Enhanced TC degradation by persulfate activation with carbon-coated CuFe2O4: The radical and non-radical co-dominant mechanism, DFT calculations and toxicity evaluation

Facing the constraints of critical agglomeration and poor reusability of CuFe2O4 in catalytic applications, the feasibility of synthesizing a composite catalyst using carbon coating technology for efficient TC removal with enhanced PDS activity was investigated. The composite catalyst (CuFe2O4@C) can stimulate both radical (SO4•- and HO•) and non-radical (1O2) pathways to dominate the catalytic reaction for removing 95.7% of the TC in 60 min. Meanwhile, the defective structure of the external carbon layer protected the internal CuFe2O4 from excessive oxidation, allowing the CuFe2O4@C to maintain over 90% TC removal after 5 cycles with less interference from inorganic anions, demonstrating significant catalytic performance and satisfactory reusability. Finally, the DFT calculations and TEST evaluation were performed to discuss the structural properties of TC and its toxicity assessment during the whole degradation process, while three possible degradation pathways were proposed. Significantly, the carbon-coated composite catalysts of potential universal applicability for multi-pathway PDS activation offered an attractive new strategy for the effective degradation of antibiotic wastewater. Tetracycline (TC) has been identified as one of the most widely used antibiotics in the world with irreversible effects on humans and the environment if not treated thoroughly. The composite catalysts synthesized with carbon coated technology allowed for the efficient removal of TC from the aqueous environment in a multi-path manner and maintained a high level of reusability. The eco-friendliness of the whole TC removal process was further demonstrated by DFT calculations and TEST evaluation.