Aroma y Marabú: dos precursores interesantes en la producción de carbones activados para la protección ambiental
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Fecha
2005-06-25
Autores
Pérez de Armas, Andy Jorge
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Editor
Universidad Central "Marta Abreu" de las Villas
Resumen
En este trabajo se estudia la factibilidad de preparar carbones activados empleando como materias primas el producto sólido de la pirólisis del Marabú y la Aroma por activación “física” con vapor de agua. Se analizan las propiedades de los diferentes carbones mediante la realización de ensayos químicos (análisis inmediato y elemental) y químico - físicos (índices de azul de metileno, índice de yodo, pH, densidad aparente, curvas cinéticas de adsorción de los metales pesados Ni2+, Pb2+, Cd2+ a 25°C y 60°C y adsorción de N2 a 77K para determinar las características texturales de los carbones activados). Se estudió fundamentalmente la influencia de las distintas temperaturas (600 a 800°C) y tiempos de activación (60 a 120 min.) sobre las diferentes variables respuesta estudiadas. Se obtuvo que tanto los recursos como el agente activante empleado resultaron adecuados para preparar carbones activados con una excelente capacidad de adsorción. Los mejores resultados se obtuvieron para el Marabú a 800°C y 60 min de activación con buenos rendimientos y 800°C y 90 min para la Aroma con rendimientos inferiores al anterior. Se encontró que los resultados experimentales de equilibrio de las curvas cinética de adsorción del sistema ión metálico-carbón de Marabú a los diferentes tiempos de contacto estudiados se ajustaron de manera satisfactoria al modelo de Langmuir, demostrando características favorables como adsorbente. Se determinaron los parámetros químico – físicos del proceso de adsorción según el modelo matemático encontrado, como la Ea(Kj/mol) y los coeficientes de difusión externa e interna así como las constantes de velocidades respectivas para cada proceso. Se encontró por el método de la adsorción de N2 a 77K que la superficie específica del carbón 7 del Marabú era 550 m2/g con un porciento de microporos de 87% y un radio medio de poros de 1.1 nm. Finalmente se comparó los resultados de la caracterización textural del carbón obtenido con un carbón activado comercial de coco y arrojó resultados alentadores ya que el porciento de microporos es muy similar aunque difieren algo en su superficie específica siendo la del carbón de coco mayor.
In this work the feasibility is studied of preparing activated coal using as matters cousins the solid product of the pyrolysis of the Marabu and the Aroma for activation "physics" with vapor of water. The properties of the different coal are analyzed by means of the realization of chemical rehearsals (immediate and elementary analysis) and chemical - physical (indexes of blue of metilene, index of iodine, pH, apparent density, you curve kinetic of adsorption of the heavy metals Ni2+, Pb2+ and Cd2+ to 25°C and 60°C and adsorption of N2 at 77K to determine the textural characteristics of the activated coal). It was studied the influence of the different temperatures fundamentally (600 at 800°C) and times of activation (60 to 120 min.) on the studied different variable answer. It was obtained that as much the resources as the agent used activante were appropriate to prepare coal activated with an excellent capacity of adsorption. The best results were obtained for the Marabu to 800°C and 60 activation min with good yields and 800°C and 90 min for the Aroma with inferior yields to the previous one. It was found that the experimental results of balance of the kinetic curves of adsorption system ion metallic-coal of Marabu at the different studied times of contact were adjusted from a satisfactory way to the pattern of Langmuir, demonstrating characteristic favorable as adsorber. The parameters chemist were determined - physical of the process of adsorption according to the opposing mathematical pattern, as the Ea(Kj/mol) and the coefficients of external and internal diffusion as well as the constants of respective speeds for each process. It was for the method of the adsorption from N2 to 77K that the specific surfaces of the coal 7 of the Marabu were 550 m2/g with a percent of micropores of 87% and a half radius of pores of 1.1 nm. Finally the results of the textural characterization of the coal obtained with a commercial activated coal of coco was compared and it threw encouraging results since the micropores percent it is very similar although they differ something in their specific surface being that of the coal of more coconut.
In this work the feasibility is studied of preparing activated coal using as matters cousins the solid product of the pyrolysis of the Marabu and the Aroma for activation "physics" with vapor of water. The properties of the different coal are analyzed by means of the realization of chemical rehearsals (immediate and elementary analysis) and chemical - physical (indexes of blue of metilene, index of iodine, pH, apparent density, you curve kinetic of adsorption of the heavy metals Ni2+, Pb2+ and Cd2+ to 25°C and 60°C and adsorption of N2 at 77K to determine the textural characteristics of the activated coal). It was studied the influence of the different temperatures fundamentally (600 at 800°C) and times of activation (60 to 120 min.) on the studied different variable answer. It was obtained that as much the resources as the agent used activante were appropriate to prepare coal activated with an excellent capacity of adsorption. The best results were obtained for the Marabu to 800°C and 60 activation min with good yields and 800°C and 90 min for the Aroma with inferior yields to the previous one. It was found that the experimental results of balance of the kinetic curves of adsorption system ion metallic-coal of Marabu at the different studied times of contact were adjusted from a satisfactory way to the pattern of Langmuir, demonstrating characteristic favorable as adsorber. The parameters chemist were determined - physical of the process of adsorption according to the opposing mathematical pattern, as the Ea(Kj/mol) and the coefficients of external and internal diffusion as well as the constants of respective speeds for each process. It was for the method of the adsorption from N2 to 77K that the specific surfaces of the coal 7 of the Marabu were 550 m2/g with a percent of micropores of 87% and a half radius of pores of 1.1 nm. Finally the results of the textural characterization of the coal obtained with a commercial activated coal of coco was compared and it threw encouraging results since the micropores percent it is very similar although they differ something in their specific surface being that of the coal of more coconut.
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Palabras clave
Carbones Activados, Pirólisis/análisis, Pyrolysis /analysis, Ensayos Químicos, Chemical Rehearsals