Saga Ceramics Research Laboratory

Saga-shi, Japan

Saga Ceramics Research Laboratory

Saga-shi, Japan
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Seliem M.K.,Pennsylvania State University | Seliem M.K.,Beni Suef University | Komarneni S.,Pennsylvania State University | Parette R.,Matson and Associates Inc. | And 5 more authors.
Applied Clay Science | Year: 2011

A variety of oraganosilicas such as MCM-41 and MCM-48 and composites of rice husks with MCM-48 were synthesized under an array of conditions and characterized by powder X-ray diffraction (XRD). Various MCM-41 mesoporous materials were prepared at room temperature using different surfactants. MCM-48 silica and its composites with rice husks were synthesized under hydrothermal conditions using cetyltrimethylammonium (CTMA) bromide and rice husks. Both untreated and carbonized rice husks were used for preparing composites of rice husk with MCM-48. Organo-clay minerals procured from two commercial sources were also investigated for their perchlorate uptake. Among the MCM-41 materials, the sample prepared from octadecyltrimethylammonium (ODTMA) chloride showed the highest perchlorate uptake capacity of 0.227 ± 0.006. meq/g while MCM-48 showed the highest perchlorate uptake capacity of 0.437 ± 0.011. meq/g among all the oraganosilicas and organo-clay minerals tested here. The uptake of perchlorate by organosilicas and organo-clay minerals is due to residual positive charge on the surfactants located in the mesopores of organosilicas and interlayers of organo-clay minerals. © 2011 Elsevier B.V.

Komarneni S.,University Park | Katsuki H.,Saga Ceramics Research Laboratory
Ceramics International | Year: 2010

The role of in situ stirring under microwave-hydrothermal (M-H) conditions on the synthesis of barium titanate was investigated for the first time by powder X-ray diffraction and scanning and transmission electron microscopy. Stirring under M-H conditions in the temperature range of 150-200 °C led to enhanced crystallization of Ba titanate as revealed by yields compared to the static condition. In addition, stirring led to smaller and more uniform crystals under M-H conditions compared to those crystallized without stirring. Powder X-ray diffraction revealed the formation of only cubic polymorph of Ba titanate at or below 200 °C in 4 h with or without in situ stirring under M-H conditions. These results show that stirring is an important parameter during M-H synthesis of nanophase Ba titanate. © 2009 Elsevier Ltd and Techna Group S.r.l.

Papoulis D.,University of Patras | Komarneni S.,Pennsylvania State University | Panagiotaras D.,Technological Educational Institute TEI of Western Greece | Stathatos E.,Technological Educational Institute TEI of Western Greece | And 7 more authors.
Applied Catalysis B: Environmental | Year: 2014

For the first time two different nanoclay minerals were combined with nanophase anatase for the synthesis of three-phase nanocomposites with improved photocatalytic properties. The novel halloysite (H)+palygorskite (Pal)-TiO2 nanocomposites were prepared using palygorskite and halloysite from Greece. Three nanocomposites were synthesized using [Hal+Pal] to TiO2 mass ratios of [10+20]:70, [15+15]:70 and [20+10]:70, respectively by depositing anatase form of TiO2 on the clay surfaces using titanium isopropoxide as a precursor under hydrothermal treatment at 180°C. Phase composition, particle morphology and physical properties of these three-phase nanocomposites were characterized by XRD, ATR-FTIR, SEM, TEM, DR-UV-Vis, N2-adsorption/desorption isotherms. The photocatalytic activities of three-phase clay-titania nanocomposites in decomposing NOx gas and toluene vapor were determined. The three-phase clay-titania nanocomposites showed significantly higher photocatalytic activity in decomposing inorganic and organic pollutants compared to that of either palygorskite- or halloysite-TiO2 nanocomposites under both UV- and visible-light irradiation. These studies led to a new class of clay-based nanocomposite materials with advanced photocatalytic properties. © 2013 Elsevier B.V.

Papoulis D.,University of Patras | Komarneni S.,Pennsylvania State University | Panagiotaras D.,Technological Educational Institute of Patra | Stathatos E.,Technological Educational Institute of Patra | And 7 more authors.
Applied Catalysis B: Environmental | Year: 2013

Two halloysite-TiO2 nanocomposites were prepared with two different tubular halloysite clays by depositing anatase-TiO2 on the halloysite surfaces using titanium isopropoxide under hydrothermal treatment at 180°C. The nanocomposites were characterized by X-Ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), attenuated total reflection using Fourier transform infrared spectroscopy (ATR-FTIR), absorption properties by UV-vis spectroscopy and N2 specific surface area (SSA) analysis by BET method. Good dispersion of 3-10nm TiO2 particles on halloysite external surfaces was achieved in both the halloysite-TiO2 nanocomposites and ATR-FTIR results showed the formation of hydrogen bonding between TiO2 and the outer surfaces of halloysite tubes. After treating with TiO2, both halloysite samples largely showed interparticle mesopores of about 5.7nm. However, the macropores of halloysite (lumen or central hole in halloysite tubes) were not detected probably as a result of plugging of the lumens in halloysite tubes by TiO2 nanoparticles. These nanocomposites were tested for their photocatalytic activities in decomposing NOx gas and toluene. The halloysite-titania samples showed significantly higher activity in decomposing NOx gas under visible-light irradiation (λ>510nm) and UV-visible light irradiation (λ>290nm) compared to that of the standard commercial titania photocatalyst, P25. In addition, composite photocatalyst showed larger catalytic activity either under sunlight or pure UV irradiation in decomposing toluene compared to the commercial titania, P25. Our experimental data suggest that the enhanced photocatalytic activity is related with the good dispersion of the TiO2 nanocrystals on the surface of the clay minerals. © 2012 Elsevier B.V.

Shiraishi A.,Saga Ceramics Research Laboratory | Takeuchi N.,Osaka University | Masui T.,Osaka University | Imanaka N.,Osaka University
RSC Advances | Year: 2015

Novel environment friendly inorganic red pigments, (Bi1-x-yZrxAly)4V2O11+δ (0 ≤ x ≤ 0.15; 0 ≤ y ≤ 0.10), were successfully synthesized by a conventional solid state reaction method, and their colour properties were characterized. The colour of the obtained pigments was dependent on the calcination condition and the sample composition, and the highest red hue was obtained for the (Bi0.92Zr0.07Al0.01)4V2O11.34 pigment calcined at 800 °C for 10 h in a flow of pure O2. The a∗ value corresponding to the red chromaticity of this pigment was +41.9, which was significantly greater than that of the commercial iron oxide pigment (a∗ = +28.9). Bi4V2O11 is considered to be a nontoxic compound, and the other components (Zr and Al) are also safe elements. Therefore, the present pigment could be an attractive candidate as a novel environment friendly inorganic red pigment. This journal is © The Royal Society of Chemistry 2015.

Kawashima M.,Saga University | Kawakita H.,Saga University | Ohto K.,Saga University | Shiwa Y.,Saga Ceramics Research Laboratory
Solvent Extraction Research and Development | Year: 2012

A calix[4]arene carboxylic acid derivative alternatively possessing benzoic acid and two acetic acid groups has been prepared to investigate the extraction behavior for the aluminum group of metals, such as aluminum, gallium, and indium from nitrate and chloride media and to compare with the tetraacetic acid derivative. The present extraction reagent exhibits a simple ion-exchange mechanism for all metals. Both extractants show that the selectivity series is In > Ga ≫ Al in nitrate media, while Ga > In ≫ Al is found for chloride media due to complexation of indium with chloride anions. The stoichiometry of the gallium complex with both extractants, determined by the continuous variation method, was determined to be 1 : 1. The complexation site of the present extractant for gallium was also determined using 1H-NMR spectroscopy. The extraction ability and separation efficiency of both extractants for the three metal ions were estimated by using the half pH values. Stripping of the metal ions loaded on the present extractant with hydrochloric acid was also investigated.

Kamochi N.,Saga Ceramics Research Laboratory | Nishiyama K.,Saga Ceramics Research Laboratory | Katsuki H.,Saga Ceramics Research Laboratory
Nippon Seramikkusu Kyokai Gakujutsu Ronbunshi/Journal of the Ceramic Society of Japan | Year: 2016

The influence of talc addition on the pyroplastic deformation of alumina-strengthened porcelain was investigated in this study. Along with the lower content of feldspar, the addition of talc contributed to the crystallization of the cordierite during the firing process, and the resulting cordierite crystals formed complicated filler structures. The porcelain samples made with the addition of talc showed an unprecedented pyroplastic deformation characteristic with almost no changes in the pyroplastic deformation index value during further firing at over 100°C after the water absorption reached almost zero. This improvement of pyroplastic deformation was thought to synchronize with the crystallization of cordierite. © 2016 The Ceramic Society of Japan. All rights reserved.

Katsuki H.,Saga Ceramics Research Laboratory | Komarneni S.,Pennsylvania State University
Nippon Seramikkusu Kyokai Gakujutsu Ronbunshi/Journal of the Ceramic Society of Japan | Year: 2011

Nano-sized BaTiO3 particles were prepared at 90°C using TiO2 and Ba(OH)2 as precursors by microwave-assisted (M-A) heating and conventional-heating (C-H) processes. Compared to the formation of BaTiO3 particles using the C-H process, the M-A process led to increased rate of formation by about 6 times. BaTiO3 particles of 29nm in average particle size were obtained after treatment for 15min by using microwaves during the heating process at 90°C. The use of microwaves led to the formation of smaller sized particles with narrower particle size distribution compared to that of C-H process. © 2011 The Ceramic Society of Japan.

Hara K.,Japan National Institute of Advanced Industrial Science and Technology | Ichinose H.,Saga Ceramics Research Laboratory | Murakami T.N.,Japan National Institute of Advanced Industrial Science and Technology | Masuda A.,Japan National Institute of Advanced Industrial Science and Technology
RSC Advances | Year: 2014

Potential-induced degradation (PID) in multicrystalline Si photovoltaic (PV) modules was generated by applying -1000 V from an Al plate attached on the cover glass of the module to the Si cell at 85 °C. The solar energy-to-electricity conversion efficiency of the standard Si PV module remarkably decreased from 15.9% to 0.6% after 2 h of the PID test. Increased concentration of Na species on the surface of the Si cell after the PID test was observed by secondary ion mass spectrometry (SIMS) measurement. Our results indicate that high minus voltage stress toward the Si cell causes the diffusion of metal cations, such as Na+, from the front cover glass toward the Si cell, resulting in remarkable decrease in PV performance. PID was significantly prevented by a coating of TiO2-thin film on the cover glass that suppressed the diffusion of Na+, demonstrating an attractive and promising technique for producing low-cost PID-resistant PV modules. © 2014 The Royal Society of Chemistry.

Katsuki H.,Saga Ceramics Research Laboratory | Furuta S.,Saga Ceramics Research Laboratory | Komarneni S.,Pennsylvania State University
Materials Letters | Year: 2012

Nano-sized cubic BaTiO 3 was prepared rapidly at 90 °C using TiO 2 and Ba(OH) 2 as precursors by a home-built semi-continuous microwave-assisted synthesis system. Cubic BaTiO 3 particles of 30 to 50 nm were obtained after treatment for 5 min at 90 °C. The conversion of TiO 2 to BaTiO 3 reached 100% after 15 min. The approximate total energy consumption of microwave irradiation during reaction at 90 °C for 5 min was 118 kJ which was lower than that used by conventional heating (792 kJ) with an oven at 90 °C for 5 min. © 2012 Elsevier B.V. All rights reserved.

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