Examinando por Materia "Kinetic study"

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    Ítem
    The Box-Benkhen experimental design for the optimization of the electrocatalytic treatment of wastewaters with high concentrations of phenol and organic matter.
    (IWA PUBLISHING, 2009-01-01) GilPavas, Edison; Betancourt, Alejandra; Angulo, Monica; Dobrosz-Gomez, Izabela; Angel Gomez-Garcia, Miguel; GilPavas, Edison; Betancourt, Alejandra; Angulo, Monica; Dobrosz-Gomez, Izabela; Angel Gomez-Garcia, Miguel; Universidad EAFIT. Departamento de Ingeniería de Procesos; Procesos Ambientales (GIPAB)
    In this work, the Box-Benkhen experimental Design (BBD) was applied for the optimization of the parameters of the electrocatalytic degradation of wastewaters resulting from a phenolic resins industry placed in the suburbs of Medellin (Colombia). The direct and the oxidant assisted electro-oxidation experiments were carried out in a laboratory scale batch cell reactor, with monopolar configuration, and electrodes made of graphite (anode) and titanium (cathode). A multifactorial experimental design was proposed, including the following experimental variables: initial phenol concentration, conductivity, and pH. The direct electro-oxidation process allowed to reach ca. 88% of phenol degradation, 38% of mineralization (TOC), 52% of Chemical Oxygen Demand (COD) degradation, and an increase in water biodegradability of 13%. The synergetic effect of the electro-oxidation process and the respective oxidant agent (Fenton reactant, potassium permanganate, or sodium persulfate) let to a significant increase in the rate of the degradation process. At the optimized variables values, it was possible to reach ca. 99% of phenol degradation, 80% of TOC and 88% of COD degradation. A kinetic study was accomplished, which included the identification of the intermediate compounds generated during the oxidation process.
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    Ítem
    Decolorization and mineralization of Diarylide Yellow 12 (PY12) by photo-Fenton process: the Response Surface Methodology as the optimization tool.
    (IWA PUBLISHING, 2012-01-01) GilPavas, Edison; Dobrosz-Gomez, Izabela; Angel Gomez-Garcia, Miguel; GilPavas, Edison; Dobrosz-Gomez, Izabela; Angel Gomez-Garcia, Miguel; Universidad EAFIT. Departamento de Ingeniería de Procesos; Procesos Ambientales (GIPAB)
    The Response Surface Methodology (RSM) was applied as a tool for the optimization of the operational conditions of the photo-degradation of highly concentrated PY12 wastewater, resulting from a textile industry located in the suburbs of Medellin (Colombia). The Box-Behnken experimental Design (BBD) was chosen for the purpose of response optimization. The photo-Fenton process was carried out in a laboratory-scale batch photo-reactor. A multifactorial experimental design was proposed, including the following variables: the initial dyestuff concentration, the H(2)O(2) and the Fe(+2) concentrations, as well as the UV wavelength radiation. The photo-Fenton process performed at the optimized conditions resulted in ca. 100% of dyestuff decolorization, 92% of COD and 82% of TOC degradation. A kinetic study was accomplished, including the identification of some intermediate compounds generated during the oxidation process. The water biodegradability reached a final DBO(5)/DQO = 0.86 value.
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    Ítem
    Kinetic study on HCN volatilization in gold leaching tailing ponds
    (Elsevier Ltd, 2017-08-15) Dobrosz-Gómez, I.; Ramos García, B.D.; GilPavas, E.; Gómez García, M.Á.; Dobrosz-Gómez, I.; Ramos García, B.D.; GilPavas, E.; Gómez García, M.Á.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Procesos Ambientales (GIPAB)
    In this work, the detailed analysis of HCN volatilization, taking place in tailing storage facilities, was made. Volatilization experiments were performed at conditions typical of gold leaching industrial tailing ponds. The meticulous statistical analysis (including full factorial 33 experimental design) let to determine the variables and their interactions affecting the percentage of HCN volatilization. Volatilization tests were performed in an open, temperature-controlled, continuously-stirred batch reactor. The percentage of HCN volatilization was directly proportional to the temperature and temperature-pH interaction and inversely proportional to the pH, cyanide concentration, and pH-pH and temperature-cyanide concentration interactions. HCN volatilization was promoted at acidic conditions. A first order rate law was used to represent the volatilization rate. The specific rate constant (k) was found to be following function of temperature and pH: k(T,pH) = Ao.exp(-18760/T), where: In(A(0)) = (0.11 +/- 0.11)-pH + (58.08 +/- 0.16). The obtained kinetic model represented properly (R-2 = 0.90) experimental data in a wide range of industrial conditions: cyanide concentration (300-2000 mg.L-1), pH (3-9), and temperature (16-20 degrees C). The increase in temperature, from 16 to 20 C, let to the increase in k, by a factor of ca. 2.5 +/- 0.8. The increase in solution pH, from 3 to 9, provoked its decrease, by a factor of ca. 1.9 +/- 0.3.
  • No hay miniatura disponible
    Ítem
    Kinetic study on HCN volatilization in gold leaching tailing ponds
    (Elsevier Ltd, 2017-08-15) Dobrosz-Gómez, I.; Ramos García, B.D.; GilPavas, E.; Gómez García, M.Á.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de Procesos
    In this work, the detailed analysis of HCN volatilization, taking place in tailing storage facilities, was made. Volatilization experiments were performed at conditions typical of gold leaching industrial tailing ponds. The meticulous statistical analysis (including full factorial 33 experimental design) let to determine the variables and their interactions affecting the percentage of HCN volatilization. Volatilization tests were performed in an open, temperature-controlled, continuously-stirred batch reactor. The percentage of HCN volatilization was directly proportional to the temperature and temperature-pH interaction and inversely proportional to the pH, cyanide concentration, and pH-pH and temperature-cyanide concentration interactions. HCN volatilization was promoted at acidic conditions. A first order rate law was used to represent the volatilization rate. The specific rate constant (k) was found to be following function of temperature and pH: k(T,pH) = Ao.exp(-18760/T), where: In(A(0)) = (0.11 +/- 0.11)-pH + (58.08 +/- 0.16). The obtained kinetic model represented properly (R-2 = 0.90) experimental data in a wide range of industrial conditions: cyanide concentration (300-2000 mg.L-1), pH (3-9), and temperature (16-20 degrees C). The increase in temperature, from 16 to 20 C, let to the increase in k, by a factor of ca. 2.5 +/- 0.8. The increase in solution pH, from 3 to 9, provoked its decrease, by a factor of ca. 1.9 +/- 0.3.
  • No hay miniatura disponible
    Ítem
    Mineralization of cyanide originating from gold leaching effluent using electro-oxidation: multi-objective optimization and kinetic study
    (SPRINGER, 2020-01-01) Dobrosz-Gómez I.; Gómez García M.Á.; Gaviria G.H.; GilPavas E.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de Procesos
    Abstract: This study examines the electro-oxidation (EO) of cyanide originating from an industrial plant´s gold leaching effluent. Experiments were carried out in a laboratory-scale batch cell reactor. Monopolar configuration of electrodes consisting of graphite (anode) and aluminum (cathode) was employed, operating in galvanostatic mode. Response Surface Methodology (RSM), based on a Box–Behnken experimental Design (BBD), was used to optimize the EO operational conditions. Three independent process variables were considered: initial cyanide concentration ([CN-]0 = 1000–2000 mg L-1), current density (J =7–107 mA cm-2), and stirring velocity (? = 250–750 rpm). The cyanide conversion (XCN-), Chemical Oxygen Demand (COD) removal percentage (%RCOD), and specific Energy Consumption per unit mass of removed cyanide (EC) were analyzed as response variables. Multi-objective optimization let to establish the most effective EO conditions ([CN-]0 = 1000 mg L-1, J = 100 mA cm-2 and ? = 750 rpm). The experimental data (XCN-, %RCOD, and EC) were fitted to second-order polynomial models with adjusted correlation coefficients (Radj2) of ca. 98, 99 and 87%, respectively. The kinetic analysis, performed at optimal EO operational conditions, allowed determination of time required to meet Colombian permissible discharge limits. The predictive capacity of kinetic expressions was verified against experimental data obtained for gold leaching effluent. Total cyanide removal and 96% of COD reduction were obtained, requiring EC of 71.33 kWh kg-1 and 180 min. The BOD5 (biological oxygen demand)/COD ratio increased from 4.52 × 10-4 to 0.5573, confirming effluent biodegradability after EO treatment. Graphic Abstract: [Figure not available: see fulltext.]The variation of cyanide (CN-), cyanate (CNO-) and ammonium (NH4 +) ions concentrations vs. time at alkaline conditions. EO operational conditions: [CN-]0 = 1000 mg/L, J = 100 mA/cm2 , ? = 750 rpm, [NaCl] = 0.15 M and pH 11.1. © 2020, Springer Nature B.V.
  • No hay miniatura disponible
    Ítem
    Mineralization of cyanide originating from gold leaching effluent using electro-oxidation: multi-objective optimization and kinetic study
    (SPRINGER, 2020-01-01) Dobrosz-Gómez I.; Gómez García M.Á.; Gaviria G.H.; GilPavas E.; Dobrosz-Gómez I.; Gómez García M.Á.; Gaviria G.H.; GilPavas E.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Procesos Ambientales (GIPAB)
    Abstract: This study examines the electro-oxidation (EO) of cyanide originating from an industrial plant´s gold leaching effluent. Experiments were carried out in a laboratory-scale batch cell reactor. Monopolar configuration of electrodes consisting of graphite (anode) and aluminum (cathode) was employed, operating in galvanostatic mode. Response Surface Methodology (RSM), based on a Box–Behnken experimental Design (BBD), was used to optimize the EO operational conditions. Three independent process variables were considered: initial cyanide concentration ([CN-]0 = 1000–2000 mg L-1), current density (J =7–107 mA cm-2), and stirring velocity (? = 250–750 rpm). The cyanide conversion (XCN-), Chemical Oxygen Demand (COD) removal percentage (%RCOD), and specific Energy Consumption per unit mass of removed cyanide (EC) were analyzed as response variables. Multi-objective optimization let to establish the most effective EO conditions ([CN-]0 = 1000 mg L-1, J = 100 mA cm-2 and ? = 750 rpm). The experimental data (XCN-, %RCOD, and EC) were fitted to second-order polynomial models with adjusted correlation coefficients (Radj2) of ca. 98, 99 and 87%, respectively. The kinetic analysis, performed at optimal EO operational conditions, allowed determination of time required to meet Colombian permissible discharge limits. The predictive capacity of kinetic expressions was verified against experimental data obtained for gold leaching effluent. Total cyanide removal and 96% of COD reduction were obtained, requiring EC of 71.33 kWh kg-1 and 180 min. The BOD5 (biological oxygen demand)/COD ratio increased from 4.52 × 10-4 to 0.5573, confirming effluent biodegradability after EO treatment. Graphic Abstract: [Figure not available: see fulltext.]The variation of cyanide (CN-), cyanate (CNO-) and ammonium (NH4 +) ions concentrations vs. time at alkaline conditions. EO operational conditions: [CN-]0 = 1000 mg/L, J = 100 mA/cm2 , ? = 750 rpm, [NaCl] = 0.15 M and pH 11.1. © 2020, Springer Nature B.V.