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The increasing use of fluoroquinolone antibiotics, which are found in various environmental media, is a constant threat to ecological safety and human health. In this paper, SrFeO3@MoS2 heterogeneous catalyst was prepared to activate peroxymonosulfate (PMS) for the degradation of levofloxacin (LVO). The characteristics of SrFeO3@MoS2 samples were studied and the optimum conditions for the removal of LVO by SrFeO3@MoS2/PMS system were investigated. The removal of LVO by the SrFeO3@MoS2-0.3/PMS system could reach 96.06% within 20 min of reaction. The effect of inorganic anions (SO42−, Cl−, NO3− and H2PO4−) commonly found in actual water bodies on catalytic reaction was explored. The reusability investigation revealed that the catalyst could still remove 88.06% of LVO within 20 min after four cycles. Moreover, SO4•−, •OH and 1O2 were identified by Electron Paramagnetic Resonance (EPR) tests and scavenger experiments, where the SO4•− and •OH were dominant reactive species. Combining with the XPS characterisation, the activation mechanism of SrFeO3@MoS2-0.3/PMS was proposed, and the oxygen vacancies and transition metals on the sample surface were active sites of PMS activation. Furthermore, the possible degradation pathways of LVO were well-established based on the detected intermediates. [ABSTRACT FROM AUTHOR]

[Display omitted] • CeO 2 -loaded spinel catalysts exhibited significant morphology-dependent catalytic activity. • Nanocubes CeO 2 -loaded spinel (CFOC-C) composite displayed superior peroxymonosulfate activation performance. • Increased radicals could be generated via stronger peroxymonosulfate adsorption from the CFOC-C catalyst. • The Ce sites in the crystal phase of CeO 2 (1 0 0) had a preferable electron migration capacity towards the PMS molecule. The composite catalysts with different morphologies (nanorods, nanocubes, nano-polyhedra and nanosphere) of ceria as loadings are prepared by using spinel as the carrier to investigate the crystal plane effect of ceria on the formation of oxygen vacancies in the catalyst and the activation efficiency of peroxymonosulfate (PMS). The results show that the CeO 2 nanocubic-based composite (CFOC-C) with more (1 0 0) crystal phase has superior catalytic performance in each individual condition, providing rapid activation of PMS and pollutant degradation. Through characterizations, the largest oxygen vacancy concentration is observed on the CFOC-C surface and the strongest reactive oxygen detection signal is obtained in the CFOC-C/PMS system. Moreover, the more active (1 0 0) crystal phase on the CeO 2 surface promotes the electron delocalization at Ce sites, accelerating the adsorption of PMS molecules and the cleavage of O-O bonds, subsequently generating more active species. With levofloxacin as the target, the main degradation intermediates and the degradation pathways in the CFOC-C/PMS system are analyzed in detail. The toxicity estimation results suggest that the toxicity of the degradation products decreases progressively with the reaction. [ABSTRACT FROM AUTHOR]

Advanced strategies for enhancing catalytic performance of catalysts include multi-metal active site exposure, vacancy growth and electronic structure optimization. Here, carbon nanotube-loaded CoSe 2 /FeSe 2 catalysts (Co/Fe-CNT) with multiphase boundaries and embedded selenium vacancies (V Se) were prepared using a one-step hydrothermal method. The catalysts feature unique electronic structures and abundant active sites, and were found to exhibit unexpectedly high activity and stability in photocatalytic mediated sulphate radical (SR-photo) system, with impressive oxidation capacity for complex matrix polluted water. The spontaneously formed internal electric field strongly promoted charge transport and significantly enhanced the photocatalytic property. The V Se formed at the heterogeneous interface could modulate the surface electronic structure and accelerate the redox cycling of transition metals, thereby accelerating the production of reactive oxygen species and boosting the efficiency of contaminant degradation. This work provides guidance for the design of high-performance catalysts for V Se engineering and expands their potential for application in wastewater purification. [Display omitted] • A nanorods embedded with crystal-like Co/Fe-CNT containing heterostructure and selenium vacancies (VSe) was prepared. • 1Co/1Fe-CNT with heterojunction interface exhibited excellent photocatalytic PMS activation for pollutants degradation. • The built-in electric field in Co/Fe-CNT boosted charge separation confirmed by DFT calculation. • The introduction of VSe promoted the redox cycle of transition metals and enhanced the adsorption of PMS on active sites. [ABSTRACT FROM AUTHOR]

In recent years, many efforts have been made to modulate the interaction between carriers and nanoparticles under the integrity of the active site structure. Herein, SrFeO 3 @CoSe 2 nanocomposite was fabricated by loading CoSe 2 onto SrFeO 3 particles with a perovskite structure in the form of an encapsulation. The optimized SFO@CS-0.3 catalyst exhibited high catalytic activity in photo-peroxymonosulfate-based reaction and the catalyst was structurally stable over a wide temperature range. Characterization and theoretical results demonstrated that the charge in the SrFeO 3 was transferred from Fe to Co cation of the CoSe 2 via the interfacial oxygen atom. Moreover, the newly established oxygen-metal structure (Fe-O v -Co) acted as a catalytic site, accelerating the cleavage of the peroxymonosulfate bond to generate radicals, which were desorbed into solution to attack the contaminant. Simultaneously, the heterojunction constructed by the catalyst underwent internal electron transfer under visible light, creating a field in which multiple reactive oxygen species co-oxidized organic contaminant. [Display omitted] • A novel encapsulated structural SFO@CS catalyst was constructed to enhance PMS activation. • SFO@CS-0.3 exhibited excellent performance in the activation of PMS for recalcitrant pollutant elimination. • SO 4 •- and •OH played dominating roles in catalyst/PMS/Vis-light system. • The oxygen-metal structure (Fe-O v -Co) acted as newly site to facilitate the cleavage of the O-O bond in PMS. • The interfacial charge transfer took place from the Fe-d and O-p orbitals of SrFeO 3 to the Co-d orbital of CoSe 2. [ABSTRACT FROM AUTHOR]

[Display omitted] • MoS 2 embedded manganese ferrite doped perovskite nanocomposites were synthesized. • Accelerated decomposition of PMS via SMM nanocomposites under visible light irradiation. • The SMM-3 nanocomposite showed excellent catalytic activity and applicability for LVF degradation in real water matrix. • MoS 2 embedded structure contributed to efficient electron transfer of SMM. • Radicals (SO 4 •-, HO• and O 2 •-) and non-radical (1O 2) processes are involved in the degradation reaction. The nanocomposite of MoS 2 embedded manganese ferrite doped perovskite (SrCoO 3 /MnFe 2 O 4 /MoS 2 , abbreviated as SMM) was successfully synthesized for peroxymonosulfate (PMS) activation under visible-light. It was optimized that the SMM-3 (mass ratio of MoS 2 modified nanocomposite was 0.3) exhibited excellent catalytic performance to activate PMS for levofloxacin (LVF) degradation, with the degradation efficiency of 95.1% in 20 min. Besides, SMM-3 was able to efficiently degrade LVF under real water matrix. The quenching experiments and electron paramagnetic resonance (EPR) analysis revealed that SO 4 •- and HO• played a dominant role in reaction. Due to the photocatalytic property of nanocomposites, the visible light could excite electrons to react with oxygen and form O 2 •-, which further reacted with HO• to produce 1O 2. In the reaction process, the rapid redox cycle of metal ions (including Co, Mn, Fe and Mo) boosted the activation of PMS and promoted the degradation of LVF in a short time. The Density functional theory (DFT) calculation and LC-MS/MS further revealed that oxidation of piperazine ring, decarboxylation and defluorination processes were the main LVF degradation pathways. Finally, the toxicity analysis based on Toxicity Estimation Software Tool (T.E.S.T) verified the ecological risks of transformation residues. [ABSTRACT FROM AUTHOR]

[Display omitted] • Stable encapsulated SC@MoS 2 crystal was facilely fabricated by hydrothermal method. • MoS 2 coating facilitated electron transfer and rapidly activated PMS to generate reactive oxygen species. • Oxygen defects and transition metals act as active sites for the activation of PMS. • Feasibility of SC@MoS 2 /PMS system was proved by organic pollutants degradation and reusability. Perovskite oxides and molybdenum sulfide (MoS 2) are both promising catalysts for advanced oxidation processes in environmental pollutant degradation. Herein, a core-shell structure of MoS 2 encapsulating Sr-Co perovskite microcrystalline (SC@MoS 2) was used to activate peroxymonosulfate (PMS) for degradation of organics. Levofloxacin (LVF) degradation by SC@MoS 2 /PMS system was improved obviously, and 0.2-SC@MoS 2 exhibited the optimized activation for PMS with best LVF degradation performance (97%) within 15 min. In the 0.2-SC@MoS 2 /PMS system, the dosage of catalyst was the key determinant of LVF degradation. Simultaneously, 0.2-SC@MoS 2 achieved outstanding reusability and good degradation capacity of different contaminants. The encapsulation of molybdenum disulfide layer facilitated electron transfer between PMS and core-shell structure. According to the EPR analysis and quenching experiments, both radicals (SO 4 − and OH), and nonradical (1O 2) were involved in the degradation of LVF. Under visible light irradiation, O 2 − participated in the reaction and enhanced LVF degradation efficiency, because the valence band and conduction band of components are different. Furthermore, the density functional theory (DFT) calculation, intermediates determination and Toxicity Estimation Software Tool (T.E.S.T) analysis provided meaningful support in the degradation pathways and ecological risks of LVF residues. [ABSTRACT FROM AUTHOR]

[Display omitted] • SrTiO 3 /CoFe 2 O 4 /rGO ternary nanocomposites were synthesized by calcination-hydrothermal method. • Levofloxacin was efficiently degraded by free radicals (SO 4 −, OH) and non-free radical (1O 2). • SCG-1 nanocomposites showed excellent PMS catalytic activity and stability of reaction. • The rGO loading accelerated the activation of PMS by SrTiO 3 /CoFe 2 O 4 /rGO nanocomposites. In this study, ternary magnetic nanocomposites (SrTiO 3 /CoFe 2 O 4 /rGO, SCG) doped with cobalt ferrite and loaded with rGO were successfully synthesized, and utilized to rapidly activate PMS to degrade LVF. After evaluating the efficacy of samples with different loading loads, SCG-1 (1 % wt rGO loading) was selected for further testing due to its optimal catalytic activity (degradation efficiency reached 87.4 % in 5 min). Quench experiments and electron paramagnetic resonance (EPR) analysis showed that SO 4 −, 1O 2 , OH were the main active substance involved in LVF degradation. Based on the redox cycle of Co and Fe ions and the platform provided by perovskite and rGO, the reaction can be carried out quickly. The vulnerable sites and possible degradation pathways of LVF were further analyzed by density functional theory (DFT) calculation and LC-MS/MS analysis, and the developmental toxicity and ecological risk of intermediate products were determined based on toxicity assessment software (T.E.S.T). This study provided a new vision for realizing rapid antibiotic degradation in water environments and provided theoretical support for the subsequent research on novel nanomaterials. [ABSTRACT FROM AUTHOR]