Background & aim: Antibiotics considered a major problem into the environment due to their accumulation feature and drug resistance. The aim of this study was optimization of ciprofloxacin antibiotic sonochemical degradation in US/PS/nZVI process by Central Composite Design method.

Methods: In this experimental study the effects of independent variables such as pH of solution, PS and nZVI concentrations on antibiotic degradation were investigated. After optimization, the synergistic degradation and the effect of detention time was determined. Antibiotic concentration was constant at 50 mg/L for all the samples. Antibiotic concentration was measured on the basis of COD reduction according to 5220 C of Standard Methods. For characterization of prepared nZVI particle, the transmission electron microscope image (TEM) was used.

Results: The results indicated the pH as a principal variable with the optimal value of 4.5 for this process. At initial concentration of 195 mg/L COD (equal 50 mg/L antibiotic), the optimal concentration of PS and nZVI were obtained at 1200 and 120 mg/L, respectively. At this condition removal efficiency of 57% was obtained after 60 min. At optimal conditions for US/PS/nZVI process the synergistic degradation was almost 42.55%. In investigating the effects of detention time, 94% of COD was removed after 180 min.

Conclusion: The results of this study confirmed the acceptable efficiency of US/PS/nZVI process in degradation of ciprofloxacin antibiotic.