PHOTOCATALYTIC DEGRADATION OF AQUEOUS METHYL ORANGE USING NANOTITANIA LOADED Mo-MCM-41

2011 ◽  
Vol 10 (04n05) ◽  
pp. 1131-1135 ◽  
Author(s):  
H. SHANKAR ◽  
R. SARAVANAN ◽  
A. STEPHEN ◽  
V. NARAYANAN
Keyword(s):  
Methyl Orange ◽  
Sol Gel ◽  
Life Time ◽  
Nitrogen Adsorption ◽  
Atomic Ratio ◽  
Silica Matrix ◽  
Uniform Size ◽  
Bet Analysis ◽  
Adsorption Desorption ◽  
Mcm 41

Nanocrystalline titanium dioxide, TiO2 , is a well studied and commonly used material for photocatalytic applications. However, the control of particle size, monodispersity, large catalytic surface for sufficient adsorption of organic pollutants, recovery and recycle of TiO2 nanoparticles are challenging tasks. Hence in this work, titania has been introduced into the nanopores (2–10 nm size) of MCM-41 to produce stable nanoparticles of uniform size and shape. Further, the photocatalytic efficiency can be improved by lengthening the life time of the excited electrons/holes during photoreaction. This could be achieved by incorporating molybdenum in to the MCM-41 silica matrix in addition to titania loading. In the present study, the synthesis and the photocatlaytic efficiency of a new photocatalyst TiO2@Mo -MCM-41 (25 wt.% TiO2 loaded Mo incorporated MCM-41) are reported. Mo -MCM-41, with different ratios of Si to Mo ( Si/Mo = 25,50,75), is synthesized by hydrothermal method and loaded with 25 wt.% TiO2 using sol–gel method. The photocatalytic activity of the prepared samples was evaluated using methyl orange as a model organic compound. X-ray diffraction (XRD), Transmission Electron Microscopy (TEM) and nitrogen adsorption–desorption isotherm (BET analysis) measurements were used to investigate the effects of the incorporated elements in the structure of MCM-41. It was found that the photodegradation ability of 25% TiO2 loaded Mo -MCM-41 was highly related to the amount of Mo atoms present in the sample with the optimum atomic ratio of Si to Mo being 50.

Texture Evaluation of Sol-Gel Derived Mesoporous Bioactive Glass

2013 ◽  
Vol 284-287 ◽  
pp. 230-234
Author(s):  
Yu Jen Chou ◽  
Chi Jen Shih ◽  
Shao Ju Shih
Keyword(s):  
Surface Area ◽  
Calcination Temperature ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Nitrogen Adsorption ◽  
Bioactive Glasses ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Adsorption Desorption

Recent years mesoporous bioactive glasses (MBGs) have become important biomaterials because of their high surface area and the superior bioactivity. Various studies have reported that when MBGs implanted in a human body, hydroxyl apatite layers, constituting the main inorganic components of human bones, will form on the MBG surfaces to increase the bioactivity. Therefore, MBGs have been widely applied in the fields of tissue regeneration and drug delivery. The sol-gel process has replaced the conventional glasses process for MBG synthesis because of the advantages of low contamination, chemical flexibility and lower calcination temperature. In the sol-gel process, several types of surfactants were mixed with MBG precursor solutions to generate micelle structures. Afterwards, these micelles decompose to form porous structures after calcination. Although calcination is significant for contamination, crystalline and surface area in MBG, to the best of the authors’ knowledge, only few systematic studies related to calcination were reported. This study correlated the calcination parameters and the microstructure of MBGs. Microstructure evaluation was characterized by transmission electron microscopy and nitrogen adsorption/desorption. The experimental results show that the surface area and the pore size of MBGs decreased with the increasing of the calcination temperature, and decreased dramatically at 800°C due to the formation of crystalline phases.

scholarly journals Bulk Versus Surface Modification of Alumina with Mn and Ce Based Oxides for CH4 Catalytic Combustion

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1771 ◽  
Author(s):  
Stefan Neatu ◽  
Mihaela M. Trandafir ◽  
Adelina Stănoiu ◽  
Ovidiu G. Florea ◽  
Cristian E. Simion ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Catalytic Combustion ◽  
Mixed Oxides ◽  
Sol Gel ◽  
Nitrogen Adsorption ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Programmed ◽  
Catalytic Combustion Of Methane ◽  
Adsorption Desorption

This study presents the synthesis and characterization of lanthanum-modified alumina supported cerium–manganese mixed oxides, which were prepared by three different methods (coprecipitation, impregnation and citrate-based sol-gel method) followed by calcination at 500 °C. The physicochemical properties of the synthesized materials were investigated by various characterization techniques, namely: nitrogen adsorption-desorption isotherms, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and H2–temperature programmed reduction (TPR). This experimental study demonstrated that the role of the catalytic surface is much more important than the bulk one. Indeed, the incipient impregnation of CeO2–MnOx catalyst, supported on an optimized amount of 4 wt.% La2O3–Al2O3, provided the best results of the catalytic combustion of methane on our catalytic micro-convertors. This is mainly due to: (i) the highest pore size dimensions according to the Brunauer-Emmett-Teller (BET) investigations, (ii) the highest amount of Mn4+ or/and Ce4+ on the surface as revealed by XPS, (iii) the presence of a mixed phase (Ce2MnO6) as shown by X-ray diffraction; and (iv) a higher reducibility of Mn4+ or/and Ce4+ species as displayed by H2–TPR and therefore more reactive oxygen species.

scholarly journals ZnFe2O4-TiO2Nanoparticles within Mesoporous MCM-41

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Aidong Tang ◽  
Yuehua Deng ◽  
Jiao Jin ◽  
Huaming Yang
Keyword(s):  
Sol Gel ◽  
Rutile Phase ◽  
Band Gap Energy ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Agglomeration Of Nanoparticles ◽  
Adsorption Desorption ◽  
Mcm 41

A novel nanocomposite ZnFe2O4-TiO2/MCM-41 (ZTM) was synthesized by a sol-gel method and characterized through X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), N2adsorption-desorption, Raman spectroscopy, and ultraviolet visible (UV-vis) spectrophotometry. The results confirmed the incorporation of ZnFe2O4-TiO2nanoparticles inside the pores of the mesoporous MCM-41 host without destroying its integrity. ZnFe2O4nanoparticles can inhibit the transformation of anatase into rutile phase of TiO2. Incorporation of ZnFe2O4-TiO2within MCM-41 avoided the agglomeration of nanoparticles and reduced the band gap energy of TiO2to enhance its visible light photocatalytic activity. UV-vis absorption edges of ZTM nanocomposites redshifted with the increase of Zn/Ti molar ratio. The nanocomposite approach could be a potential choice for enhancing the photoactivity of TiO2, indicating an interesting application in the photodegradation and photoelectric fields.

Rapid Synthesis of MCM-41 from Rice Husk Using Ultrasonic Wave: Optimation of Sonication Time

2019 ◽  
Vol 948 ◽  
pp. 198-205
Author(s):  
Suyanta Suyanta ◽  
Eko Sri Kunarti ◽  
Bambang Rusdiarso ◽  
Dritta Anies Cahaya ◽  
Efa Radnawati ◽  
...  
Keyword(s):  
Optimum Condition ◽  
Ultrasonic Wave ◽  
Rice Husk ◽  
Nitrogen Adsorption ◽  
Sonication Time ◽  
Ultrasound Waves ◽  
Comb Structure ◽  
Silica Source ◽  
Adsorption Desorption ◽  
Mcm 41

Ultrasound waves with 48 KHz of frequency were applied for the synthesis of MCM-41 using rice husk as the silica source. The effect of sonication time (30, 60, 90, 120, 150, 180, and 210 min) on the crystallinity of calcined MCM-41 was investigated. Characterization using XRD and FTIR indicated that the ordered structure of MCM-41 could be synthesized by ultrasonic wave. Sonication time at 150 min was found to be the optimum condition. The nitrogen adsorption-desorption isotherms informed that the mesoporous material produced at the optimum condition has 794.73 m2·g-1of surface area, 3.02 nm of BJH pore diameter, 1.17 nm of wall thickness, and 0.68 ml·g-1 of pore volume. While based on the TEM image, the material has hexagonal or a honey-comb structure.

Self-Organization in Nanoparticle Titanium Dioxide Thin Films

1998 ◽  
Vol 519 ◽  
Author(s):  
S.D. Burnside ◽  
V. Shklover ◽  
C.A. Barbe ◽  
K. Brooks ◽  
P. Comte ◽  
...  
Keyword(s):  
Thin Films ◽  
Titanium Dioxide ◽  
Sol Gel ◽  
Photovoltaic Performance ◽  
Nitrogen Adsorption ◽  
Self Organization ◽  
X Ray Diffraction ◽  
Nanocrystalline Titanium ◽  
Titanium Dioxide Thin Films ◽  
Adsorption Desorption

AbstractNanocrystalline titanium dioxide has been synthesized using a sol-gel technique followed by hydrothermal growth at temperatures in the range 190-270°C. Thin films of these colloids were studied using x-ray diffraction (XRD), scanning electron microscopy (SEM), and nitrogen adsorption/desorption. Self-organization of the nanocrystalline particles in regular arrays was observed in films made from colloids autoclaved at lower temperatures. We present herein initial photovoltaic performance of these semiconducting films used as working electrodes in a dye-sensitized solar cell.

Catalytic Activity of Argentum-loaded MCM-41 for Ozonation of p- Chlorobenzoic Acid (p-CBA) in Aqueous Solution

2015 ◽  
Vol 18 (1) ◽  
Author(s):  
Zhaoqi Pan ◽  
Junyu Zeng ◽  
Bingyan Lan ◽  
Laisheng Li
Keyword(s):  
Aqueous Solution ◽  
Nitrogen Adsorption ◽  
Hexagonal Structure ◽  
Bet Surface Area ◽  
X Ray Diffraction ◽  
Chlorobenzoic Acid ◽  
Transmission Electron ◽  
Initial Ph ◽  
Adsorption Desorption ◽  
Mcm 41

AbstractArgentum-loaded MCM-41 (Ag/MCM-41) was synthesized successfully by a hydrothermal method and used as a catalyst for the ozonation of p-chlorobenzoic acid (p-CBA) in aqueous solution. Ag/MCM-41 was characterized by low angle X-ray diffraction (XRD), nitrogen adsorption-desorption and transmission electron microscopy (TEM). Characterizations suggest that the prepared samples retained a highly regulated mesopores of hexagonal structure and a high BET surface area. The influences of argentum content, initial pH, reaction temperature on the catalytic ozonation were also evaluated. Ag/MCM-41/O

Synthesis and Characterization of Mesoporous Molecular Sieve Al-MCM-41 Using Kaolin as Raw Material

2013 ◽  
Vol 779-780 ◽  
pp. 201-204
Author(s):  
Miao Li ◽  
Hong Wang ◽  
Xian Qing Li ◽  
Jin Rong Liu
Keyword(s):  
Molecular Sieve ◽  
Nitrogen Adsorption ◽  
Mesoporous Molecular Sieve ◽  
Raw Material ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Adsorption Desorption ◽  
Calcined Kaolin ◽  
Mcm 41

Ordered hexagonally mesoporous molecular sieve Al-MCM-41 with Si/Al (atom) ratio=9 was prepared by hydrothermal synthesis using raw kaolin. X-ray diffraction (XRD), Nitrogen adsorption desorption, Transmission Electron Microscope (TEM) and Energy Dispersive X-ray Detector (EDX) were employed to characterise raw kaolin, calcined kaolin, as-synthesized and calcined Al-MCM-41. The results indicated that characteristic reflections of raw kaolin disappeared after calcination, both of as-synthesized and calcined Al-MCM-41 exhibited well ordered hexagonally mesoporous molecular sieve structure.

Sol-Gel Synthesized Nanostructured Silica Particles for Application in Gas Transport Properties of PU-PDMS Based Mixed-Matrix Membranes

2013 ◽  
Vol 829 ◽  
pp. 862-866
Author(s):  
Mohammad Ali Semsarzadeh ◽  
Eshagh Vakili ◽  
Milad Fardi ◽  
Behnam Ghalei
Keyword(s):  
Electron Microscopy ◽  
Sol Gel ◽  
Nitrogen Adsorption ◽  
Composite Membranes ◽  
Silica Particles ◽  
Gas Permeation ◽  
Mixed Matrix Membranes ◽  
Hybrid Membranes ◽  
Casting Technique ◽  
Bet Analysis

New Silicon based nanostructures particles were successfully synthesized by tetraethoxysilane (TEOS) as silica precursor, mixture of two copolymers of PPG-b-PPE-b-PPG and PEO-b-PPG-b-PEO (Plutonic) as templates. PU-PDMS and PU-PDMS/silica composite membranes were prepared by solution casting technique. Synthesized mesoporus silica particles and hybrid membranes were characterized using Nitrogen adsorption-desorption (BET), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). As confirmed by BET analysis, the mean pore diameters of SPB1,2 Silicon particles are around 9 nm. The SEM micrographs confirmed the nanoscale distribution of silica particles in the polymer matrix. Gas permeation of PU-PDMS/silica hybrid membranes with silica contents of 5, 10 and 20 wt.% was studied for N2, CO2 and He single gases at8 bar. The obtained results suggest a significant increase in permeability of all gases upon increasing the silica particles content. The possible reasons for such behavior were stated and discussed.

Synthesis、Structure and Catalytic Activity of TiO2/ La2Zr2O7 Nanocomposites

2011 ◽  
Vol 239-242 ◽  
pp. 2878-2881
Author(s):  
Yu Ping Tong ◽  
Yu Qing Zhao ◽  
Hong Yuan Huo ◽  
Hui Yang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Photocatalytic Activity ◽  
Methyl Orange ◽  
Sol Gel ◽  
Photocatalytic Property ◽  
Nitrogen Adsorption ◽  
Bet Surface Area ◽  
X Ray ◽  
Scanning Electron

TiO2/La2Zr2O7 composites were fabricated by sol-gel method. The composites were characterized by X-ray powder diffraction (XRD), Raman spectrum, scanning electron microscopy (SEM), energy dispersive X-ray spectrometer (EDS) and Brunauer-Emmett-Teller (BET) nitrogen adsorption. The results showed that TiO2 was uniformly coated on the surface of La2Zr2O7 powders. The BET surface area of TiO2/La2Zr2O7 composites was 26.78 m2/g, which was larger than that of La2Zr2O7. Also, the photodegradation of methyl orange was used to evaluate its photocatalytic property. It was found that TiO2/La2Zr2O7 composites showed good photocatalytic activity and the decomposition of methyl orange had basically completed within 30 min.

scholarly journals Enhanced Photocatalytic Removal of Cyanotoxins by Al-Doped ZnO Nanoparticles with Visible-LED Irradiation

Toxins ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 66
Author(s):  
Majdi Benamara ◽  
Elvira Gómez ◽  
Ramzi Dhahri ◽  
Albert Serrà
Keyword(s):  
Photocatalytic Degradation ◽  
Diffuse Reflectance Spectroscopy ◽  
Degradation Kinetics ◽  
Sol Gel ◽  
Nitrogen Adsorption ◽  
Zno Nanoparticle ◽  
Al Content ◽  
Doped Zno ◽  
Adsorption Desorption ◽  
Neutral Conditions

The ZnO-based visible-LED photocatalytic degradation and mineralization of two typical cyanotoxins, microcystin-LR (MC-LR), and anatoxin-A were examined. Al-doped ZnO nanoparticle photocatalysts, in Al:Zn ratios between 0 and 5 at.%, were prepared via sol-gel method and exhaustively characterized by X-ray diffraction, transmission electron microscopy, UV-vis diffuse reflectance spectroscopy, photoluminescence spectroscopy, and nitrogen adsorption-desorption isotherms. With both cyanotoxins, increasing the Al content enhances the degradation kinetics, hence the use of nanoparticles with 5 at.% Al content (A5ZO). The dosage affected both cyanotoxins similarly, and the photocatalytic degradation kinetics improved with photocatalyst concentrations between 0.5 and 1.0 g L−1. Nevertheless, the pH study revealed that the chemical state of a species decisively facilitates the mutual interaction of cyanotoxin and photocatalysts. A5ZO nanoparticles achieved better outcomes than other photocatalysts to date, and after 180 min, the mineralization of anatoxin-A was virtually complete in weak alkaline medium, whereas only 45% of MC-LR was in neutral conditions. Moreover, photocatalyst reusability is clear for anatoxin-A, but it is adversely affected for MC-LR.

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