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چکیده
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The objective of this study is to prepare a biochar catalyst loaded with manganese (IV) oxide to enhance the degradation of ciprofloxacin (CIP) antibiotic in the catalytic ozonation process (COP) and COP/peroxymonosulfate (PMS) process. XPS, FE-SEM, EDS, TEM, XRD, FTIR, and N2 adsorption-desorption isotherms were used to characterize the β-MnO2/biochar catalyst. According to N2 adsorption-desorption isotherms, activation at 800 ℃ in 120 minutes with a weight ratio of 1:1 (KOH/BC) fabricates biochar with a high specific surface area (1149 m2.gr-1). The results of the characterization techniques confirmed the successful loading of β-MnO2 nanorods on the porous biochar substrate. D-optimal method to save time and cost of experiments. Based on the results, the optimal conditions in the COP were obtained with the catalyst amount of 0.15 g L-1, initial CIP concentration of 20 ppm, input ozone flow rate of 1.25 mg min-1, and pH=7. The degradation efficiencies of CIP in 30 minutes for COP and sole ozonation process (SOP) were 98.7 and 48.8%, respectively. PMS was used, to improve the degradation rate and mineralization efficiency of the processes. The results showed that the degradation rate increased from 0.120 min-1 to 0.219 min-1 in the presence of PMS. Measuring the COD showed the high performance of the COP/PMS process compared to COP and SOP with a mineralization efficiency of 78, 56.4, and 17.1% within 30 min, respectively. The reactive oxygen species involved in the mentioned processes were identified by inorganic and organic scavengers. According to the results, the •OH had the largest contribution to these processes. The circulating fluidized bed reactor showed better performance compared to the semi-continuous reactor due to better mixing conditions. The β-MnO2/BC1-800-120 catalyst could maintain its catalytic activity after three cycles of use in the COP, which shows its high stability.
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