A composite heterogeneous photocatalyst based on silver bromide was prepared by a reaction of silver exchanged zirconium phosphate (ZrP) and HBr. The ZrP/AgBr composite containing 53 wt% AgBr was tested in the photocatalytic degradation of Rhodamine B (RhB) and exhibited higher catalytic activity with respect to pure AgBr. As a matter of fact, the time needed to achieve a percentage of chromophore cleavage of about 90% was 3 min for the composite versus the 30 min needed for pure AgBr. The ZrP/AgBr composite turned out to be stable for at least three consecutive cycles. The UV-Vis spectra of the RhB solution, recorded at different irradiation times, were also decomposed and the concentration of the species formed by de-ethylation and cleavage processes during photocatalysis were calculated; the data obtained for the AgBr-based catalysis were also compared with those for the AgCl-based catalysis, and the degradation mechanism was suggested for both catalytic systems.
De-Ethylation and Cleavage of Rhodamine B by a Zirconium Phosphate/Silver Bromide Composite Photocatalyst
Monica Pica
;Anna Donnadio;Pier Luigi Gentili;Morena Nocchetti;Mario Casciola
2019
Abstract
A composite heterogeneous photocatalyst based on silver bromide was prepared by a reaction of silver exchanged zirconium phosphate (ZrP) and HBr. The ZrP/AgBr composite containing 53 wt% AgBr was tested in the photocatalytic degradation of Rhodamine B (RhB) and exhibited higher catalytic activity with respect to pure AgBr. As a matter of fact, the time needed to achieve a percentage of chromophore cleavage of about 90% was 3 min for the composite versus the 30 min needed for pure AgBr. The ZrP/AgBr composite turned out to be stable for at least three consecutive cycles. The UV-Vis spectra of the RhB solution, recorded at different irradiation times, were also decomposed and the concentration of the species formed by de-ethylation and cleavage processes during photocatalysis were calculated; the data obtained for the AgBr-based catalysis were also compared with those for the AgCl-based catalysis, and the degradation mechanism was suggested for both catalytic systems.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.