Degradation of Chlorogenic Acid by Magnetic Field Coupled Fe-C Activated Persulfate Process
Chlorogenic acid (CGA), a key component of the anti-COVID drug Lianhua Qingwen, is recalcitrant to biodegradation and tends to bioaccumulate, posing risks to aquatic ecosystems. Conventional water treatment methods are inadequate for its removal. This study investigated the degradation of CGA using a magnetic field coupled Fe-C activated persulfate (MF/Fe-C/PS) advanced oxidation process. The degradation efficiencies of Fe-C, PS, Fe-C/PS, and MF/Fe-C/PS systems were compared, and the dominant reactive species and their contributions were identified. The effects of initial pH, persulfate (PS) concentration, Fe-C dosage, and inorganic anions on degradation kinetics were examined, along with the degradation pathway and disinfection byproduct (DBP) formation potential. Results showed that MF/Fe-C/PS achieved 99% degradation of CGA within 60 min under optimal conditions: pH=3, PS concentration 1.5 mmol·L−1, and Fe-C dosage 0.4 g·L−1. Coexisting Cl−, Br−, and I− inhibited CGA oxidation to varying degrees, as did natural organic matter (FA and BAS). The reactive species SO4−·, ·OH, and 1O2 contributed 41.6%, 30.5%, and 27.9%, respectively. Degradation mechanisms included hydrolysis, dehydroxylation, decarboxylation, and benzene ring cleavage. Pre-oxidation by MF/Fe-C/PS significantly reduced the DBP formation potential during subsequent chlorination/chloramination. Energy per order (EE/O) analysis indicated favorable economic efficiency.