Products and Mechanism Analysis of Ciprofloxacin Degradation inWater by UV activated Persulfate

GUO Hongguang, LIU Yang, KE Tingling, ZHAO Chengwei, TANG Weihong

Abstract

Long term ecological and physiological toxicity caused by the residuals of fluoroquinolones (FQs) in the aquatic environment has raised much attention. Ciprofloxacin as a typical FQs was degraded by UV activated persulfate,which was a new advanced oxidation technology. The degradation products were characterized using qualitative and quantitative methods,and the detailed degradation mechanism and pathways of ciprofloxacin by UV/persulfate were proposed by using the analysis results of quantum chemistry and mass spectra. The results revealed that the optima condition for CIP degradation was pH 9.0. After a 30 min reaction,13 intermediates were identified in the solutions,including alcohols,phenols,ketones and amides. The concentrations of several intermediates exhibited an up and down trend. Oxidations mainly occurred at the C F bond and carboxylic acid on quinolone group,as well as piperazine group. The degradation of CIP by UV/PS mainly included four pathways,and a series of defluorination,photolysis,substitution,addition and deamination were observed,leading to the final open ring reaction of target compound.

 

 

Keywords: fluoroquinolones,  persulfate,  ultraviolet activation,  mechanism,  products


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