Preparation of Titanium Hexacyanoferrate Microspheres (Diameter <70 μm) by Water Extraction Variant of Sol-Gel Process and its Application to Sorption of 137Cs from Nuclear Reactor Cooling Water

1995 ◽  
Vol 412 ◽  
Author(s):  
A. Deptula ◽  
A. G. Chmielewski ◽  
W. Lada ◽  
T. Olczak
Keyword(s):  
Aqueous Solution ◽  
Nuclear Reactor ◽  
Sol Gel ◽  
Cooling Water ◽  
Special Procedure ◽  
Sol Gel Process ◽  
High Sorption ◽  
Emulsion Drops ◽  
Titania Sol ◽  
Dta Studies

AbstractTitanium hexacyanoferrate microspheres (diameter <70km) were obtained in the following steps: (1) extraction of chlorides from an aqueous solution of TiCl4 with long chain amine -Primene JMT- in paraffin diluent (the resulting sol has the concentration 320 g TiO2/dm3 and the mole ratio Cl-: Ti4+ = 1.83); (2) blending of titania sol with an aqueous solution of K4 Fe(CN)6. 3H2O (280 g/dm3) in order to obtain final sols with Fe(CN)64-: Ti4+ mole ratio of 0.05 - 0.1; (3) formation of multicomponent sol emulsion in 2-ethylhexanol-1 containing I vol. % of Ethomen S/15 (EH), (4) gelation of emulsion drops by extraction of water with partially dehydrated EH; (5) filtration and washing with acetone; (6) drying at 140°C using a special procedure elaborated on the basis of TG and DTA studies.The final product is insoluble in water and exhibits high sorption efficiency of 137 Cs.

Some Comments on the Production of Medium Sized Spherical Particles by Anion and Water Extraction Variant of Sol-Gel Process

1994 ◽  
Vol 372 ◽  
Author(s):  
A. Deptula ◽  
W. Łstoke;ada ◽  
T. Olczak ◽  
A. Chmielewski
Keyword(s):  
Particle Size ◽  
Sol Gel ◽  
Ceramic Materials ◽  
Extraction Process ◽  
Spherical Particles ◽  
Drastic Reduction ◽  
Sol Gel Process ◽  
Emulsion Drops ◽  
Clustering Effect ◽  
Non Destructive

AbstractMedium sized spherical particles (with diameters below 100 μm) of ceramic materials (Al203 and Al203 +8%TiO2) were produced in the following steps: (1) preparation of concentrated hydroxide sols of cations by extraction of anions using Primene JMT, (2) formation of sol emulsion in 2-ethylhexanol-1 containing various amounts of surfactants (EH), (3) gelation of emulsion drops by extraction of water with partially dehydrated EH, (4) non-destructive thermal treatment. Principal properties of the sol depend on the temperature of the extraction process. For preparation of lowanionic sols a two step extraction process, separated by digestion of the aqueous phase at boiling point, was necessary. It was found that the parameters of emulsion formation as well as the properties of the sols significantly influence the particle size distribution. It was concluded that lowering of the sol- EH interracial tension by the surfactant does not influence the process. On the contrary the “anti-clustering” effect of surfactants is essential for preparation of perfect spherical powders. The thermal decomposition of gels to oxides is determinant for densities, specific surface area and carbon content. Medium sized spherical powders are free flowing. The compactibility and sinterability of those powders are poor. However drastic reduction of particle size by milling (connected with their transformation to irregular shape) significantly improves the sinterability.

Preparation of BSCCO Precursors by Water Extraction Variant of Sol-Gel Process

1992 ◽  
Vol 271 ◽  
Author(s):  
A. Deptula ◽  
W. Lada ◽  
T. Olczak ◽  
A. Di Bartolomeo
Keyword(s):  
Thermal Treatment ◽  
Sol Gel ◽  
Water Extraction ◽  
Sol Gel Process ◽  
Emulsion Drops ◽  
Preparation Step

ABSTRACTThe starling acetate sols of molar compositions of Bi:Pb:Sr:Ca:Cu=I-2:O:2:l: 2, 11–2:0:2:2:3 and 111–1.6:0.4:2:2:3 were prepared by NH4OH addition at various rates, followed by evaporation. Sols were gelled by further evaporation to shard or to microspheres (diameter below 100 μm) by water extraction from the sol emulsion drops formed in 2-ethyl-l-hexanol. The gels were converted to BSCCO phases by thermal treatment. The processes were characterized by XRD and IR examinations. The influence of the sol preparation step connected with formation of polynuclear cations on the following stages of the process was examined.

Photooxidation Activity of Mixed Phase TiO2 Nanoparticles

2014 ◽  
Vol 998-999 ◽  
pp. 79-82
Author(s):  
Jing Wei ◽  
Liang Guo Yan ◽  
Hang Li ◽  
Yi Yi Zhao
Keyword(s):  
Aqueous Solution ◽  
Crystal Structures ◽  
Rhodamine B ◽  
Degradation Rate ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mixing Ratios ◽  
Calcination Temperatures ◽  
Sol Gel Process

The different mixing ratios of TiO2 nanoparticles were synthesized using sol–gel process by changing the temperature of calcinations. The crystal structures were characterized by X-ray diffraction (XRD). The photocatalytic action of TiO2 nanoparticles was investigated through the photooxidation of Rhodamine B in aqueous solution. The XRD results indicated that the rutile ratios of different calcination temperatures (500°C, 600°C, 700°C and 800°C, respectively) TiO2 nanoparticles were 0%, 20.87%, 92.41% and 100%, respectively. The TiO2 nanoparticles which calcinated at 600 °C had the highest photocatalytic action; under UV irradiation of 4 h, initial Rhodamine B concentration of 15 mg/L, TiO2 nanoparticles (calcinated at 600 °C) dosage of 1g/L, the degradation rate of Rhodamine B could achieve to 97.87%. The addition of rutile to anatase could particularly improve the photooxidation activity of TiO2 nanoparticles.

Sol-Gel Processing and Novel Physical Properties of PLZT 7/57/43 Ferroelectric Ceramics

2013 ◽  
Vol 873 ◽  
pp. 292-297 ◽  
Author(s):  
Ke Yu Zheng ◽  
Ya Li Ding ◽  
Ren Zhi Shao
Keyword(s):  
Physical Properties ◽  
Piezoelectric Properties ◽  
Perovskite Phase ◽  
Ferroelectric Properties ◽  
Sol Gel ◽  
Ferroelectric Ceramics ◽  
Nominal Composition ◽  
Electrical Measurements ◽  
Sol Gel Process ◽  
Dta Studies

The sol-gel process was employed to prepare (Pb1-xLax)(Zr1-yTiy)O3(PLZT) ceramics with nominal composition Pb0.93La0.07(Zr0.57Ti0.43)0.9825O3. The structure and physical properties such as dielectric, piezoelectric and ferroelectric properties were investigated. X-ray diffraction results showed that the perovskite phase PLZT was formed when the sol-gel processed powders was calcined at 600°Cfor 4 hours. nanocrystalline particles with a size of ~50nm were found. TG-DTA studies were used to analyze the thermal properties of nanopowders for understanding the reaction kinetics in them. Wafered bulk ceramic samples prepared from the sol-gel derived powders were subjected to electrical measurements, in order to determine the dielectric, piezoelectric and ferroelectric properties. The dielectric properties of the PLZTBST system are further improved and the dielectric piezoelectric properties of PLZT ceramics are found to be sensitive to the particle size of PLZT nanopowders. The dielectric piezoelectric properties of polarized PLZT ceramics can be improved with the lessening of PLZT nanopowder size. Meanwhile, the grain size of PLZT ceramics decreases.

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