Fabrication of a highly efficien self-assembled “Dual-Carrier” catalyst and its application in emerging contaminant degradation systems: performance, mechanisms, and ecotoxicity

This study introduces an innovative “assembly-pyrolysis-reassembly” strategy utilizing phenolic resin-derived carbon spheres (Prc) as substrates. By sequentially anchoring Co-Mn₃O₄ and Mil-53(Fe) nanomaterials onto the Prc carrier, the strategy simultaneously enables Mil-53(Fe) to function as a nanoscale carrier for Co-Mn₃O₄, ultimately synthesizing the high-performance catalyst Prc@Co-Mn₃O₄/Mil-53(Fe). The catalyst exhibits exceptional peroxymonosulfate (PMS) activation across a broad pH range, achieving 100 % degradation efficiency for tetracycline (TC, 20 mg/L) within 15 min under optimal conditions (0.3 g/L catalyst, 0.3 mM PMS, pH 7.0, 25 °C), with a maximum degradation rate constant (k) of 0.1511 min⁻¹. Synchrotron radiation analyses and density functional theory (DFT) calculations demonstrate that interfacial active sites formed between the Mil-53(Fe) nanocarriers and Co-Mn₃O₄ on the porous Prc substrate significantly enhance catalytic performance. Using TC as a model pollutant, the study reveals a non-radical-dominated degradation mechanism, primarily driven by singlet oxygen (¹O₂). Electron paramagnetic resonance (EPR) and quenching experiments validated the types and relative contributions of reactive oxygen species (ROS). High-performance liquid chromatography-mass spectrometry (HPLC-MS) identified intermediate products, enabling the proposal of plausible degradation pathways. The Toxicity Estimation Software Tool (T.E.S.T.) program further assessed the ecotoxicity of intermediates, predicting their environmental impacts. In summary, the Prc@Co-Mn₃O₄/Mil-53(Fe) catalyst, synthesized via the “assembly-pyrolysis-reassembly” strategy, features a unique “inorganic carrier-metal nanocarrier” dual architecture.