Study On Degradation Of Ketoprofen By Peroxymonosulfate Activated By Ferrous Ions

Ketoprofen (KTP),1-(3-phenoxy) phenylpropionic acid, as a high efficient non-steroidal anti-inflammatory drug has been used for curing rheumatoid arthritis, rheumatoid arthritis, myositis and osteoarthritis, etc. However, people who ingested KTP for a long-term may have a side-effect such as the intestinal complications. In China, KTP has been identified and detected in aqueous. The degradation of KTP using traditional activated sludge process couldn’t achieve a available result, and although by using film processing method can achieve a certain effect, the cost was much more higher. Comparing with the biological and physical methods, the advanced oxidation more suitable for the organic pollutants degradation. Therefore, the advanced oxidation technology has a certain advantage in terms of practical, Fe2+ -activated peroxymonosulfate (Fe2+/PMS) can quickly produce sulfate radicals (SO4-) which has the same redox potential as hydroxyl radical (HO), and it was not only suitablely in wide pH value but also easy to operate. In a word, SO4- was a better choice for the degradation of KTP.This study used SO4- which was produced by Fe2+ -activated peroxymonosulfate (Fe2+/PMS) as the oxidizer to oxidize KTP in aqueous. The degradation of KTP under different pH values, temperatures, concentrations of Fe2+ and the sequential additions of Fe2+ was studied in order to find out the optimal conditions for degrading KTP. The results demonstrated that SO4- and HO-were detected in the degradation system via using ethanol and tertiary butanol as molecular probes, and SO4- played a primary role at acidic and neutral conditions, while HO·was the main oxidizing specie at alkalinity condition. The results also showed that the highest KTP decomposition 66.8%, occurred when the pH value is 3 with temperature 45℃ and the ratio of Fe2+/PMS/KTP is 20/15/1. The sequential addition of Fe2+ appeared a persistently production of sulfate radicals that was desirable of degrading KTP. Fe2+ -activated peroxymonosulfate (Fe2+/PMS) had a good result in KTP removal.The optimal conditions for using Fe2+-activated peroxymonosulfate to degrade KTP were obtained. The chelating agents such as citric acid, EDTA, tartaric acid, oxalic acid, potassium pyrophosphate played a key role in promoting the degradation of KTP. The results demonstrated that the highest KTP decomposition occurred when the concentration ratio between citric acid and Fe2+, EDTA and Fe2+, tartaric acid and Fe2+, oxalic acid and Fe2+, potassium pyrophosphate and Fe2+were 0.01/1,1/1,0.05/1,0.01/1, 0.05/1, and the KTP degradation rate reached to 83.2%,87.4%,77.4%,73.3% and 77.4% apart. We also studied the optimal pH value for degrading KTP in citric acid, EDTA, tartaric acid systems apart. The results demonstrated the highest KTP degradation rate occurred when the pH value is 9, this result may attribute to the best complexing effect showed when the pH value is 9.In this paper, the effects of pH、natural water composition (H2PO4-、HCO3、Cl-、 NO2-、humic acid) on the degradation of KTP were investigated under which the pH value is 3 and the concentration ratio of Fe2+, PMS and KTP was 20:15:1. Low concentration of H2PO4-, HCO3- and HA had positive effects on the degradation of KTP, while high concentration of them. Cl- and NO2- inhibited inhibited the degradation of KTP, too. The degradation products of KTP were identified by HPLC/MS/MS, which werel-(3-Benzoyl-phenyl)-ethanone,3-Ethyl-phenyl)-phenyl-methanone,[3-(1-Hydroxy-ethyl)-phenyl]-phenyl-methanone,(3-Ethyl-phenyl)-phenyl-methanone,[3-(1-Hydroxy-et hyl)-phenyl]-phenyl-methanone,2-[3-(2-Hydroxy-benzoyl)-phenyl]-propionic acid and [3-(1-Hydroxy-ethyl)-phenyl]-(2-hydroxy-phenyl)-methanone, at last, the possible pathways were proposed.