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Resumo(s)
Perovskites of the (La,Ba)(Fe,Ti)O3
family were prepared, characterized, and utilized as
heterogeneous photocatalysts, activated by natural sunlight, for environmental remediation of Acid
Orange 7 (AO7) aqueous solutions. Catalysts were prepared by the ceramic (CM) and the complex
polymerization (CP) methods and characterized by XRD, SEM, EDS, and band gap energy. It was
found that catalytic properties depend on the synthesis method and annealing conditions. In the
photocatalytic assays with sunlight, different AO7 initial concentrations and perovskite amounts
were tested. During photocatalytic assays, AO7 and degradation products concentrations were
followed by HPLC. Only photocatalysis with BaFeO3
-CM and BaTiO3
-CP presented AO7 removals
higher than that observed for photolysis. However, photolysis leads to the formation of almost
exclusively amino-naphthol and sulfanilic acid, whereas some of the perovskites utilized form lesstoxic compounds as degradation products, such as carboxylic acids (CA). Partial substitution of Ba by
La in BaTiO3
-CM does not produce any change in the photocatalytic properties, but the replacement
of Ti by Fe in the La0.1Ba0.9TiO3
leads to reduced AO7 removal rate, but with the formation of CAs.
The best AO7 removal (92%) was obtained with BaFeO3
-CM (750 mg L−1
), after 4 h of photocatalytic
degradation with solar radiation
Descrição
Palavras-chave
Perovskites (La,Ba)(Fe,Ti)O3 Photocatalysis Sunlight Ceramic method Complex polymerization