scholarly journals Urea-Assisted Synthesis of Mesoporous TiO2 Photocatalysts for the Efficient Removal of Clofibric Acid from Water

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6035
Author(s):  
Lidia Favier ◽  
Amalia Maria Sescu ◽  
Elaziouti Abdelkader ◽  
Laurence Oughebbi Berthou ◽  
Doina Lutic
Keyword(s):  
Sol Gel ◽  
Mesoporous Tio2 ◽  
Clofibric Acid ◽  
Water Remediation ◽  
Ammonium Bromide ◽  
Tio2 Photocatalysts ◽  
Different Temperatures ◽  
Cetyl Trimethyl Ammonium ◽  
Catalyst Reusability ◽  
High Yields

Mesoporous TiO2 photocatalysts intended for the advanced removal of clofibric acid (CA) from water were synthesized by the sol-gel method in a medium containing cetyl-trimethyl-ammonium bromide (CTAB) and urea, using either ethanol or isopropanol to dilute the TiO2 precursor. The activation of the samples was undertaken at 550, 650 and 750 °C. The XRD revealed that the nature of the solvent resulted in significant differences in the anatase-to-rutile ratios obtained at different temperatures. The specific surface area values were situated between 9 and 43 m2g−1 and the band gap values were similar for all the samples. The photocatalytic activity of the prepared samples was examined for the degradation of CA, an emergent water contaminant. The photocatalytic tests performed under UV-A irradiation revealed that the photo-reactivity of these materials depends on the calcination temperature. The best results were obtained for the samples calcined at 750 °C, which showed high yields of CA elimination, as well as almost complete mineralization (over 95%) after 180 min of reaction. Good results in terms of catalyst reusability in the reaction were found for the catalyst showing the highest photo-reactivity. Therefore, the samples can be considered good candidates for future water remediation applications.

Impedance Analysis and Modulus Spectroscopy of Fe (III) Containing Strontium Stannate Nanoparticles

2016 ◽  
Vol 860 ◽  
pp. 3-6 ◽  
Author(s):  
Ashok Kumar ◽  
Astakala Anil Kumar ◽  
Jitender Kumar Quamara
Keyword(s):  
Sol Gel ◽  
Orthorhombic Phase ◽  
Impedance Analysis ◽  
Ammonium Bromide ◽  
Fe Content ◽  
Modulus Spectroscopy ◽  
Strontium Stannate ◽  
Different Temperatures ◽  
Cetyl Trimethyl Ammonium ◽  
Sol Gel Synthesis

We report the sol-gel synthesis of pristine and Fe containing perovskite structured strontium stannate nanoparticles, stabilized by cetyl trimethyl ammonium bromide (CTAB). The X-ray diffraction data of pristine and Fe doped strontium stannate nanoparticles reveals the formation of orthorhombic phase with Pbnm space symmetry. Raman spectra of pristine and Fe doped SrSnO3 nanoparticles depicts peaks at 220, 256 and 561 corresponding to Sn-O-Sn, O-Sn-O and Sn-O band stretching, respectively. The dc resistivity of pristine and Fe doped SrSnO3 is found to decrease with increase in Fe content. The variation of impedance (Zʹ and Z′′) and electric modulus (Mʹ and M′′) of pristine and Fe doped strontium stannate nanoparticles as a function of frequency (20 Hz to 2 MHz) at different temperatures (310-410 K) has been studied.

Mobility of DR1 Molecules Embedded in Nanostructured PMMA Films

2009 ◽  
Vol 5 ◽  
pp. 135-142
Author(s):  
Jorge A. García-Macedo ◽  
A. Franco ◽  
Guadalupe Valverde-Aguilar ◽  
M.A. Ríos-Enríquez
Keyword(s):  
Second Harmonic ◽  
Sodium Dodecyl ◽  
Orientation Distribution ◽  
Decay Rates ◽  
Ammonium Bromide ◽  
X Ray Diffraction ◽  
Poling Field ◽  
Different Temperatures ◽  
Cetyl Trimethyl Ammonium ◽  
Kinetics Of

The kinetics of the orientation of Disperse Red 1 (DR1) molecules embedded in nanostructured Polymethylmetacrylate (PMMA) films was studied under the effect of an intense constant electric poling field. The changes in the orientation distribution of the DR1 molecules were followed by Second Harmonic Generation (SHG) measurements. The SHG signal was recorded as function of time at three different temperatures. We focused on both, the signal increases under the presence of the poling field and the signal decays without the poling field. The studied PMMA films were nanostructured by the incorporation of ionic surfactants as the Sodium Dodecyl Sulfate (SDS) and the Cetyl Trimethyl Ammonium Bromide (CTAB) during their preparation. The kinds of nanostructures obtained in the films were determined by means of X-ray diffraction (XRD) measurements. Substantial differences in signal intensity and in growth and decay rates between amorphous and nanostructured films were found.

Experimental and Theoretical Studies of Thermophysical Properties of MgO-Water Nanofluid

2020 ◽  
Vol 1008 ◽  
pp. 47-52
Author(s):  
Abdallah Yousef Mohammed Ali ◽  
Ahmed Hassan El-Shazly ◽  
Marwa Farouk El-Kady ◽  
Hesham Ibrahim Elqady ◽  
Kholoud Madih ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermophysical Properties ◽  
Volume Fraction ◽  
Sol Gel ◽  
Solid Volume Fraction ◽  
Ammonium Bromide ◽  
Distilled Water ◽  
Step Method ◽  
Mgo Nanoparticles ◽  
Cetyl Trimethyl Ammonium

Magnesium oxide (MgO) nanoparticles were synthesized using the sol-gel technique then characterized. Cetyl Trimethyl Ammonium Bromide (CTAB) surfactant was added to reduce Van der Waal forces among MgO nanoparticles and distilled water forming a stable nanofluid using two-step method with aid of ultrasound sonication. Pure distilled water and nanofluids with different volume fractions of 0.25, 0.5, 0.75, and 1% are used as working fluids. Thermophysical properties of prepared nanofluids were measured experimentally and determined theoretically. Effect of solid volume fraction on the thermophysical properties; including thermal conductivity, heat capacity, viscosity, and density of MgO-water nanofluids are discussed. Moreover, experimental results have been compared with the suitable correlations for MgO-water nanofluid. The findings show that thermal conductivity, viscosity, and density of nanofluid increases with increasing solid volume fraction.

scholarly journals Preparation and photocatalytic activity analysis of nanometer TiO2 modified by surfactant

2018 ◽  
Vol 8 ◽  
pp. 184798041878197 ◽  
Author(s):  
Wenzheng Wu ◽  
Longjian Zhang ◽  
Xiaojie Zhai ◽  
Ce Liang ◽  
Kaifeng Yu
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Anatase Phase ◽  
Sol Gel ◽  
Sodium Dodecyl ◽  
Sodium Dodecyl Benzene Sulfonate ◽  
Ammonium Bromide ◽  
Transmission Electron ◽  
Cetyl Trimethyl Ammonium ◽  
Nano Titanium Dioxide

Combining the advantages of the sol–gel method and solvothermal method, the single anatase phase of nano-titanium dioxide (TiO2) with high crystallinity had been prepared by means of the sol–solvent thermal improved process, in which butyl titanate was used as titanium source; anhydrous ethanol as solvent; concentrated nitric acid as inhibitor; and cationic surfactant cetyl trimethyl ammonium bromide (CTAB), anionic surfactant sodium dodecyl benzene sulfonate (SDBS), and nonionic surfactant polyethylene glycol (PEG) as dispersants. The analysis results of Brunauer–Emmett–Teller, scanning electron microscopy, and transmission electron microscopy characterizations indicated that CTAB-modified TiO2 with the optimum ratio had the most apparent dispersibility and the highest specific surface area compared with unmodified TiO2, SDBS-modified TiO2, and PEG-modified TiO2. At the same time, the photocatalytic degradation rate of methyl orange could be improved to 99.16%. It indicated that the modification effect of CTAB was significantly better than those of SDBS and PEG, which made the nanoparticles uniformly dispersed, resulting in higher photocatalytic activity.

Preparation and Characterization of Nano-Porous SiO2/TiO2-SiO2 Thin Films on Glass Substrates by Sol-Gel Method

2012 ◽  
Vol 531-532 ◽  
pp. 651-654
Author(s):  
Qing Nan Zhao ◽  
Ying Liu ◽  
Shao Hong Hou ◽  
Wu Zeng ◽  
Jie Sun
Keyword(s):  
Surface Morphology ◽  
Raw Materials ◽  
Sol Gel ◽  
Amorphous Structure ◽  
Tetrabutyl Titanate ◽  
Ammonium Bromide ◽  
Gel Method ◽  
Sol Gel Method ◽  
Glass Substrates ◽  
Cetyl Trimethyl Ammonium

Nano-porous bilayers structure antireflection films on glass substrate were prepared by sol-gel method, tetraethyl orthosilicate(TEOS) and tetrabutyl titanate(TEOT) as the main raw materials, cetyl trimethyl ammonium bromide(CTAB) and polyethylene glycol(PEG) as template. The relation of the template agent addition, pH, and aging time to surface morphology and optical properties were analyzed. When the CTAB/TEOS = 1/30, the average spectral transmittance in the visible wavelength is 93.69% and the peak transmission is up to 97.37%. All the bilayers antireflection films are amorphous structure, uniform surface morphology, dense nano-porous size distribution, pore size is about 10nm.

scholarly journals Preparation of mesoporous ammonium phosphotungstate/silica catalyst and study on the degradation performance of chlorothalonil

2020 ◽  
Author(s):  
Wei Tan ◽  
Yifei Zhang ◽  
Tianli Wang ◽  
Lei Liu ◽  
Junxiu Ye ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Raw Materials ◽  
Aquatic Toxicity ◽  
Sol Gel ◽  
Water System ◽  
Ammonium Bromide ◽  
Alcohol Water ◽  
Ft Ir ◽  
Cetyl Trimethyl Ammonium ◽  
Degradation Effect

Abstract Chlorothalonil is widely used to control fungal diseases and it is usually detected in the environment. Phototransformation is an important process to remove chlorothalonil from the aquatic environment. The mesoporous ammonium phosphotungstate/silica catalyst (NH4PW/SiO2) was synthesized from cetyl trimethyl ammonium bromide (CTAB) and tetraethoxysilane (TEOS) as raw materials by adding insoluble ammonium phosphotungstate into the alkaline alcohol–water system by the sol-gel method. The structure of NH4PW/SiO2 was characterized by X-ray diffractometry (XRD), Brunauer–Emmett–Teller (BET) and Fourier transform infrared spectroscopy (FT-IR). The photocatalytic activity of NH4PW/SiO2 was evaluated by using the organic pesticide chlorothalonil as a model reactant. The result indicated that when the dosage of NH4PW/SiO2 is 0.02 g, the illumination is 180 min, the concentration of chlorothalonil is 5 mg/L, pH = 5, the degradation effect is better, and the degradation rate reaches 83.23%. The results contributed to the understanding of chlorothalonil phototransformation and the potential of mesoporous SiO2 to effectively enhance the photocatalytic activity of NH4PW (64.16%) to reduce aquatic toxicity and pollution by chlorothalonil.

Gum arabic helps prepare better lacey polymer films for specimen support in electron microscopy

1993 ◽  
Vol 51 ◽  
pp. 240-241
Author(s):  
Shailesh R. Sheth ◽  
Jayesh R. Bellare
Keyword(s):  
Electron Microscopy ◽  
Polymer Films ◽  
Gum Arabic ◽  
Complete Removal ◽  
Ammonium Bromide ◽  
Release Agent ◽  
Astigmatism Correction ◽  
Long Time ◽  
Micro Holes ◽  
Cetyl Trimethyl Ammonium

Specimen support and astigmatism correction in Electron Microscopy are at least two areas in which lacey polymer films find extensive applications. Although their preparation has been studied for a very long time, present techniques still suffer from incomplete release of the film from its substrate and presence of a large number of pseudo holes in the film. Our method ensures complete removal of the entire lacey film from the substrate and fewer pseudo holes by pre-treating the substrate with Gum Arabic, which acts as a film release agent.The method is based on the classical condensation technique for preparing lacey films which is essentially deposition of minute water or ice droplets on the substrate and laying the polymer film over it, so that micro holes are formed corresponding to the droplets. A microscope glass slide (the substrate) is immersed in 2.0% (w/v) aq. CTAB (cetyl trimethyl ammonium bromide)-0.22% (w/v) aq.

Development of High Permeability Core Materials for Embeddable Inductors in Flexible Organic Substrates

2003 ◽  
Vol 769 ◽  
Author(s):  
C. K. Liu ◽  
P. L. Cheng ◽  
S. Y. Y. Leung ◽  
T. W. Law ◽  
D. C. C. Lam
Keyword(s):  
Low Temperature ◽  
Sol Gel ◽  
Circuit Board ◽  
Organic Substrates ◽  
Circuit Boards ◽  
High Permeability ◽  
Electrical Measurements ◽  
Different Temperatures ◽  
Spiral Inductors ◽  
Ceramic Tape

AbstractCapacitors, resistors and inductors are surface mounted components on circuit boards, which occupy up to 70% of the circuit board area. For selected applications, these passives are packaged inside green ceramic tape substrates and sintered at temperatures over 700°C in a co-fired process. These high temperature processes are incompatible with organic substrates, and low temperature processes are needed if passives are to be embedded into organic substrates. A new high permeability dual-phase Nickel Zinc Ferrite (DP NZF) core fabricated using a low temperature sol-gel route was developed for use in embedded inductors in organic substrates. Crystalline NZF powder was added to the sol-gel precursor of NZF. The solution was deposited onto the substrates as thin films and heat-treated at different temperatures. The changes in the microstructures were characterized using XRD and SEM. Results showed that addition of NZF powder induced low temperature transformation of the sol-gel NZF phase to high permeability phase at 250°C, which is approximately 350°C lower than transformation temperature for pure NZF sol gel films. Electrical measurements of DP NZF cored two-layered spiral inductors indicated that the inductance increased by three times compared to inductors without the DP NZF cores. From microstructural observations, the increase is correlated with the changes in microstructural connectivity of the powder phase.

Reactivity of Barbituric, Thiobarbituric Acids and Their Related Analogues: Synthesis of Substituted and Heterocycles-based Pyrimidines

2020 ◽  
Vol 24 (14) ◽  
pp. 1610-1642 ◽  
Author(s):  
Ahmed El-Mekabaty ◽  
Hassan A. Etman ◽  
Ahmed Mosbah ◽  
Ahmed A. Fadda
Keyword(s):  
Xanthine Oxidase ◽  
Multicomponent Reactions ◽  
Biological Activities ◽  
Present Review ◽  
Urease Inhibitors ◽  
Effective Catalyst ◽  
Inhibitory Activities ◽  
Catalyst Reusability ◽  
High Yields ◽  
Nano Catalysts

Barbituric, thiobarbituric acids and their related analogs are reactive synthons for the synthesis of drugs and biologically, and pharmaceutically active pyrimidines. The present review aimed to summarize the recent advances in the synthesis of different alkylsubstituted, fused cycles, spiro-, and binary heterocycles incorporated pyrimidine skeleton based on barbituric derivatives. In this sequence, the eco-friendly techniques under catalytic conditions were used for the diverse types of multicomponent reactions under different conditions for the synthesis of various types of heterocycles. Nano-catalysts are efficient for the synthesis of these compounds in high yields and effective catalyst reusability. The compounds are potent antibacterial, cytotoxic, xanthine oxidase inhibitory activities, and attend as urease inhibitors. The projected mechanisms for the synthesis of pyranopyrimidines, benzochromenopyrimidines, chromeno-pyranopyrimidines, spiroxyindoles, oxospiro-tricyclic furopyrimidines, pyrimidine-based monoand bicyclic pyridines were discussed. The potent and diverse biological activities for instance, antioxidant, antibacterial, cytotoxic, and xanthine oxidase inhibitory activities, as well as urease inhibitors, are specified.

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