Examinando por Materia "Oxidation"
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Ítem Caracterización del potencial de generación de acidez en rocas presentes al oriente del municipio de Titiribí, Antioquia(Universidad EAFIT, 2022) Romero Lozano, Angélica María; Villamarín Zamora, Juan Manuel; Gómez Gutiérrez, Diego FelipeThe phenomenon of acid rock drainage (ARD) occurs naturally, mainly from the exposure and oxidation of sulfide minerals in the environment, with the subsequent generation of acid drainage and leaching of associated heavy metals. ARD is time-dependent and involves chemical and biological oxidation, which have effects at a physicochemical level. The municipality of Titiribí is located in southwestern Antioquia, an area with the presence of geological environments that allowed the occurrence of several lithological typologies (igneous, metamorphic and sedimentary rocks), as well as mineral deposits such as the presence of coals. Consequently, there are volumes of rocks of different compositions exposed to the natural environment that can present geochemical behaviors associated to the potential generation of acidity (PGA), which can be intensified due to the tropical climate conditions of the area (temperature, humidity, and rainfall). In this research, results associated with the characterization of the acidity generation potential (PGA) of the different outcropping lithologies and its possible generation and affectation in the hydrological and hydrogeological systems in the environment are obtained.Ítem Degradación de Colorante Amarillo 12 de Aguas Residuales Industriales utilizando Hierro Cero Valente, Peróxido de Hidrógeno y Radiación Ultravioleta(Centro de Informacion Tecnologica, 2016-01-01) Gilpavas, E.; Medina, J.; Dobrosz-Gómez, I.; Gómez, M.Á.; Gilpavas, E.; Medina, J.; Dobrosz-Gómez, I.; Gómez, M.Á.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Procesos Ambientales (GIPAB)The Fenton heterogeneous process in a fluidized bed reactor using Zero Valent Iron (ZVI), in the metallic state, for the treatment of textile wastewater has been used an analyzed. The aim of this work was to optimize the following operating parameters: initial dye concentration, H2O2 concentration, pH, amount of ZVI, and UV radiation, for the removal of dye and organic matter. At first, a fractional factorial experimental design allows defining the most influential factors. After that, they were optimized using the Response Surface Methodology coupled to the Box-Behnken experimental design. The optimal conditions were found to be as follows: initial dye concentration, 881 mg/L; pH 5; ZVI concentration, 5,31 g/L; H2O2 concentration, 0,86 mL/L. At these conditions, the degradation kinetics was performed, reaching 100% and 80,83% of dye and chemical oxygen demand respectively, in 150 minutes of reaction.Ítem Degradación de Tartrazina mediante electro-oxidación(Universidad EAFIT, 2013) Castaño Zuluaga, Andrea; Céspedes Rico, Andrea; Gil Pavas, Edison HernánEste proyecto de grado está conformado por cinco capítulos, el primer capítulo está relacionado con los conceptos generales, se presenta el marco teórico y algunos antecedentes relacionados con la investigación; igualmente, se plantean los objetivos y la justificación del estudio -- En el segundo capítulo se presenta los materiales y métodos implementados en la investigación, para la ejecución de cada uno de los ensayos de laboratorio, los cuales se hicieron basados en el diseño estadístico de experimentos seleccionado -- El tercer capítulo contiene los resultados obtenidos de los experimentos y el análisis de los mismos comparándolos con lo reportado en la literatura -- En el cuarto capítulo, se presenta el diseño conceptual del proceso electro-foto-Fenton a escala industrial con su respectivo análisis económico -- Finalizando, en el capítulo cinco, se presentan las conclusiones y recomendaciones generales de la investigación -- La investigación consiste en optimizar las condiciones de operación del proceso de electro-oxidación usando electrodos de diamante dopados con boro, BDD, con el fin de evaluar la degradación del colorante azoico tartrazina presente en el agua y de esta manera determinar la eficacia del tratamiento -- Los experimentos realizados en el laboratorio, se hicieron un reactor de borosilicato con capacidad de tratamiento de 42 ml de agua -- Se realizaron ensayos preliminares con el fin de identificar los parámetros más importantes respecto a la eficiencia del proceso, mediante un diseño estadístico de experimentos factorial fraccionado, el análisis determinó que los parámetros más influyentes fueron: concentración del colorante, pH de la solución y densidad de corriente -- Las condiciones óptimas de operación, Ci: 30 ppm de tartrazina, i: 5 mA/cm², pH 6, conductividad 1060 S/cm, agitación 340 RPM y concentración de 0,3 mM FeCl2•4H2O, se determinaron con el análisis del diseño de superficie de respuesta, las variables de respuesta fueron el %DC, %DDQO y %DCOT -- Bajo estas condiciones, se realizó el estudio cinético de los procesos de electro-oxidación (EO), electro-Fenton (EF) y electro-foto-Fenton (EFF), y de esta manera se determinó el efecto sinérgico, mediante la incorporación de FeCl2•4H2O y de la radiación UV -- Los resultados obtenidos para cada uno de los procesos para una concentración de colorante de 30 ppm, durante un tiempo de electrólisis de 30 minutos fueron: para el proceso EO %DC 95.87, %DDQO 70 y %DCOT 60; para el proceso EF %DC 88.69, %DDQO 80 y %DCOT 75 y para el proceso EFF %DC 95.48, %DDQO 92.50 y %DCOT 90 -- Por lo tanto, el proceso más eficiente fue el EFF -- Con estos resultados, se diseñó conceptualmente, la planta de tratamiento, para procesar 96 m3/día en un reactor de 15 m3Ítem Envejecimiento termo-oxidativo de asfaltos(Universidad EAFIT, 2014) Gamarra Escamilla, AdrianaÍtem Optimization and toxicity assessment of a combined electrocoagulation, H2O2/Fe2+/UV and activated carbon adsorption for textile wastewater treatment(Elsevier, 2019-02-15) GilPavas, E; Dobrosz-Gomez, I; Gomez-Garcia, MA; GilPavas, E; Dobrosz-Gomez, I; Gomez-Garcia, MA; Universidad EAFIT. Departamento de Ingeniería de Procesos; Procesos Ambientales (GIPAB)In this study, the potential application of sequential Electrocoagulation + Fenton (F) or Photo-Fenton (PF) + Active carbon adsorption (EC + F/PF + AC) processes were analyzed as alternatives for the treatment of an industrial textile wastewater resulting from an industrial facility located in Medellín (Colombia). In order to maximize the organic matter degradation, each step of the treatment was optimized using the Response Surface Methodology. At first, the optimal performance of EC was achieved with Fe electrodes operating at pH = 7, jEC = 10 mA/cm2 and 60 rpm, during 10 min of electrolysis. At these conditions, EC let to remove 94% of the dye's color, 56% of the COD and 54% of the TOC. Next, sequentially applied Fenton or photo-Fenton process (i.e., EC + F/PF), operating at the optimized conditions (pH = 4.3, [Fe2+] = 1.1 mM, [H2O2] = 9.7 mM, stirring velocity = 100 rpm and reaction time = 60 min.), improved the quality of the treated effluent. The EC + F let to achieve total color reduction, as well as COD and TOC removals of 72 and 75%, respectively. The EC + PF reached 100% of color, 76% of COD and 78% of TOC reductions. The EC + F/PF processes were more efficient than EC in elimination of low molecular weight (<5 kDa) compounds from wastewater. Moreover, the BOD5/COD ratio increased from 0.21 to 0.42 and from 0.21 to 0.46 using EC + F and EC + PF processes, respectively. However, EC + F/PF were not fully effective for the removal of acute toxicity to Artemia salina: 20% and 60% of reduction in toxicity using EC + F and EC + PF, respectively, comparing to very toxic (100%) raw textile wastewater. Thus, activated carbon adsorption was applied as an additional step to complete the treatment. After AC adsorption, the acute toxicity decreased to 10% and 0% using EC + F and EC + PF, respectively. The total operational costs, including chemical reagents, electrodes, energy consumption and sludge disposal, were of 1.65 USD/m3 and 2.3 USD/m3 for EC + F and EC + PF, respectively. © 2018 Elsevier B.V.Ítem Optimization and toxicity assessment of a combined electrocoagulation, H2O2/Fe2+/UV and activated carbon adsorption for textile wastewater treatment(Elsevier, 2019-02-15) GilPavas, E; Dobrosz-Gomez, I; Gomez-Garcia, MA; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de ProcesosIn this study, the potential application of sequential Electrocoagulation + Fenton (F) or Photo-Fenton (PF) + Active carbon adsorption (EC + F/PF + AC) processes were analyzed as alternatives for the treatment of an industrial textile wastewater resulting from an industrial facility located in Medellín (Colombia). In order to maximize the organic matter degradation, each step of the treatment was optimized using the Response Surface Methodology. At first, the optimal performance of EC was achieved with Fe electrodes operating at pH = 7, jEC = 10 mA/cm2 and 60 rpm, during 10 min of electrolysis. At these conditions, EC let to remove 94% of the dye's color, 56% of the COD and 54% of the TOC. Next, sequentially applied Fenton or photo-Fenton process (i.e., EC + F/PF), operating at the optimized conditions (pH = 4.3, [Fe2+] = 1.1 mM, [H2O2] = 9.7 mM, stirring velocity = 100 rpm and reaction time = 60 min.), improved the quality of the treated effluent. The EC + F let to achieve total color reduction, as well as COD and TOC removals of 72 and 75%, respectively. The EC + PF reached 100% of color, 76% of COD and 78% of TOC reductions. The EC + F/PF processes were more efficient than EC in elimination of low molecular weight (<5 kDa) compounds from wastewater. Moreover, the BOD5/COD ratio increased from 0.21 to 0.42 and from 0.21 to 0.46 using EC + F and EC + PF processes, respectively. However, EC + F/PF were not fully effective for the removal of acute toxicity to Artemia salina: 20% and 60% of reduction in toxicity using EC + F and EC + PF, respectively, comparing to very toxic (100%) raw textile wastewater. Thus, activated carbon adsorption was applied as an additional step to complete the treatment. After AC adsorption, the acute toxicity decreased to 10% and 0% using EC + F and EC + PF, respectively. The total operational costs, including chemical reagents, electrodes, energy consumption and sludge disposal, were of 1.65 USD/m3 and 2.3 USD/m3 for EC + F and EC + PF, respectively. © 2018 Elsevier B.V.Ítem Thermo-oxidative aging of bitumen(Taylor and Francis Ltd., 2018-07-03) Gamarra, A.; Ossa, E.A.; Gamarra, A.; Ossa, E.A.; Universidad EAFIT. Departamento de Ingeniería de Producción; Materiales de IngenieríaThermo-oxidative bitumen ageing has been commonly recognised as the main cause of asphalt cracking. The effect of thermo-oxidative ageing level on bitumen has been studied in this work by means of a simple and effective mechanical stirring process. Physical characteristics of the material as Softening Point, Penetration and Viscosity were measured to samples with different ageing conditions. Chemical changes in the material were evaluated by means of SARA fractioning to measure the effect of ageing on the fundamental components of bitumen, and Infrared Spectroscopy in order to study the changes found on the oxidation-related compounds of the material. Microstructural changes on the material were evaluated using atomic force microscopy (AFM) finding that the ageing process on bitumen increases the number and size of the phases related to asphaltenes and resins, and decreases the amount of phases related to aromatics. The changes in chemical and physical characteristics of bitumen were found to be strongly dependent on the carbonyl formation. An extension to a previously proposed oxidation kinetics model was used to predict the fast rate (transient) and constant rate (steady-state) oxidation behaviour of bitumen and its relation to physical properties. The thermo-oxidative changes suffered by bitumen are associated with increasing hardening of the material, making it susceptible to cracking when in contact with aggregate as thin films in flexible pavements. © 2016 Informa UK Limited, trading as Taylor & Francis Group.