Examinando por Materia "Photochemistry"

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    Ítem
    Multifactorial optimization of the decolorisation parameters of wastewaters resulting from dyeing flowers.
    (IWA PUBLISHING, 2009-01-01) Gil Pavas, Edison; Angel Gomez-Garcia, Miguel; Gil Pavas, Edison; Angel Gomez-Garcia, Miguel; Universidad EAFIT. Departamento de Ingeniería de Procesos; Procesos Ambientales (GIPAB)
    This work deals with the treatment of the wastewaters resulting from the process of dyeing flowers. In some local cases for growing flowers near to Medellin (Colombia), wastewater color was found to be one of the main problems in meeting local effluent standards. Wastewaters were treated by photodegradation process (which includes photocatalysis) to achieve the degradation of dyes mixture and organic matter in the wastewater. A multifactorial experimental design was proposed, including as experimental factors the following variables: pH, and the concentration of both catalyst (TiO(2)) and hydrogen peroxide (H(2)O(2)). According to the obtained results, at the optimized variables values, it is possible to reach a 99% reduction of dyes, a 76.9% of mineralization (TOC) and a final biodegradability of 0.834. Kinetic analysis allows proposing a pseudo first order reaction for the reduction, the mineralization, and the biodegradation processes.
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    Ítem
    Obtención de estructuras de relieve en materiales de registro de haluros de plata
    (Sedoptica, 2013-09-19) Velásquez Prieto, Daniel; Giraldo Castaño, Lady Marcela; Velásquez Prieto, Daniel; Giraldo Castaño, Lady Marcela; Universidad EAFIT. Departamento de Ciencias Básicas; lmgc15@gmail.com; Óptica Aplicada
    Diffraction transmission gratings were recorded in AGFA-8E75 film, chemically treated under processes with D-19 + potassium ferrocyanide and a chemical processing technique proposed for PE-2 film to obtain embossed stripes. Holographic structures were measured topographically by the technique of atomic force microscopy in noncontact mode (NC-AFM) and we observe changes in the depths under variations in exposures and used photochemistry. We find that the best performance in terms of relief depth obtained is given by the conventional process which reached depths between 0.15 m and 0.3 m for spatial frequencies of the order of 400