Ibuprofen degradation by a synergism of facet-controlled MIL-88B(Fe) and persulfate under simulated visible light.

The photocatalysis/persulfate (PS) hybrid system has proven to be a promising method for degrading organic pollutants from aqueous solutions. In this study, three MIL-88B(Fe) iron-based metal-organic framework (MOF) phases with different facet content were prepared and used both as photocatalysts and catalysts for PS activation to remove ibuprofen (IBP). The results showed that there was a close correlation between the exposed facets and the catalytic activity. MIL-88B(Fe)-1 (M88B1) with exposed {100} facets and proportionally more {101} facets showed the best catalytic activity. The optimum PS dosage used in this study was 60 mg/L. The presence of Cl-, SO42-, and NO3- all inhibited the degradation of IBP. X-ray photoelectron spectroscopy (XPS) showed that M88B1 possessed more Fe2+ than the other two MIL-88B(Fe) MOF phases, making it easier to generate active radicals through PS activation. The UV-vis diffuse reflectance spectra (DRS), photoluminescence (PL), and electrochemical analysis indicated that M88B1 possessed the highest light absorption, most active sites, and fastest charge transfer ability. Radical scavenging and electron spin resonance (ESR) experiments demonstrated that SO4-•, •OH, O2-•, and 1O2 species participated in the IBP degradation process. Furthermore, density functional theory (DFT) calculations were performed to identify the crystallographic facets, band structure, and total density of states of MIL-88B(Fe) to further confirm the mechanism of MIL-88B(Fe) as a photocatalyst and a PS activator. This work provides new insights into the synergism between photocatalysis and persulfate activation by facet-controlled MOFs for environmental remediation.

Liu N ，Wu J ，Fei F ，Lei J ，Shi W ，Quan G ，Zeng S ，Zhang X ，Tang L ... -  《-》

Visible-light-assisted persulfate activation by SnS(2)/MIL-88B(Fe) Z-scheme heterojunction for enhanced degradation of ibuprofen.

Herein, a highly efficient Z-scheme SnS2/MIL-88B (Fe) (SnSFe) heterojunction was successfully synthesized to use both as photocatalysts and persulfate (PS) activator for ibuprofen (IBP) degradation. Flower-liked SnS2 was uniformly loaded on MIL-88B (Fe), and SnSFe retained the original polyhedral morphology of MIL-88B (Fe). The highest removal of IBP was achieved in the presence of SnSFe with 0.5% SnS2(SnSFe0.5). Characteristic results and density functional theory calculations demonstrated that the enhanced degradation of IBP was due to the difference in Fermi energy levels of SnS2 and MIL-88B (Fe) leading to electrons transferred from SnS2 to MIL-88B (Fe), and SnO bond was formed in SnSFe. , OH and O2- were the main active species in SnSFe0.5/PS/visible light system. Z-scheme heterojunction of SnSFe was constructed to propose the degradation mechanism. This research revealed that the synergism of photocatalysis and PS activation using SnS2/Fe-based MOFs composites possessed great potentials in wastewater remediation.

Liu N ，Fei F ，Dai W ，Lei J ，Bi F ，Wang B ，Quan G ，Zhang X ，Tang L ... -  《-》

Boron nitride nanosheets decorated MIL-53(Fe) for efficient synergistic ibuprofen photocatalytic degradation by persulfate activation.

In this study, based on one-step hydrothermal method, boron nitride nanosheets (BNNs) and MIL-53(Fe) composites (BNFe-X) were successfully prepared and the catalytic performance of BNFe-X on persulfate (PS) activation for ibuprofen (IBP) photodegradation was investigated. The introduction of BNNs changed the morphology of MIL-53(Fe) to be a unique prism-like structure and enhanced the degradation efficiency of IBP, which followed the pseudo-first-order rate kinetics. Among the prepared composites, BNFe-3 (3% BNNs) exhibited the highest IBP degradation activity and possessed strong stability after four cycles. Over 99% IBP removal was achieved at the irradiation time of 60 min. The promoted decomposition rate of IBP could be ascribed to be the activation of PS and the enhanced electrons transfer efficiency between BNNs and MIL-53(Fe). The scavenger studies and electron spin-resonance spectroscopy (ESR) demonstrated the generation of SO2-, OH and O2-, and all these radicals had the different contributions in IBP degradation. Based on the LC-MS-MS and TOC results, the possible decomposition pathways of IBP in BNFe-3/PS system were proposed. This work suggested that the BNNs/Fe-based MOFs composites and PS system had great potential in organic pollutants degradation in aqueous solution.

Liu N ，Wang J ，Tian M ，Lei J ，Wang J ，Shi W ，Zhang X ，Tang L ... -  《-》

Visible light enhanced persulfate activation for degradation of tetracycline via boosting adsorption of persulfate by ligand-deficient MIL-101(Fe) icosahedron.

In this work, Fe-based metal-organic frameworks (Fe-MOFs) are prepared by a simple solvothermal method, in which acetic acid/N, N-dimethylformamide (HAc/DMF) mixture solvents are employed to regulate the particle morphology, exposed facets and ligand defects. At HAc/DMF = 0/50, 5/45 and 8/42 (volume ratio), the irregular particles (MIL-53(Fe)), elongated icosahedrons (5H-MIL-101(Fe)) and icosahedrons (8H-MIL-101(Fe)) are obtained, respectively. Under visible light irradiation (λ > 420 nm) and the addition of sodium persulfate (PS), 5H-MIL-101(Fe) shows the highest degradation activity for tetracycline (TC). Specifically, 80% of TC has been removed by 5H-MIL-101(Fe) within 25 min, and the degradation kinetics rate is 3.03 times higher than that over MIL-53(Fe). The improvement of catalytic activity is mainly attributed to the active facets exposed and ligand defects of 5H-MIL-101(Fe). Density functional theory (DFT) calculation further confirms that the active facets exposed and ligand defects of 5H-MIL-101(Fe) favor the adsorption and activation of PS, benefiting the generation of •SO4-. Besides, a probable degradation pathway of TC is proposed based on trapping experiments and liquid chromatography-mass spectrometry (LC-MS) test. Furthermore, the toxicities of intermediates are predicted by the quantitative structure-activity relationship (QSAR) mathematical model. This work demonstrates that visible light enhanced PS activation (Vis-PSA) can more effectively degrade organic pollutants, and this work also provides a simple strategy to precisely regulate ligand defects and actively exposed facets of Fe-MOFs to enhance the adsorption and activation of PS.

Cheng G ，Yuan C ，Ruan W ，Ma B ，Zhang X ，Yuan X ，Li Z ，Wang D ，Teng F ... -  《-》

Highly efficient Fenton and enzyme-mimetic activities of NH(2)-MIL-88B(Fe) metal organic framework for methylene blue degradation.

He J ，Zhang Y ，Zhang X ，Huang Y ... -  《Scientific Reports》