Examinando por Materia "Activated carbon"

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    Characterization of activated carbon synthesized at low temperatur e fr om cocoa shell ( Theobroma cacao ) for adsorbing amoxicillin.
    (Universidad del Valle, 2017-07-01) Tejada, Candelaria N.; Almanza, Diego; Villabona, Angel; Colpas, Fredy; Granados, Clemente
    (Eng) The objective of the present investigation was to synthesize and characterize activated carbon obtained at low temperature from cocoa shell (Theobroma cacao), which was modified with zinc chloride (ZnCl2) for its use in the removal of amoxicillin. Biomass was characterized by elemental analysis and activated carbon by scanning electron microscopy (SEM), X-ray diffraction (XRD) and surface area analysis (BET) in order to determine the chemical composition, morphological and structural characteristics. In the molecular adsorption tests of amoxicillin, an aqueous solution with a concentration of 20ppm of the contaminant at pH 6 and 9 was used, to which 5g of the adsorbent material impregnated with zinc chloride was added at 1: 3 and 1: 4 ratios. . For the 1: 3 and 1: 4 activated carbons, surface areas of 287.5 m2 / g and 205.4 m2 / g were reached respectively, with average pore sizes of 3 to 4 nm. The percentage of removal of amoxicillin was influenced by the pH of the solution to be treated, reaching the highest percentages at acidic pH, the removal values ​​reached for activated carbon 1: 3 were 75.4% and 67.2%, while for activated carbon 1: 4 they were 65.2% and 56.7% for solutions pH 6 and 9, respectively. It is concluded that the activated carbon obtained at low temperature is a good material to remove amoxicillin in solution.
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    Obtención de carbones activados a partir de semillas de eucalipto, por activación química con H3PO4. Caracterización y evaluación de la capacidad de absorción de fenol desde solución acuosa.
    (2015-05-11) Rincón Silva, Nelson G.; Ramírez Gómez, Wandy M.; Mojica Sánchez, Lizeth C.; Blanco Martínez, Diego A.; Giraldo, Liliana; Moreno Piraján, Juan C.
    Resumen Se sintetizo carbón activado a partir de cáscara de semillas de eucalipto (Eucalyptus globulus Labil), por el método de activación química empleando como agente activante ácido fosfórico, a dos diferentes concentraciones; 30 y 80 % v/v. Los carbones se caracterizaron texturalmente mediante fisisorción de N2, se determinó la superficie específica aparente por el método B.E.T., donde se obtuvieron valores de 2009 y 1027 m2 g-1, se utilizó la ecuación Dubinin-Radushkevich para obtener el volumen de microporo donde se reportan valores de 0.65 y 0.32 cm3 g-1. Se determinó mediante el método Bohem que los carbones son de carácter ácido, aspecto corroborado por la determinación del pH en el punto de carga cero. Se establecieron interacciones energéticas de los sólidos frente a soluciones de HCl y NaOH mediante calorimetría de inmersión, encontrando gran correlación con el contenido de grupos ácidos y básicos de los sólidos. Finalmente se evaluó la capacidad de adsorción de los sólidos con fenol desde solución acuosa, ya que este es un contaminante prioritario, donde se evidenció gran capacidad de adsorción de los dos carbones debido a las amplias áreas superficiales, volúmenes de microporo y la química superficial de los sólidos. Abstract Activated carbons were prepared from shell Eucalyptus (Eucalyptus globulus Labil) by chemical activation using as activating agent solutions of phosphoric acid, at two different concentrations; 30 and 80% v/v. Carbons were texturally characterized by N2 physisorption, the apparent surface area was determined by B.E.T., method, values obtained were 2009 and 1027 m2 g-1. Dubinin-Radushkevich equation was used to obtain the micropore volume with values of 0.65 and 0.32 cm3 g-1. Boehm method established that the carbons are acidic aspect confirmed by determining the point of zero charge. Solid energetic interactions against HCl and NaOH solutions were established by immersion calorimetry finding great correlation with the content of acidic and basic groups of the solids. Finally, the adsorption capacity of the solid was evaluated with phenol from aqueous solution since this is a priority pollutant, where high adsorption capacity of the two carbons was evident due to the large surface area, micropore volume and surface chemistry of solids.
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    Pt and Pd on activated carbon for oxidation of 5-hydr oxymethylfurfural to 2,5-furandicarboxylic acid
    (Universidad del Valle, 2017-07-01) Sanabria, Lyda; Lederhos, Cecilia; Quiroga, Mónica; Cubillos, Jairo; Rojas, Hugo; Martinez, José J.
    (Eng) In this work the transformation in liquid phase of 5-hydroxymethylfurfural (5-HMF) to 2,5-furandicarboxylic acid was studied with the use of Pt and Pd catalysts supported on activated carbon with the presence of NaOH or CaCO3. The catalysts were characterized by H2 chemisorption at room temperature, X-ray spectroscopy (XPS) and thermogravimetric analysis (TGA). The results indicate that the particle size of the catalysts follows the order PtCl / C