PHOTOCATALYTIC PERFORMANCE OF SYSTEMS BASED ON URANYL-INCORPORATED SBA-15 MESOPOROUS SILICA.

The present study investigated incorporating uranyl ions into solid porous matrices for long-term storage and, at the same time, the possibility of using excited uranyl ions as a photocatalyst for the degradation of dangerous pollutant molecules that may be ingested or inhaled. As a porous matrix, SBA-15 silica was used. The matrix synthesis consisted in a self-assembly process. The triblock copolymer Pluronic 123(EO20PO70EO20) was used as a template, under acidic conditions. Tetraethoxyorthosilicate played the role of silica source. The uranyl ions were heterogenized onto the large ordered pores of SBA-15 mesoporous silica. These pores served as ideal hosts for the encapsulation of uranyl species due to their high surface area, large pore size and high thermal stability. The samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), diffuse reflectance ultraviolet--visible spectroscopy (DRUV--VIS), and nitrogen adsorption/desorption technique at 77K. The uranyl ions incorporated within the mesopores of silica host matrices served as highly efficient heterogeneous photocatalysts for room-temperature photooxidation of Eosin Y as a reactant in the photocatalytic batch reactor. The results indicate the potential applicability of uranyl encapsulated onto the SBA-15 silica photocatalyst in applications related to wastewater processing under ambient conditions. [ABSTRACT FROM AUTHOR]