DEGRADATION OF 17Α-ETHINYLESTRADIOL IN WATER THROUGH HETEROGENEOUS PHOTOCATALYSIS
Keywords:
organic pollutant, reaction kinetic, water treatment
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.
Published
20/10/2015
Issue
Section
Papers
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