Degradation of carbamazepine and toxicity evaluation using the UV/persulfate process in aqueous solution

Abstract BACKGROUND Using persulfate in an advanced oxidation process to degrade organic pollutants has gained more attention in recent years. In this study, an ultraviolet activated persulfate oxidation process used to degrade carbamazepine ( CBZ ) in aqueous solution was investigated. The effect of persulfate dosage, pH , inorganic anions and humic acid on the degradation of CBZ was determined. In addition, the transformation intermediates produced during the process were identified using gas chromatograph–mass spectrometry ( GC‐MS ). Photobacteria were used to evaluate the toxicity of the transformation products . RESULTS The results showed that the degradation efficiency increased with increasing persulfate dosage but decreased with the addition of Cl − and NO 3 − . Acidic conditions were more suitable for the treatment. Sulfate radical was identified to be the predominant radical in the oxidation process when the solution pH was not adjusted. Several compounds including 10, 11‐epoxycarbamazepine, acridine‐9‐carbaldehyde, acridine and other low molecular compounds were identified. A possible degradation pathway was also proposed. Acute toxicity tests indicated that the inhibition ratio decreased from 100% to 65% in 60 min, illustrating that the toxicity significantly decreased with the degradation of CBZ . CONCLUSION Considering all of the factors, UV /persulfate may be a promising option for CBZ treatment. © 2014 Society of Chemical Industry