scholarly journals Nanostructure Design and Catalytic Performance of Mo/ZnAl-LDH in Cationic Orchid X-BL Removal

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2390 ◽  
Author(s):  
Yin Xu ◽  
Tingjiao Liu ◽  
Yang Li ◽  
Yun Liu ◽  
Fei Ge
Keyword(s):  
Catalytic Activity ◽  
Removal Efficiency ◽  
Room Temperature ◽  
Sol Gel ◽  
Catalytic Performance ◽  
Air Oxidation ◽  
Preparation Methods ◽  
Temperature And Pressure ◽  
Co Precipitation ◽  
Double Hydroxide

The nanostructure of ZnAl-layered double hydroxide (ZnAl-LDH) was designed to promote the catalytic performance of Mo-based ZnAl-LDH (Mo/ZnAl-LDH) catalysts, in a catalytic wet air oxidation (CWAO) process, under room temperature and pressure, in degradation of dye wastewater. Four most commonly used preparation methods, traditional precipitation (TP), hydrothermal synthesis (HS), sol-gel (SG), and urea co-precipitation (UC) were employed to prepare the ZnAl-LDH. The resulting Mo/ZnAl-LDH samples were contrasted through surface area, crystal structure, chemical state, and morphology. The degradation of cationic orchid X-BL, under room temperature and pressure, was developed to determine the catalytic activity of these Mo/ZnAl-LDH samples. The results showed that the nanostructure of ZnAl-LDH, prepared by HS, enhanced the adhesion of the catalytic active component, thus Mo/ZnAl-LDH had the highest catalytic activity of 84.2% color removal efficiency and 73.9% total organic carbon removal efficiency. Specific Mo species, such as Na2Mo2O7, Mo dispersion, and O2− ions were proved to be related with catalytic performance. These findings preliminarily clarified that LDHs preparation methods make a difference in the performance of Mo/LDHs.

Nickel (II) and oxovanadium (IV) complexes supported on MCM-41 mesoporous and their application in catalytic selective sulfide and thiol oxidation

2020 ◽  
Vol 23 ◽  
Author(s):  
Mohsen Nikoorazm ◽  
Maryam Khanmoradi ◽  
Masoumeh Sayadian
Keyword(s):  
Catalytic Activity ◽  
Room Temperature ◽  
Sol Gel ◽  
Reaction Times ◽  
Significant Loss ◽  
Spectral Studies ◽  
High Catalytic Activity ◽  
Catalytic Systems ◽  
Solvent Free Conditions ◽  
Mcm 41

Introduction:: MCM-41 was synthesized using the sol-gel method. Then two new transition metal complexes of Nickel (II) and Vanadium (IV), were synthesized by immobilization of adenine (6-aminopurine) into MCM-41 mesoporous. The compounds have been characterized by XRD, TGA, SEM, AAS and FT-IR spectral studies. Using these catalysts provided an efficient and enantioselective procedure for oxidation of sulfides to sulfoxides and oxidative coupling of thiols to their corresponding disulfides using hydrogen peroxide at room temperature. Materials and Methods:: To a solution of sulfide or thiol (1 mmol) and H2O2 (5 mmol), a determined amount of the catalyst was added. The reaction mixture was stirred at room temperature for the specific time under solvent free conditions. The progress of the reaction was monitored by TLC using n-hexane: acetone (8:2). Afterwards, the catalyst was removed from the reaction mixture by centrifugation and, then, washed with dichloromethane in order to give the pure products. Results:: All the products were obtained in excellent yields and short reaction times indicating the high activity of the synthesized catalysts. Besides, the catalysts can be recovered and reused for several runs without significant loss in their catalytic activity. Conclusion:: These catalytic systems furnish the products very quickly with excellent yields and VO-6AP-MCM-41 shows high catalytic activity compared to Ni-6AP-MCM-41.

Effect of Preparation Methods of HPW/SiO2 Mesoporous Composites on its Catalytic Performance in Fuel Oils Desulfurization

2010 ◽  
Vol 148-149 ◽  
pp. 924-928
Author(s):  
Xue Min Yan ◽  
Yuan Zhu Mi
Keyword(s):  
Catalytic Activity ◽  
Self Assembly ◽  
Electrostatic Force ◽  
Oxidative Desulfurization ◽  
Strong Acid ◽  
Catalytic Performance ◽  
Synthesis Mechanism ◽  
Base Interaction ◽  
Preparation Methods ◽  
Oh Groups

Two kinds of mesoporous HPW/SiO2 composites, which have been synthesized respectively by the amino-functionalized (AF) method and evaporation-induced self-assembly (EISA) method, have been used as catalysts in the oxidative desulfurization process of dibenzothiophene(DBT). The catalytic performance results show that the catalyst synthesized by EISA method holds higher catalytic activity than that synthesized by the AF method. The difference of catalytic activity can be attributed to the different synthesis mechanism of two kinds of composites. In the AF method, the bonding force between HPW and SiO2 is strong acid-base interaction, which damages the Keggin structure. Whereas in the EISA process, electrostatic force and hydrogen bonds between W=O groups and Si-OH groups are main bonding forces. The hydrogen bond holds the electron-withdrawing effect, which increases the activity of nonbonding W=O groups in HPW and then results in the enhancement of the catalytic activity.

How does the Support Influence the Catalytic Activity of the Keggin Ion?

1996 ◽  
Vol 454 ◽  
Author(s):  
Zakiyyah Smith ◽  
Michael Palmieri ◽  
Nancy Buecheler ◽  
Susan A. Jansen
Keyword(s):  
Catalytic Activity ◽  
Carbon Materials ◽  
Solid Acid ◽  
Sol Gel ◽  
Catalytic Performance ◽  
Heteropoly Acids ◽  
Keggin Ion ◽  
Oxide Substrates ◽  
Silica Matrices

AbstractHeteropoly acids, HPA are well known solid acid and oxidation catalysts that find application in hetergeneous and homogeneous reactions. In the former, surface area and stability problems are diminshed by supporting the HPA. Typical supports include oxide substrates and porous carbon materials. The HPA's show some instability on these supports however. In this work, we demonstrate that HPA encapsulated in sol-gel silica matrices show enhanced catalytic performance without compromising the catalytic activity of the HPA. In addition, the specific role of the support in the catalytic process is described as well.

Deep Oxidative Desulfurization of Dibenzothiophene by Functional Tungsten-Containing Mesoporoussilica from Polyoxometalate-Based Salts

2014 ◽  
Vol 636 ◽  
pp. 93-96
Author(s):  
Ming Zhang ◽  
Wen Shuai Zhu ◽  
Meng Li ◽  
Yan An Li ◽  
Suhang Xun ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Organic Solvents ◽  
Room Temperature ◽  
Oxidative Desulfurization ◽  
Catalytic Performance ◽  
Sulfur Compounds ◽  
High Dispersion ◽  
One Pot ◽  
Tungsten Species

Tungsten-containing functional mesoporousW-SiO2 have been successfully synthesized by an one-pot and facile room-temperature procedure. These materials presented a high dispersion of tungsten species and excellent catalytic activity on the removal of sulfur compounds without any organic solvents as extractants. The catalytic performance on sulfur compounds was investigated in detail. After recycling for 8 times, the removal of the oxidation desulfurization system could still reach 92.0%.

scholarly journals Fabrication of Core-Shell Structural SiO2@H3[PM12O40] Material and Its Catalytic Activity

2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
Xin Yang ◽  
Junhai Wang ◽  
Qi Zhang ◽  
Xu Wang ◽  
Linlin Xu ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Heterogeneous Catalysts ◽  
Sol Gel ◽  
Operating Conditions ◽  
Core Shell ◽  
Catalytic Wet Air Oxidation ◽  
Air Oxidation ◽  
Wet Air Oxidation ◽  
Heterogeneous Catalytic ◽  
Room Condition

Through a natural tree grain template and sol-gel technology, the heterogeneous catalytic materials based on polyoxometalate compounds H3[PM12O40] encapsulating SiO2: SiO2@H3[PM12O40] (SiO2@PM12, M = W, Mo) with core-shell structure had been prepared. The structure and morphology of the core-shell microspheres were characterized by the XRD, IR spectroscopy, UV-Vis absorbance, and SEM. These microsphere materials can be used as heterogeneous catalysts with high activity and stability for catalytic wet air oxidation of pollutant dyes safranine T (ST) at room condition. The results show that the catalysts have excellent catalytic activity in treatment of wastewater containing 10 mg/L ST, and 94% of color can be removed within 60 min. Under different cycling runs, it is shown that the catalysts are stable under such operating conditions and the leaching tests show negligible leaching effect owing to the lesser dissolution.

Effect of Ni/Co Ratio on Bimetallic Oxide Supported Silica Catalyst in CO2 Methanation

2015 ◽  
Vol 802 ◽  
pp. 431-436
Author(s):  
Siti Aminah Md Ali ◽  
Ku Halim Ku Hamid ◽  
Kamariah Noor Ismail
Keyword(s):  
Catalytic Activity ◽  
Fixed Bed ◽  
Catalytic Performance ◽  
Fixed Bed Reactor ◽  
Wet Impregnation ◽  
Co Precipitation

Five series of silica supported bimetallic oxide (NiCo/SiO2) catalysts have been synthesized through successive reverse co-precipitation and wet impregnation methods at different metal loadings (i.e. 80Ni20Co/SiO2,, 60Ni40Co/SiO2,50Ni50Co/SiO2,40Ni60Co/SiO2,20Ni80Co/SiO2). The catalytic performance of these catalysts were tested for the CO2methanation catalysis using microactivity fixed bed reactor. Nickel rich catalyst (80Ni20Co/SiO2) exhibited the highest catalytic activity in the CO2methanation with 47.1% of CO2conversion. Meanwhile, the CH4selectivity and yield was found to be at 99.9% and 27%, respectively.

scholarly journals Lanthanum-Based Perovskite-Type Oxides La1−xCexBO3(B = Mn and Co) as Catalysts: Synthesis and Characterization

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Nyamdavaa Erdenee ◽  
Uyanga Enkhnaran ◽  
Sevjidsuren Galsan ◽  
Altantsog Pagvajav
Keyword(s):  
Catalytic Activity ◽  
Sol Gel ◽  
Catalytic Performance ◽  
Reduction Behavior ◽  
Process Characterization ◽  
Lattice Geometry ◽  
Sol Gel Process ◽  
Ce Substitution ◽  
Crystallite Sizes ◽  
Perovskite Type

La1−xCexCoO3(x= 0, 0.2, 0.4) and La1−xCexMnO3(x= 0, 0.2) perovskite-type oxides were prepared by sol-gel process. Characterization techniques EDS, FTIR, XRD, BET, and XPS experiments were performed to survey the composition, bulk structure, and the surface properties of perovskites. The reduction behavior, thermal stability, and catalytic activity were studied by H2-TPR and catalytic performance. All synthesized samples showed well crystalline perovskite structure, 8–22 nm crystallite sizes, and SSA with 2–27 m2 g−1. The XRD results showed that the Ce substitution promoted the structural transformation for LaCoO3from rhombohedral into cubic and for LaMnO3no change in lattice geometry. Substitution with cerium (x= 0.2) showed smaller crystallite size, higher SSA, and the highest reducibility and catalytic activity for LaCoO3.

Destruction of EDTA by Bimetallic Al-Fe/O2 Process under Aqueous Room Temperature and Pressure Conditions

2013 ◽  
Vol 800 ◽  
pp. 555-559
Author(s):  
Xin Liu ◽  
Jin Hong Fan ◽  
Lu Ming Ma
Keyword(s):  
Aqueous Solution ◽  
Benzoic Acid ◽  
Removal Efficiency ◽  
Room Temperature ◽  
Ethylenediaminetetraacetic Acid ◽  
Oxidative Degradation ◽  
Hydroxybenzoic Acid ◽  
Mass Ratio ◽  
Initial Ph ◽  
Temperature And Pressure

Oxidative degradation of ethylenediaminetetraacetic acid (EDTA) in aqueous solution at room temperature and pressure by the bimetallic Al-Fe/O2 process, which was verified by the addition of benzoic acid as ·OH scavenger and the detection of para-hydroxybenzoic acid, was investigated. The results showed that the removal efficiency of EDTA, TOC and TN could be about 98%, 77.5% and 43% respectively after 3h reaction when the initial pH was 5. The effects of initial pH, concentration of EDTA, mass ratio of Al0 and Fe0 and Al-Fe loading were also investigated. Significantly, the bimetallic Al-Fe process exhibited higher reactivity than monometallic Fe0/Al0 process for the degradation of EDTA when the mass ratio of Al0 and Fe0 ranged from 0.11 to 2.97.

scholarly journals Comparison of the photocatalytic efficacy and environmental impact of CdS, ZnFe2O4, and NiFe2O4 under visible light irradiation

2021 ◽  
Vol 83 (5) ◽  
pp. 993-1004
Author(s):  
Xiaoyu Wang ◽  
Susan J. Masten ◽  
Elaheh Esfahanian
Keyword(s):  
Environmental Impact ◽  
Visible Light ◽  
Hydrothermal Method ◽  
Life Cycle Analysis ◽  
Room Temperature ◽  
Catalyst Surface ◽  
Sol Gel ◽  
Aqueous Media ◽  
Preparation Methods ◽  
Light Spectra

Abstract Three photocatalysts (CdS, ZnFe2O4, and NiFe2O4) were synthesized and their ability to photodegrade methylene blue (MB) was evaluated. MB was degraded by both spinel photocatalysts under visible light at room temperature, although their efficacy was less than that for CdS. The photocatalytic efficacies of NiFe2O4 were observed to be much greater than that for ZnFe2O4. All the synthesized nanoparticles absorbed visible light, while CdS had a larger absorption range within the visible light spectra and the most porous surface. Photo-deactivation was observed during the study, which could be due to the chemical adsorption of the degraded products on the catalyst surface. The factors that affected MB removal efficacy include the absorption range of photocatalysts, initial MB concentrations, amount of photocatalysts added, and photoreactor conditions. Life cycle analysis was used to compare the preparation methods of the photocatalysts in terms of energy consumption and environmental impact. The results showed that the hydrothermal method for NiFe2O4 preparation was less energy-intensive than the sol-gel method for CdS and ZnFe2O4 as the hydrothermal method is effective over a wider range of temperatures in aqueous media. Also, as ZnFe2O4, and NiFe2O4 have lower environmental impacts than CdS both show promise as photocatalysts.

Removal of Cd2+ from Aqueous Solution Using MgAlCO3 -Layered Double Hydroxide

2011 ◽  
Vol 8 (2) ◽  
pp. 13 ◽  
Author(s):  
Nurul Izza Taib ◽  
Norzuyanti Mohd Aris
Keyword(s):  
Contact Time ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Initial Concentration ◽  
Adsorbent Dosage ◽  
Freundlich Isotherms ◽  
Exothermic Process ◽  
Temperature And Pressure ◽  
Co Precipitation ◽  
Double Hydroxide

Anion clay hydrotalcite MgAlCO3 with a Mg/Al molar ratio of 3:1 was synthesized by co-precipitation at room temperature and pressure. The physicochemical properties were evaluated using Powder X-Ray Diffraction (PXRD), Fourier Transform Infrared (FTIR) spectroscopy and Thermogravimetric Analysis (TGA). The efficacy of anion clay hydrotalcite in the removal of Cd2+ from aqueous solutions was investigated with respect to contact time, initial concentration, pH, adsorbent dosage and temperature. The Cd2+ removal increased with the increased in contact time, adsorbent dosage, pH and initial concentration. Adsorption decreases with increasing initial concentration and temperature, for which the latter is indicative of an exothermic process. The equilibrium adsorption capacity of MgAlCO3 was evaluated using linear Langmuir and Freundlich isotherms with respect to the separation factor, RL .

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