Optimization removal of ciprofloxacin with photo fenton process using Response Surface

Pharmaceutical compounds in drinking water resources, in addition to the threat for environmental health, spread of bacterial resistance in aqueous environments. In this study, ciprofloxacin removal by photo Fenton oxidation process and optimization of the removal conditions was evaluated using response surface methodology.
In this experimental study, in optimum pH=3, the effect of initial concentration of ciprofloxacin (50-250 mg/L), contact time (10-60 min), the amount of iron nitrate (0.1-0.5 mM) and the amount of H2O2 (1-12 mM), mole ratio of reactants of the antibiotic removal per central composite design by Design Expert software was evaluated. For statistical analysis of data, ANOVA test and P-value was used. Ciprofloxacin concentrations were measured using HPLC.
The results showed that removal efficiency by increasing concentrations of ciprofloxacin decreased and with increasing the amount of ferric nitrate, hydrogen peroxide and exposure time increased. In central composite design method, maximum removal efficiency (85.8%) in pH= 3, was obtained with concentration 88.5 mg/l ciprofloxacin, 0.35 mM iron nitrate, 11.54 mM H2O2 and exposure time of 57 min and molar ratio of H2O2 to Fe (III) were [11.54]/ [0.35]. Investigation revealed kinetics terms showed that the removal of ciprofloxacin with (R2= 0.953) was followed second order rate.
The results obtained from this research indicated that photo Fenton- like process is effective way to remove ciprofloxacin from wastewater and with optimization affecting factors; this method can be used for wastewater treatment with antibiotic.