A series of CoFe-LDHs@MoS 2 -x (x = 0.1, 0.2 and 0.5) samples were successfully synthesized to activate peroxymonosulfate (PMS) for tetracycline (TC) removal. With the introduction of MoS 2 could promote the catalytic performance via accelerating the Fe 2+ /Fe 3+ and Co 2+ /Co 3+ cycle. About 98.8 % of TC could be removed over 12 min under a neutral condition in the CoFe-LDHs@MoS 2 -0.2/PMS system, which was 4.4 times higher than that of CoFe-LDHs/PMS system. The main reactive oxygen species (ROS) in CoFe-LDHs@MoS 2 -0.2/PMS system were also explored by using quenching and free radical capture experiments. The singlet oxygen ( 1 O 2 ) played a major role for the TC removal. Besides, the decomposition pathways of TC were deduced by UPLC-QTOF/MS, and the stability of catalysts had also been studied. This work provided theoretical and experimental basis for designing and preparation more effective heterogeneous catalysts for PMS activation .
The utilization of the photo catalytic activation of permonosulfate (PMS) for the combined breakdown of pollutants has become a focal point in research. Layered double hydroxides (LDHs) have a unique layered structure which is conducive to the adsorption and diffusion of reactants, and can provide more active sites for photocatalytic reactions. The anions between the layers can be exchanged with a variety of substances so that specific catalytically active species can be introduced as needed. LDHs themselves have certain catalytic activity, which can produce synergistic catalysis between LDHs and the supported photocatalytic active substances, and further improve the degradation effect of antibiotics. In actual wastewater treatment, LDHs as a catalyst carrier have a good application prospect. However, the poor activation effect is attributed to the low separation efficiency of catalyst carriers and insufficient active sites. In this study, a dual active site system consisting of Co and Fe, known as CoFe-LDHs@MoS2, was developed as a catalyst to facilitate the synergistic degradation of norfloxacin (NOF) by PMS under visible light. The findings demonstrate that the material possesses an effective capacity for the synergistic degradation of NOF. A comprehensive investigation was conducted to assess the impact of different catalysts, PMS dosage, degradation systems (Vis, PMS, or Vis PMS), catalyst dosage, NOF concentration, pH, and cycle times on the degradation performance. The active free radicals, degradation pathways, and intermediate toxicity were elucidated through capture experiments, Electron Paramagnetic Resonance Spectrometer (ESR) analysis, a liquid mass spectrometry (LC-MS) toxicity assessment, and theoretical calculations. This research offers a novel approach for designing catalysts with exposed high activity sites for the effective removal of NOF from environmental water.
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