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The degradation efficiency and mechanism of meclofenamic acid in aqueous solution by UV irradiation

Abstract: The photodegradation of meclofenamic acid (MCFA) was investigated using UV irradiation process. Parameters affecting the photodegradation process such as dissolved oxygen, reaction temperature, solution pH, initial MCFA concentration, humic acid, cations and anions were carried out. The intermediate products were identified by HPLC-MS analysis, and a tentative photodegradation pathway of MCFA was proposed. Results show that the photodegradation of MCFA can be modeled by the first-order kinetics. The photodegradation efficiency increases with the decreased concentration of humic acid or the decreased initial MCFA concentration, while the reaction temperature and the inorganic ions have no significant effect on the MCFA removal. It has found that the optimal initial solution pH for MCFA degradation is about 7.0. Finally, the HPLC-MS results reveal that the Cl atom in the MCFA molecule would form Cl–, followed by dechlorination, hydroxylation and cyclization of pentacyclic compounds.