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Reducción mejorada por ligando del perclorato en agua con catalizadores heterogéneos Re-Pd/C

Keith D Hurley¹, Yunxia Zhang, John R Shapley

¹Department of Chemistry and Center of Advanced Materials for the Purification of Water with Systems, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.

Journal of the American Chemical Society

|September 24, 2009

Resumen

Nuevos catalizadores heterogéneos bimetálicos reducen efectivamente el perclorato en el agua utilizando dihidrógeno. La actividad del catalizador se correlaciona con la sustitución de piridina, con un sistema basado en dimetilaminopiridina que muestra un rendimiento y una estabilidad superiores.

Área de la Ciencia:

La catálisis es la catálisis.
Química del medio ambiente Química del medio ambiente
Ciencia de los materiales Ciencia de los materiales.

Sus antecedentes:

La contaminación por perclorato en el agua plantea riesgos ambientales y para la salud.
El desarrollo de catalizadores heterogéneos eficientes para la reducción del perclorato es crucial.
Los catalizadores bimetálicos ofrecen propiedades sintonizables para una mayor reactividad.

Objetivo del estudio:

Sintetizar y caracterizar nuevos catalizadores bimetálicos heterogéneos para la reducción del perclorato.
Investigar la influencia de los métodos de preparación del catalizador y la estructura del ligando en la actividad catalítica.
Para evaluar la estabilidad y el rendimiento de los catalizadores bajo diferentes condiciones de pH.

Principales métodos:

Preparación de paladio en catalizadores de carbón activado (Pd/C).
Impregnación de Pd/C con complejos trans-[ReO(2)(py-X)(4)](+) o adsorción de perrenato con ligandos de piridina.
Reducción catalítica del perclorato utilizando dihidrógeno en soluciones acuosas a pH controlado.

Principales resultados:

Ambos métodos de preparación produjeron catalizadores altamente activos para la reducción del perclorato a un pH de 2.7-3.0.
La actividad del catalizador aumentó con los sustituyentes donantes de electrones (X) en el ligando de piridina (H < Me < OMe < NMe(2)).
Los catalizadores preparados por el método (2) demostraron una mayor estabilidad, en particular un sistema con dimetilaminopiridina, estable hasta un pH de 4.5.

Conclusiones:

Los catalizadores bimetálicos Pd-Re son efectivos para la reducción del perclorato en el agua.
El rendimiento del catalizador está significativamente influenciado por las propiedades electrónicas del ligando de piridina y el método de preparación.
El sistema de catalizadores optimizado es prometedor para aplicaciones prácticas en la remediación de aguas.

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