the adsorption was a spontaneous and exothermic process.

Preparation of Xonotlite Whiskers from Carbide Slag

2010 ◽  
Vol 434-435 ◽  
pp. 787-789
Author(s):  
Fei Liu ◽  
Ling Ke Zeng ◽  
Jian Xin Cao ◽  
Qian Lin ◽  
Jing Li
Keyword(s):  
Ph Value ◽  
Raw Materials ◽  
Removal Rate ◽  
Hydrothermal Conditions ◽  
Hydrothermal Route ◽  
Synthesis Conditions ◽  
Ph Values ◽  
Carbide Slag ◽  
Xrd Techniques ◽  
First Time

Carbide slag was used as raw materials for the first time to prepare xonontlite whiskers via a hydrothermal route without special instruments and synthesis conditions. And the effect of pH value of emulsion of carbide slag and hydrothermal conditions on removal rate of impurities, morphology and crystallinity of synthesized xonotlite whiskers were explored using ICP, SEM and XRD techniques. The results indicated that the carbide slag after purification could be used to prepare xonotlite whiskers, and different pH values of emulsion of carbide slag had great impact on the removal rate of impurities and morphology of xonotlite whiskers. Xonotlite whiskers with 20-40 μm in length and 100-500 nm in diameter were hydrothermally synthesized at 230 °C for 15 h with using silicic acid as kiesel material.

scholarly journals Facile synthesis of a high purity α-MnO2 nanorod for rapid degradation of Rhodamine B

2021 ◽  
Author(s):  
shumin wang ◽  
Ao Guan ◽  
Jiahan Wang ◽  
Xiaofang Fu ◽  
Xiang Guo ◽  
...  
Keyword(s):  
Rhodamine B ◽  
High Efficiency ◽  
Catalytic Mechanism ◽  
Ph Value ◽  
Removal Rate ◽  
Precipitation Method ◽  
Characteristic Peak ◽  
Catalytic Stability ◽  
Rapid Removal ◽  
Co Precipitation

Abstract Manganese dioxide (α-MnO2) nanorods with diameters of about 5-15 nm and lengths of 100-150 nm were synthesized by a simple co-precipitation method. XRD, TEM, HRTEM, SAED and XPS were used to analyze the crystallographic information, microstructure and chemical bonding of the as-prepared sample. The α-MnO2 nanorod exhibited a high efficiency and rapid removal rate of rhodamine B (RhB), which reached about 97.5% within 10 min when pH=4 (and pH=6.6) and 97.7% within 50 min when pH = 9 in the presence of H2O2. The results also indicated that a lower pH value is conducive to the movement of the characteristic peak and the attenuation of the intensity of the characteristic peak of RhB dye. Then a possible catalytic mechanism was revealed. Moreover, the α-MnO2 nanorod exhibits an excellent recyclability and catalytic stability. This research indicates that α-MnO2 nanorods have a potential application in practical dye pollutant treatment.

The adsorption of Sb(III) in aqueous solution by Fe2O3-modified carbon nanotubes

2013 ◽  
Vol 68 (3) ◽  
pp. 658-664 ◽  
Author(s):  
Tingchao Yu ◽  
Chao Zeng ◽  
Miaomiao Ye ◽  
Yu Shao
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Aqueous Solution ◽  
Ph Value ◽  
Removal Rate ◽  
Nitrogen Adsorption ◽  
Solution Ph ◽  
Freundlich Adsorption Isotherm ◽  
Modified Carbon Nanotubes ◽  
Adsorption Desorption

A novel kind of iron oxide supported on carbon nanotubes (CNTs) was prepared for adsorption of antimony (Sb)(III) in aqueous solution. The iron (III) oxide (Fe2O3)-modified CNTs were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, nitrogen adsorption–desorption and Fourier transform infrared spectrometer. Parameters affecting the adsorption efficiencies, including solution pH value, initial Sb(III) concentration, adsorbent dosage, adsorption time and temperature, were investigated. The results indicate that the removal rate of Sb(III) by Fe2O3-modified CNTs is 99.97% under the initial Sb(III) concentration of 1.5 mg/L, adsorbents dosage of 0.5 g/L, temperature of 25 oC and pH value of 7.00, which is 29.81% higher than that of the raw CNTs. The adsorption capacity increased correspondingly from 3.01 to 6.23 mg/g. The equilibrium adsorption data can be fitted to the Freundlich adsorption isotherm. In addition, it has been found that the solution pH values and adsorption temperatures have no significant influence on Sb(III) removal.

Performance Research on Aniline Adsorption from Aqueous Solution by Modified Zeolite/EPDM Composite

2012 ◽  
Vol 571 ◽  
pp. 73-76
Author(s):  
Xiu Qi Liu ◽  
He Qin Xing ◽  
Hong Chen ◽  
Jia Tong Liu
Keyword(s):  
Natural Zeolite ◽  
Ph Value ◽  
Removal Rate ◽  
Influential Factors ◽  
Melt Blending ◽  
Adsorption Time ◽  
Initial Concentration ◽  
Ph Values ◽  
The Matrix ◽  
Performance Research

In this study, a new composite was prepared for aniline adsorption by melt blending with EPDM as the matrix and natural zeolite was modified by microwave as the filler. The properties and some influential factors of composite for adsorption of aniline in the solutions were experimentally investigated, such as composite dosage, adsorption time and pH values. The results showed that in the case of the initial concentration of the aniline wastewater was 50mg/L, when the use level of composite was 1 g, pH value was 1, and the oscillating adsorption time was 2 h, the removal rate could be up to 92%.

Soil and Stream Water Chemistry During Spring Snowmelt

1992 ◽  
Vol 23 (1) ◽  
pp. 13-26 ◽  
Author(s):  
W. H. Hendershot ◽  
L. Mendes ◽  
H. Lalande ◽  
F. Courchesne ◽  
S. Savoie
Keyword(s):  
Stream Water ◽  
Base Cations ◽  
Stream Chemistry ◽  
Stream Water Chemistry ◽  
The Matrix ◽  
Adsorption Desorption ◽  
The Relationship ◽  
Best Fit ◽  
Spring Snowmelt ◽  
Over Time

In order to determine how water flowpath controls stream chemistry, we studied both soil and stream water during spring snowmelt, 1985. Soil solution concentrations of base cations were relatively constant over time indicating that cation exchange was controlling cation concentrations. Similarly SO4 adsorption-desorption or precipitation-dissolution reactions with the matrix were controlling its concentrations. On the other hand, NO3 appeared to be controlled by uptake by plants or microorganisms or by denitrification since their concentrations in the soil fell abruptly as snowmelt proceeded. Dissolved Al and pH varied vertically in the soil profile and their pattern in the stream indicated clearly the importance of water flowpath on stream chemistry. Although Al increased as pH decreased, the relationship does not appear to be controlled by gibbsite. The best fit of calculated dissolved inorganic Al was obtained using AlOHSO4 with a solubility less than that of pure crystalline jurbanite.

Nano-ZrO2/TiO2 Impregnated Orange Wood Sawdust and Peach Stone Shell Adsorbents for Cr (VI) Removal

2020 ◽  
Vol 16 (7) ◽  
pp. 880-892
Author(s):  
Şerife Parlayıcı ◽  
Kübra Tuna Sezer ◽  
Erol Pehlivan
Keyword(s):  
Contact Time ◽  
Ph Value ◽  
Order Kinetic ◽  
Adsorption Parameters ◽  
Wood Sawdust ◽  
Adsorption Data ◽  
Langmuir Isotherm Model ◽  
Pseudo Second Order ◽  
Ft Ir ◽  
Equilibrium Status

Background: In this work, Cr (VI) adsorption on nano-ZrO2๏TiO2 impregnated orange wood sawdust (Zr๏Ti/OWS) and nano-ZrO2๏TiO2 impregnated peach stone shell (Zr๏Ti/PSS) was investigated by applying different adsorption parameters such as Cr (VI) concentrations, contact time, adsorbent dose, and pH for all adsorbents. Methods: The adsorbents were characterized by SEM and FT-IR. The equilibrium status was achieved after 120 min of contact time and optimum pH value around 2 were determined for Cr (VI) adsorption. Adsorption data in the equilibrium is well-assembled by the Langmuir model during the adsorption process. Results: Langmuir isotherm model showed a maximum adsorption value of OWS: 21.65 mg/g and Zr๏Ti/OWS: 27.25 mg/g. The same isotherm displayed a maximum adsorption value of PSS: 17.64 mg/g, and Zr๏Ti/PSS: 31.15 mg/g. Pseudo-second-order kinetic models (R2=0.99) were found to be the best models for describing the Cr (VI) adsorption reactions. Conclusıon: Thermodynamic parameters such as changes in ΔG°, ΔH°, and ΔS° have been estimated, and the process was found to be spontaneous.

Adsorption of safranine T from aqueous medium by nano mesoporous MCM-41: adsorption equilibrium, kinetics, and thermodynamics

2020 ◽  
Vol 10 ◽  
Author(s):  
Xiao-Dong Li ◽  
Qing-Zhou Zhai
Keyword(s):  
Electron Microscopy ◽  
Ph Value ◽  
Particle Diameter ◽  
Spherical Particles ◽  
Practical Significance ◽  
Average Particle ◽  
Average Pore ◽  
Kinetics And Thermodynamics ◽  
Safranine T ◽  
Mcm 41

Introduction: In industrial production, a small amount of saffron T emissions will cause increase of water color and increase of chemical oxygen consumption, so study of the decolorization of saffron T wastewater has an important practical significance. Methods: MCM (Mobil Composition of Matter)-41 molecular sieve was synthesized by hydrothermal method. Power Xray diffraction and scanning electron microscopy were used to characterize the sample. Safranine T dye was adsorbed from water by the MCM-41 prepared. Kinetics and thermodynamics of the adsorption were studied. Results: The MCM-41 sample presented spherical particles and regular. The BET (Brunner-Emmett-Teller) specific surface area of the sample determined by 77 K low temperature nitrogen adsorption-desorption isotherm was 932 m2 /g. Its average particle diameter was 110 nm. TEM (transmission electron microscopy) results showed that the sample structure presented a honeycomb pore structure and the average pore diameter was 3.0 nm. The results showed that when room temperature was 20 ± 1 ℃, adsorbate safranine T: adsorbent MCM-41 = 20 : 1，the optimum pH value of adsorption was 4.0 and contact time was 20 min, the adsorption rate reached 98.29% and the adsorption capacity was 19.66 mg/g. The entropy change and enthalpy change of the adsorption system are respectively ΔS0 = 157.5 J/(mol·K); ΔH0 = 21.544 kJ/mol. When temperature was 277.15, 293.15, 303.15 K，the free energy change was respectively △G1 0 = -22.107 kJ/mol, △G2 0 = -24.627 kJ/mol, △G3 0 = -26.202 kJ/mol. Conclusion: The adsorption of safranine T by MCM-41 belongs to a pseudo-second-order adsorption. This adsorption accords with the Freundlich equation and belongs to a heterogeneous adsorption. The adsorption is an endothermic reaction of entropy increase, being spontaneous.

scholarly journals Extraction and Mass Spectrometric Characterization of Terpenes Recovered from Olive Leaves Using a New Adsorbent-Assisted Supercritical CO2 Process

Foods ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1301
Author(s):  
Zully J. Suárez Montenegro ◽  
Gerardo Álvarez-Rivera ◽  
Jose A. Mendiola ◽  
Elena Ibáñez ◽  
Alejandro Cifuentes
Keyword(s):  
Aluminum Oxide ◽  
Silica Gel ◽  
Supercritical Co2 ◽  
Olive Leaves ◽  
Fractionation Process ◽  
Selective Enrichment ◽  
Adsorption Desorption ◽  
First Time ◽  
By Products

This work reports the use of GC-QTOF-MS to obtain a deep characterization of terpenoid compounds recovered from olive leaves, which is one of the largest by-products generated by the olive oil industry. This work includes an innovative supercritical CO2 fractionation process based on the online coupling of supercritical fluid extraction (SFE) and dynamic adsorption/desorption for the selective enrichment of terpenoids in the different olive leaves extracts. The selectivity of different commercial adsorbents such as silica gel, zeolite, and aluminum oxide was evaluated toward the different terpene families present in olive leaves. Operating at 30 MPa and 60 °C, an adsorbent-assisted fractionation was carried out every 20 min for a total time of 120 min. For the first time, GC-QTOF-MS allowed the identification of 40 terpenoids in olive leaves. The GC-QTOF-MS results indicate that silica gel is a suitable adsorbent to partially retain polyunsaturated C10 and C15 terpenes. In addition, aluminum oxide increases C20 recoveries, whereas crystalline zeolites favor C30 terpenes recoveries. The different healthy properties that have been described for terpenoids makes the current SFE-GC-QTOF-MS process especially interesting and suitable for their revalorization.

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