Photocatalytic degradation of Phenol, Catechol and Hydroquinone over Au-ZnO nanomaterials/Degradacion fotocatalitica de Fenol, Catecol e Hidroquinona sobre nanomateriales Au-ZnO

Au-ZnO nanomaterials were tested in photodegradation reactions performed under UV-Visible light; Phenol, Catechol and Hydroquinone were selected as target molecules, and it was found that Hydroquinone is the most sensitive molecule to be degraded under illumination. The Au addition significantly increases the photocatalytic activity of ZnO in the degradation of the phenolic compounds and the Au content is an important factor influencing the physicochemical properties of the nanomaterials synthesized and therefore the effectiveness of the photocatalytic treatment. The highest effectiveness in the phenolic compounds elimination was achieved by using ZnO modified by the addition of 2 wt.% of gold, this is due to the highest absorption of this material in the visible region of the electromagnetic spectrum. By HPLC analyzes, it was determined that the degradation route of the phenolic compounds depends on the photocatalyst employed in the catalytic reaction and on the substrate to be degraded, thus, Phenol degradation takes place by formation of more intermediate compounds than the observed in Catechol or Hydroquinone photodegradation. Algunos nanomateriales tipo Au-ZnO fueron evaluados en reacciones de fotodegradacion bajo luz UV-Visible; Fenol, Catecol e hidroquinona fueron las moleculas modelo, en general se encontro que la Hidroquinona es la molecula mas sensible a la degradacion bajo iluminacion. La adicion de Au incrementa significativamente la actividad fotocatalitica del ZnO en la degradacion de los compuestos fenolicos y el contenido de Au es un factor con una influencia muy importante sobre las propiedades fisicoquimicas de los nanomateriales sintetizados y sobre la efectividad del tratamiento fotocatalitico. La efectividad mas alta en la eliminacion de los compuestos fenolicos se logro usando ZnO modificado por adicion de 2% en peso de oro, esto se debe a la mayor absorcion que presenta este material en la region visible del espectro electromagetico. Por HPLC, se encontro que la ruta de degradacion de los compuestos fenolicos depende del fotocatalizador empleado en la reaccion y del sustrato a degradar, asi, la degradacion del Fenol se lleva a cabo a traves de la formacion de un mayor numero de compuestos intermediarios que lo observado en la degradacion de Catecol e Hidroquinona.