Enhancement of photocatalytic activity in UV-illuminated tin dioxode/aluminum oxide system in aqueous 4-nitrophenol

A modified tin dioxide/aluminum oxide was prepared by co-precipitation, and its photocatalytic activity was measured. Tin dioxide modified by adding aluminum oxide had a higher photocatalytic activity than other photocatalysts in this study, especially at pH 7. A mass balance for carbon with UV-254 nm/SnO₂/Al₂O₃ system at pH 7 indicated that the amount of the intermediate increased with reaction time, but decreased after 120 min of photodegradation. The results reveal that the photocatalytic carrier, Al₂O₃, not only increased the amount of 4-nitrophenol removed but also promoted mineralization and destroyed 4-nitrophenol, which was degraded to other simple organic substances or inorganic substances.