Time filter

Source Type

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. Source

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. Source

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. Source

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. Source

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. Source

Discover hidden collaborations