Degradation of 17α-ethinylestradiol in water by heterogeneous photocatalysis

• Autor(a) principal: Lopes,Wilton Silva
• Data de Publicação: 2015
• Outros Autores: Azevedo,Maria Graziela Cristo de Oliveira, Leite,Valderi Duarte, Sousa,José Tavares, Buriti,Josué Silva
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Revista Ambiente & Água
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1980-993X2015000400728
• topic: Endocrine disrupters; reaction kinetic; water treatment

We investigated the degradation of 17α-ethynylestradiol in an aqueous solution using a batch heterogeneous photocatalytic (HPC) reactor with ultraviolet (UV) light and TiO2catalyst. In order to determine appropriate operating conditions, a 23factorial experiment was conducted with initial an substrate concentration of 15 or 30 mg L-1, TiO2concentration of 0.02 or 0.05%, pH of 5.0 or 9.0 and total reaction time 240 min. Degradation profiles and kinetic parameters were determined with an initial substrate concentration of 15 or 30 mg L-1, 0.02% TiO2and pH 7.0.With17α-ethynylestradiol at 15 mg L-1, degradation efficiency was 100% after 120 min independent of TiO2 concentration and pH. However, less than 50% of the substrate was degraded when the initial concentration was 30 mg L-1 (0.05% TiO2and pH 5.0). Initial substrate concentration was a limiting factor for HPC, although the reaction was also strongly influenced by TiO2 concentration and the interaction between initial substrate concentration and TiO2concentration. All degradations followed first-order kinetics. With 17α-ethynylestradiol at 15 mg L-1, the half-life time (t1/2) was 64.16 min and the rate constant was 0.108 min-1, while at 30 mg L-1, substrate degradation proceeded in two stages, the t1/2 values of which were 44.71 and 433.12 min.