Xinyu Yang,Bing Hou,Zongsheng Hu,Hao Jiang,Nan Li,Jingwen Pan,Lei Wang
Fluoride (F − ) pollution in surface water seriously endangers ecological safety. Cerium-based adsorbents have original advantages in adsorbing F − such as abundant oxygen vacancies and variable valence states. However, high cost and separation difficulty limit their application in fluoridated surface water treatment. This work synthesized bimetallic oxide adsorbents (FeCe@C) to enhance the efficacy of cerium-based adsorbents for F − removal and systematically examined how Fe(II) doping influenced fluoride removal efficiency. Results indicated that FeCe@C adsorbed F − better than the pure Ce-based adsorbent (Ce@C), with q max = 243.31 mg/g at 25℃, and reached adsorption equilibrium in merely five minutes, with significantly better adsorption performance than fluoride adsorbents reported in previous literature. F − adsorption process aligned with the Temkin (R 2 > 0.963), pseudo-second-order kinetic (R 2 > 0.999) and Elovich model (R 2 > 0.993), suggesting that the F − adsorption mechanism was governed by chemisorption-dominated heterogeneous surface reactions. Further results proved that the doping of iron exhibited a significant effect on the generation of Ce(III) active sites and oxygen vacancies in FeCe@C, which showed a positive correlation (R 2 = 0.87 and 0.98). And unlike other metal doping mechanisms, the doped Fe species promoted the formation of Ce(III) through redox reactions during the adsorption process, achieving the reverse conversion of Ce(IV) to Ce(Ⅲ), rather than directly participating in adsorption. Density functional theory (DFT) calculations demonstrated that iron doping effectively enhanced electron transfer and the interaction between F − and the adsorbent, resulting in a higher F − adsorption capacity. This study provides fundamental theory for enhanced fluoride removal and offers new ideas for elevating the efficacy of cerium-based adsorbents.
Metal–metal oxide nanostructures have drawn increasing research attention due to their unique properties enabled by strong interfacial interactions. However, the synthesis of metal–metal oxide nanocomposites with well-controlled architectures such as the core@shell structure remains challenging. Additionally, introducing plasmonic metal can endow the nanomaterials with photoresponsive functions, offering opportunities for optical modulation of catalytic properties. In this work, we designed and fabricated an over-reduced Au@CoOx-Co core–shell nanostructure using an improved seed growth process involving carbonyl precursors. The Au core serves as an in situ catalyst facilitating the over-reduced CoOx-Co shells, and the strong interfacial interaction introduces abundant oxygen vacancies (OVs) to provide reactive sites. Meanwhile, the Au core generates excitons under light irradiation, which can significantly enhance the activation of peroxymonosulfate (PMS) for degrading fluorine-containing pollutants. This design synergistically integrates structural design, photoelectronic regulation, and catalytic enhancement, demonstrating a promising application in the future.
The recalcitrance of fluorinated organic pollutants—featuring robust Csp²-F and Csp³-F bonds—poses critical challenges to aquatic ecosystems due to their extreme persistence and bioaccumulation. Whereas current destruction strategies suffer from high energy consumption and non-selective, here we present a solar-powered mineralization strategy utilizing cerium oxide/mesoporous silica (CeO 2 /mSiO 2 ) heterojunction photocatalysts for complete defluorination of organofluorine contaminants, including fluorinated e-waste, fluoro-antibiotics and perfluorinated surfactant. Under visible light irradiation, the optimized 5%CeO 2 /mSiO 2 achieved 91.1 ± 3.2% octafluorobiphenyl (OFB) and 97.7 ± 2.8% fleroxacin (FLE) degradations within 6 h. Notably, the ‘forever chemical’ perfluorooctanesulfonic acid (PFOS) can be effectively destructed, achieving a maximum of 25.9 ± 2.7% reduction in 5 days under sunshine, outperforming parallel experiments conducted without a catalyst (~0%). This process notably avoids the evolution of fluoride ions. Theoretical calculations reveal that the removal of C-F bonds by photogenerated hydroxyl radical is thermodynamically superior to hydroxyl-mediated defluorination. This work establishes an energy-efficient paradigm for eradicating “forever chemicals” without secondary pollution, advancing sustainable water remediation technologies.
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