DEGRADATION OF 17Α-ETHINYLESTRADIOL IN WATER THROUGH HETEROGENEOUS PHOTOCATALYSIS

Wilton Silva Lopes, Maria Graziela Cristo de Oliveira Azevedo, Valderi Duarte Leite, José Tavares Sousa, Josué Silva Buriti

Abstract


The aim of the study was to investigate the degradation of 17α-ethynylestradiol in aqueous solution using a batch heterogeneous photocatalytic (HPC) reactor with ultraviolet (UV) light and TiO2 catalyst. In order to determine appropriate operating conditions, a 23 factorial experiment was conducted with initial substrate concentration of 15 or 30 mg.L-1, TiO2 concentration 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 initial substrate concentration of 15 or 30 mg.L-1, 0.02% TiO2 and 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 substrate was degraded when the initial concentration was 30 mg.L-1 (0.05% TiO2 and 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 TiO2 concentration. All degradations followed first-order kinetics. With 17α-ethynylestradiol at 15 mg.L-1, the half-life time (t½) 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 t½ values of which were 44.71 and 433.12 min.

Keywords


organic pollutant, reaction kinetic, water treatment



Revista Ambiente & Água. ISSN:1980-993X DOI:10.4136/1980-993X


Editoração:Apoio:Filiada à ABEC:
IPABHi CAPES CNPq ABEC