Preliminary study of ciprofloxacin (cip) removal by potassium ferrate(VI)

Abstract

Ciprofloxacin was identified among the top 10 of high priority pharmaceuticals detected in aquatic environment. Potassium ferrate(VI) is a strong oxidant which possesses very high redox potential and has been widely studied in water disinfection and removing organic and inorganic pollutants. There has been one published work to detail the removal of phosphorus as well as micro-pollutants including ciprofloxacin by ferrate in wastewater treatment. However, developing a simple ciprofloxacin detection method and study of feasibility of its treatment by ferrate was the objective of this work. Solid phase extraction (SPE) and UV/vis spectrophotometer at 280nm was employed to analyse CIP. A series of jar test experiments was carried out to evaluate the ferrate performance for CIP reduction. Results demonstrated that a SPE coupled with simple UV/vis spectrophotometric method can detect CIP with detection limit of 10μg/L for model wastewater samples. Ferrate can remove at least 60% of CIP from model wastewater even at very low ferrate doses (<0.3mg/L). Besides, with increasing in ferrate dose up to 1mg/L as Fe, the removal efficiency of CIP was higher than 80%. However, increasing ferrate dose further did not show significant increasing in CIP removal. Initial pH of CIP model wastewater samples has no obvious influence on CIP removal, while final solution pH (adjusted and after dosing ferrate) affected the performance of ferrate treatment significantly. CIP removal efficiency by ferrate decreased significantly if final pH of the waste water solution was greater than CIP’s pKa (i.e. pH>8).