Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8874413 | Water Research | 2018 | 11 Pages |
Abstract
The presence of antibiotics in water bodies has received increasing attention since they are continuously introduced and detected in the environment and may cause unpredictable environmental hazards and risks. The photocatalytic degradation of sulfamethoxazole (SMX) by ZnO in the presence of fluoride ions (F-ZnO) was evaluated. The effects of operating parameters on the efficiency of SMX removal were investigated by using response surface methodology (RSM). Under the optimum condition, i.e. photocatalyst dosageâ¯=â¯1.48â¯g/L, pH 4.7, airflow rateâ¯=â¯2.5â¯L/min and the concentration of fluoride ionsâ¯=â¯2.505â¯mM, about 97% SMX removal was achieved by F-ZnO after 30â¯min of reaction. The mechanism of reactions, COD removal efficiency and reaction kinetics were also investigated under optimum operating conditions. In addition, about 85% COD reduction was obtained after 90â¯min photocatalytic reaction. The pseudo-first-order kinetics rate constants for the photodegradation of SMX were found to be 0.099, 0.058 and 0.048 minâ1 by F-ZnO, ZnO and TiO2 (P25), respectively. The figure-of-merit electrical energy per order (EEO) was used for estimating the electrical energy efficiency, which was shown to be considerably lower than the energy consumption for the reported research on removal of SMX by photocatalytic degradation under UV irradiation. Toxicity assays were conducted by measuring the inhibition percentage (PI) towards E. coli bacteria strain and by agar well diffusion method. The results showed that after 30â¯min of reaction, the toxicity of the treated solutions by all photocatalysts fell within the non-toxic range; however, the reduction in toxicity by F-ZnO was faster than those by ZnO and P25. Despite the positive effects of surface fluorination of ZnO on the SMX and COD removal and reaction kinetics, its lower stability compared to ZnO and P25 in the repeated experiments gave rise to some doubts about its performance from a practical point of view.
Keywords
Related Topics
Physical Sciences and Engineering
Earth and Planetary Sciences
Earth-Surface Processes
Authors
Amir Mirzaei, Laleh Yerushalmi, Zhi Chen, Fariborz Haghighat, Jianbo Guo,