Interaction of hafnium tetrafluoride with ammonium fluoride in aqueous solution

1965 ◽  
Vol 14 (7) ◽  
pp. 1097-1100
Author(s):  
N. P. Sazhin ◽  
B. V. Shchepochkin ◽  
G. A. Yagodin
Keyword(s):  
Aqueous Solution ◽  
Ammonium Fluoride ◽  
Hafnium Tetrafluoride

Photodegradation of Phenol Using TiO2 Nanotubular Thin Film Fabricated by Sonoelectrochemical Anodization

2015 ◽  
Vol 799-800 ◽  
pp. 27-31
Author(s):  
Mohd Hasmizam Razali ◽  
Ahmad Fauzi Mohd Noor ◽  
Mahani Yusoff
Keyword(s):  
Thin Film ◽  
Aqueous Solution ◽  
Chemical Element ◽  
Uv Light ◽  
Phenol Degradation ◽  
Ammonium Fluoride ◽  
High Photocatalytic Activity ◽  
Applied Potential ◽  
Anodization Process ◽  
Sem Analyses

Photodegradation of phenol in aqueous solution was carried out using TiO2 nanotubular thin film. The TiO2 nanotubular thin film has been fabricated by sonoelectrochemical anodization process using a mixture of ethylene glycol and ammonium fluoride as electrolyte. The process was carried out at constant applied potential (20 V) for 90 minutes. After anodization the TiO2 nanotubular film was annealed at 500 °C for 2 hours and characterized using SEM and EDX to study morphology and chemical element compositions. SEM analyses revealed that the fabricated thin film had tubular structure with the diameter between 45 – 64 nm and 6.8 um in length composed of titanium and oxygen elements were determined by EDX. The fabricated TiO2 nanotubular thin film showed high photocatalytic activity with 80.70 % phenol degradation after 5 hours irradiation with UV light.

Modeling Phase Behavior of Semi-Clathrate Hydrates of CO2, CH4, and N2 in Aqueous Solution of Tetra-n-butyl Ammonium Fluoride

2019 ◽  
Vol 44 (2) ◽  
pp. 155-167 ◽  
Author(s):  
Mohammad Mesbah ◽  
Sanaz Abouali Galledari ◽  
Ebrahim Soroush ◽  
Masumeh Momeni
Keyword(s):  
Aqueous Solution ◽  
Ammonium Fluoride ◽  
Simplex Algorithm ◽  
Clathrate Hydrates ◽  
Guest Molecules ◽  
Tuning Parameters ◽  
Clathrate Compounds ◽  
System Temperature ◽  
Robinson Equation ◽  
Good Agreement

AbstractSemi-clathrate hydrates are members of the class of clathrate compounds. In comparison with clathrate hydrates, where the networks are formed only by H2O molecules, the networks of semi-clathrate hydrates are formed by mixtures of H2O and quaternary ammonium salts (QASs). The addition of QASs to the solution enables to improve the formation of semi-clathrate hydrates at much milder conditions comparing to clathrate hydrates. In this work, we study the phase equilibria of semi-clathrate hydrates of CH4, CO2, and N2gas in an aqueous solution of tetra-n-butyl ammonium fluoride (TBAF). An extension of the Chen–Guo model is proposed as a thermodynamic model. The Peng–Robinson equation of state (PREOS) was applied to calculate the fugacity of the gas phase and in order to determine the water activity in the presence of TBAF, a correlation between the system temperature, the TBAF mass fraction, and the nature of the guest molecules has been used. These equations were solved simultaneously and through optimizing tuning parameters via the Nelder–Mead simplex algorithm. The results are compared to experimental data and good agreement is observed.

Anodization of Zirconia Nanotubes for Lead (II) Adsorption

2018 ◽  
Vol 939 ◽  
pp. 113-119
Author(s):  
Mary Donnabelle L. Balela ◽  
Clarisse Mancera ◽  
Bianca Patricia Reyes ◽  
Ma. Christine Reyes
Keyword(s):  
Heavy Metals ◽  
Aqueous Solution ◽  
Oxide Layer ◽  
Pore Diameter ◽  
Ammonium Fluoride ◽  
Nanotube Array ◽  
Adsorption Time ◽  
Initial Concentration ◽  
Zro2 Nanotubes

Zirconia (ZrO2) nanotubes were prepared by anodization of zirconium (Zr) foil in a glycerol-formamide electrolyte containing ammonium fluoride. The effects of anodizing voltage and temperature on the pore diameter and thickness of the resulting nanotube array were studied. ZrO2 nanotubes with larger pore diameter were formed at higher anodizing voltage and temperature. Additinally, the thickness of the oxide layer was also increased. The applicability of the ZrO2 nanotubes for adsorption of heavy metals in aqueous solution was evaluated using Pb (II) as the model ions. Generally, the uptake of Pb (II) was increased at longer adsorption time and higher initial concentration of the adsorbate.

Structures Formed by Cryoprotective Agents Used in Freezc-Etching

1971 ◽  
Vol 29 ◽  
pp. 448-449
Author(s):  
G. G. Cocks ◽  
C. E. Cluthe
Keyword(s):  
Aqueous Solution ◽  
Polyethylene Oxide ◽  
Liquid Nitrogen Temperature ◽  
Ice Crystals ◽  
Etching Technique ◽  
Structural Constituent ◽  
Cryoprotective Agents ◽  
Quick Freezing ◽  
Freeze Etching ◽  
Fractured Surface

The freeze etching technique is potentially useful for examining dilute solutions or suspensions of macromolecular materials. Quick freezing of aqueous solutions in Freon or propane at or near liquid nitrogen temperature produces relatively large ice crystals and these crystals may damage the structures to be examined. Cryoprotective agents may reduce damage to the specimem, hut their use often results in the formation of a different set of specimem artifacts.In a study of the structure of polyethylene oxide gels glycerol and sucrose were used as cryoprotective agents. The experiments reported here show some of the structures which can appear when these cryoprotective agents are used.Figure 1 shows a fractured surface of a frozen 25% aqueous solution of sucrose. The branches of dendritic ice crystals surrounded hy ice-sucrose eutectic can be seen. When this fractured surface is etched the ice in the dendrites sublimes giving the type of structure shown in Figure 2. The ice-sucrose eutectic etches much more slowly. It is the smooth continuous structural constituent surrounding the branches of the dendrites.

Preparation and characterisation of vanadium pentoxide supported rhodium catalyst

1988 ◽  
Vol 46 ◽  
pp. 946-947
Author(s):  
A. Legrouri
Keyword(s):  
Aqueous Solution ◽  
Thermal Decomposition ◽  
Physicochemical Properties ◽  
Surface Area ◽  
Vanadium Pentoxide ◽  
High Purity ◽  
Gas Adsorption ◽  
Rhodium Catalyst ◽  
Optical Methods ◽  
Reducible Oxides

The industrial importance of metal catalysts supported on reducible oxides has stimulated considerable interest during the last few years. This presentation reports on the study of the physicochemical properties of metallic rhodium supported on vanadium pentoxide (Rh/V2O5). Electron optical methods, in conjunction with other techniques, were used to characterise the catalyst before its use in the hydrogenolysis of butane; a reaction for which Rh metal is known to be among the most active catalysts.V2O5 powder was prepared by thermal decomposition of high purity ammonium metavanadate in air at 400 °C for 2 hours. Previous studies of the microstructure of this compound, by HREM, SEM and gas adsorption, showed it to be non— porous with a very low surface area of 6m2/g3. The metal loading of the catalyst used was lwt%Rh on V2Q5. It was prepared by wet impregnating the support with an aqueous solution of RhCI3.3H2O.

TEM observation of iron oxide pillars in montmorillonite

1990 ◽  
Vol 48 (4) ◽  
pp. 882-883
Author(s):  
H. Mori ◽  
Y. Murata ◽  
H. Yoneyama ◽  
H. Fujita
Keyword(s):  
Aqueous Solution ◽  
Iron Oxide ◽  
Fine Particles ◽  
Aqueous Suspension ◽  
Volume Ratio ◽  
Exchange Capacity ◽  
Nano Composites ◽  
Pillared Montmorillonite ◽  
Topographic Features ◽  
Transmission Electron

Recently, a new sort of nano-composites has been prepared by incorporating such fine particles as metal oxide microcrystallites and organic polymers into the interlayer space of montmorillonite. Owing to their extremely large specific surface area, the nano-composites are finding wide application[1∼3]. However, the topographic features of the microstructures have not been elucidated as yet In the present work, the microstructures of iron oxide-pillared montmorillonite have been investigated by high-resolution transmission electron microscopy.Iron oxide-pillared montmorillonite was prepared through the procedure essentially the same as that reported by Yamanaka et al. Firstly, 0.125 M aqueous solution of trinuclear acetato-hydroxo iron(III) nitrate, [Fe3(OCOCH3)7 OH.2H2O]NO3, was prepared and then the solution was mixed with an aqueous suspension of 1 wt% clay by continuously stirring at 308 K. The final volume ratio of the latter aqueous solution to the former was 0.4. The clay used was sodium montmorillonite (Kunimine Industrial Co.), having a cation exchange capacity of 100 mequiv/100g. The montmorillonite in the mixed suspension was then centrifuged, followed by washing with deionized water. The washed samples were spread on glass plates, air dried, and then annealed at 673 K for 72 ks in air. The resultant film products were approximately 20 μm in thickness and brown in color.

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