Structural Changes by Thermal Treatment up to Glass Obtention of P2O5-Na2O-CaO-SiO2 Compounds with Bioglass Composition Types

P2O5-Na2O-CaO-SiO2 compounds are the base of certain glass types. Glasses are solids obtained by fast cooling of melted mix of certain compounds. Different compositions give origin to many products with a variety of applications such as: bottles, coatings, windows, tools for chemical industry, laboratory equipment, optics, as bioceramics, etc. The aim of this work was to analyze structural changes of different composition in the P2O5-Na2O-CaO-SiO2 systems thermally treated up to 1250˚C, that is to say, before glass formation, by X ray diffraction. Intermediate and final developed phases up to 1100˚C thermal treatment in samples were generated as a function of Na2O/CaO (1 and 1.62) and P2O5/Na2O ratios (0, 0.2 and 0.245). High- and low-combeites, calcium and sodium-calcium silicate were found at the highest studied temperature.Fil: Volzone, Cristina. Provincia de Buenos Aires. Gobernación. Comision de Invest.científicas. Centro de Tecnología de Recursos Minerales y Ceramica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - la Plata. Centro de Tecnología de Recursos Minerales y Ceramica; ArgentinaFil: Stábile, Franco Matías. Provincia de Buenos Aires. Gobernación. Comision de Invest.científicas. Centro de Tecnología de Recursos Minerales y Ceramica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - la Plata. Centro de Tecnología de Recursos Minerales y Ceramica; Argentin

Nanoclay as Adsorbent: Evaluation for Removing Dyes Used in the Textile Industry

The dyes commonly used in the textile industry have structural resonant valence distribution, within a complex molecule, which determines the color of the dyes. The coloring is produced by chromospheres holding radiation in UV-visible range. Besides coloring, these compounds can be found in waste water and cause serious problems in living organisms, because their biodegradation products may be a source of toxic substances such as amines, which are generated from the characteristic azo chromospheres groups in most of the dyes. Current treatments for color removal from hazardous waste from these materials are complex and costly, for this reason some industries do not treat the wastes generated during the staining step. The aim of this study is to evaluate the use of nanoclay as adsorbents for dye used in the textile industry. The dyes used in this work are commercially known as: Orange GR, Black GN an African Brown. Nanoclay was obtained by bentonite treated with organic cation. The retention of the dye was evaluated by measurements in the UV-visible spectrum by using a HP-8354 equipment.Fil: Martínez Stagnaro, Susana Yamila. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Comahue. Facultad de Ingeniería. Asentamiento Universidad Zapala; ArgentinaFil: Volzone, Cristina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Tecnología de Recursos Minerales y Cerámica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Tecnología de Recursos Minerales y Cerámica; ArgentinaFil: Huck, Lucas Ruben. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Tecnología de Recursos Minerales y Cerámica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Tecnología de Recursos Minerales y Cerámica; Argentin

Sorption Water By Modified Bentonite

In order to improve adsorptive properties and provide a viable alternative to humidity control techniques, the desiccants can be modified with chemical aggregates such as calcium chloride (CaCl2), the latter often used as dehydrating due to its hygroscopicity and low cost. Its use as a drying agent has disadvantages because of its particles form a liquid film. However, the CaCl2 may be mixed with other materials for preparing desiccant products. In this work we studied, at 298 K and different relative humidities (RH), the adsorption processes of desiccants mixtures composed of a bentonite clay Argentinian and CaCl2. The results showed a better performance of the desiccant mixture with respect to natural clay in the whole HR working range. It was also observed that addition of CaCl2 favors adsorptive properties with respect to a purification treatment.Fil: Castrillo, Natalia Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; Argentina. Universidad Catolica de Salta. Consejo de Investigaciones; ArgentinaFil: Mercado, Adela Isabel Guadalupe. Universidad Catolica de Salta. Consejo de Investigaciones; Argentina. Universidad Nacional de Salta. Facultad de Ciencias Exactas; ArgentinaFil: Volzone, Cristina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Tecnología de Recursos Minerales y Cerámica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Tecnología de Recursos Minerales y Cerámica; Argentin

Bioactivity of leucite containing glass-ceramics using natural raw materials

Glass compositions were carefully prepared, using natural quartz and potassium feldspar as a part of the starting raw materials. The solids were prepared so as to have theoretical stoichiometric leucite and 45S5 Bioglass in different L/Bg weight ratios between 0.43-1.00. Novel bioactive glass-ceramics, containing leucite, sodium calcium silicate and silicorhenanite, confirmed by XRD and FTIR, were obtained. Bioactivity tests were carried out on powdered and sintered disks forms. The immersion time was up to 25 days. Apatite formation on powders was studied by FTIR, and XRD and SEM were used to study bioactivity on disks. The materials developed an apatite layer on their surfaces within 6 days of immersion in simulated body fluid. The glass-ceramic with L/Bg ratio= 0.43 presented an apatite layer on all its surface, not so for the samples with 0.66 and 1.00 ratios, on which such layer was peeled off in most part of their surfaces.Centro de Tecnología de Recursos Minerales y Cerámic

Nuevo material compuesto adsorbente SiO2C

The present work is about the development of a Novel Composite that has several properties in only one material. This material is composed by a silica network with a sharpened pore size distribution - diameter near 1000 Å - intercrossed with another carbon network that has carbonaceous microdomains of high activity. The first network facilitates the entrance of big molecules to the interior of the material grains so they quickly reach the active sites of the carbonous network, minimizing the diffusional resistance observed when high performance activated carbons are used in adsorption processes or catalytic applications. These two intercrossed structures are self-supporting and independent among them, so one from the other can be isolated without losing the original shape and volume of the starting composite, then, their possible uses may be multiplied. The Novel Composite is stable with respect to other support or adsorbent materials due to its high obtention temperature (1550 °C). The obtention methods of the composite and its isolated structures are described. The material was characterized by different techniques (XRD, IR, Loss on ignition, pore size distribution, specific surface area, adsorption desorption isotherms, methylene blue adsorption and SEM).Facultad de Ingenierí

Surface modification after ethanol wet milling: A comparison between pristine glasses produced from natural minerals and analytical grade raw materials

Four glass compositions were produced taking into account different theoretical Leucite (KAlSi2O6)/Bioglass 45S5 (45% SiO2, 24.5% Na2O, 24.5% CaO, 6% P2O5) ratios using analytical grade reagents only; and replacing some of the reagents by natural minerals, all that were found to be bioactive when they were transformed to glass ceramics. Glasses of particle size below 174 μm were wet milled using ethanol in a high energy planetary ball mill. After wet milling, samples with 25 and 30% of theoretical Leucite content using reagents grade raw materials showed a higher dissolution rate in comparison to the same glasses made from natural mineral, while no differences were found on glasses with 40 and 50% of Leucite theoretical content. Samples with higher dissolution showed a crystalline carbonate phase named Pirssonite on its surface, while on the rest of samples amorphous carbonates were present.Fil: Stábile, Franco Matías. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Tecnología de Recursos Minerales y Cerámica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Tecnología de Recursos Minerales y Cerámica; ArgentinaFil: Rodríguez Aguado, Elena. Universidad de Málaga; EspañaFil: Rodríguez Castellón, Enrique. Universidad de Málaga; EspañaFil: Volzone, Cristina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Tecnología de Recursos Minerales y Cerámica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Tecnología de Recursos Minerales y Cerámica; Argentin

Adsorption of anionic dyes monoazo and diazo using organo-bentonite

Adsorption of orangeand yellow dyes, containing mono- and di-azoic groups, respectively, werestudied by the use of a natural and organo-bentonite, which was obtained bytreatment with hexadecyl-trimethyl-ammonium bromide. Two different bentonitesfrom Argentina were used. X-ray diffraction, UV-visible spectrometry, infraredspectrometry and thermal analysis were used for the characterizations. Theresults were interpreted using isotherms that fit properly to the mathematicalmodel of Langmuir. The structural and physicochemical properties of the clay,and the arrangement of HDTMA+ in the interlayer of the smectites,the main clay mineral composition of the bentonites, were responsible for theretention of dyes. The retention of the azo dyes not only increased with theHDTMA+ modification of the bentonites but also depended on the claymineral (smectite types) composition of the pristine bentonite.Fil: Martínez Stagnaro, Susana Yamila. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación y Desarrollo en Ingeniería de Procesos, Biotecnología y Energías Alternativas. Universidad Nacional del Comahue. Instituto de Investigación y Desarrollo en Ingeniería de Procesos, Biotecnología y Energías Alternativas; Argentina. Universidad Nacional del Comahue. Facultad de Ingeniería. Asentamiento Universidad Zapala; ArgentinaFil: Volzone, Cristina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Tecnología de Recursos Minerales y Cerámica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Tecnología de Recursos Minerales y Cerámica; Argentin

Biovidrios y vitrocerámicos bioactivos sintetizados parcialmente con materiales naturales: Un desafío actual

Los biovidrios y vitro-cerámicos bioactivos generalmente son clasificados como cerámicos funcionales, y están destinados a reparar o reemplazar tejidos del cuerpo. El desafío consiste en hacer uso de ciertas materias primas naturales (minerales de alta pureza) y obtener los biomateriales mencionados para aplicaciones médicas, los cuales deberán cumplir estrictamente aspectos de biocompatibilidad. Vidrios y vitrocerámicos preparados en el laboratorio mostraron actividad después del contacto con una solución que simula el fluido corporal, debido a la presencia de hidroxiapatita sobre la superficie sólida. Sin embargo, importantes ensayos específicos deberán realizarse antes del uso médico de estos materiales preparados parcialmente con minerales naturales.Bioglass and bioactive glass-ceramics are often classified as functional ceramics, and they are used for repairing or replacing bodily tissue. The challenge referred to consists of using certain raw materials from nature (high-purity minerals) in the making of the aforementioned biomaterials for medical applications. These materials must strictly comply with aspects of biocompatibility. Laboratorymade glass and glass-ceramics showed activity after contact with a solution that simulates bodily fluid (SBF) due to the presence of hydroxyapatite on solid surface. However, specific tests of importance should be performed before the medical use of these materials, which are partially prepared with natural minerals.Fil: Volzone, Cristina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Tecnología de Recursos Minerales y Cerámica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Tecnología de Recursos Minerales y Cerámica; Argentin

Los reservorios de agua en los contextos domésticos de la sociedad prehispánica (Belén)

Fil: Balesta, Bárbara. Laboratorio de Análisis Cerámico (LAC). Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Zagorodny, Nora Inés. Laboratorio de Análisis Cerámico (LAC). Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Volzone, Cristina. Centro de Tecnología de Recursos Minerales y Cerámica (CETMIC). La Plata; Argentin

Uptake of acid black 210 dye by organo-montmorillonite clay minerals

Two clays rich in montmorillonite were modified and used as adsorbents. The clay minerals were modified with hexadecylpyridinium cation (HDP+) in order to obtain organo-montmorillonites, which were used for retaining acid black 210 dye from water solution. This dye is frequently used in tanning industry. The retentions of the anionic dye by organo-montmorillonites were evaluated by using complete UV-visible spectrum, analyzing the concentrations of dye solutions before (50 mg/L) and after the contact with the adsorbent. The solids were characterized by X-ray diffraction (XRD) and infrared analyses (FT-IR). The interlayer spacing of the montmorillonites increased, after organic cation exchange, from 13.0-14.9 Å to 19.0-22.0 Å and allowed the uptake of acid black 210 dye. The most disordered arrangement of HDP in montmorillonite, deduced by XRD and FT-IR analyses, was better for higher retentions of acid black dye