Iron-based Metal-organic Frameworks Research Articles

Investigating the Catalytic Impact of Iron-Based Metal–Organic Framework Templates on the CO 2 -Derived Fischer–Tropsch Synthesis Process

Investigating the Catalytic Impact of Iron-Based Metal–Organic Framework Templates on the CO ₂ -Derived Fischer–Tropsch Synthesis Process

Biomimetic peroxidase MOF-Fe promotes bone defect repair by inhibiting TfR2 and activating the BMP2 pathway

BackgroundLarge bone defects pose a clinical treatment challenge; inhibiting transferrin receptor 2 (TfR2), which is involved in iron metabolism, can promote osteogenesis. Iron-based metal-organic frameworks (MOF-Fe) particles not only inhibit TfR2 but also serve as biomimetic catalysts to remove hydrogen peroxide in reactive oxygen species (ROS); excess ROS can disrupt the normal functions of osteoblasts, thereby hindering bone regeneration. This study explored the potential effects of MOF-Fe in increasing osteogenic activity and clearing ROS.MethodsIn vitro experiments were performed to investigate the osteogenic effects of MOF-Fe particles and assess their impact on cellular ROS levels. To further validate the role of MOF-Fe in promoting bone defect repair, we injected MOF-Fe suspensions into the femoral defects of SD rats and implanted MOF-Fe-containing hydrogel scaffolds in rabbit cranial defect models and observed their effects on bone healing.ResultsIn vitro, the presence of MOF-Fe significantly increased the expression levels of osteogenesis-related genes and proteins compared to those in the control group. Additionally, compared to those in the untreated control group, the cells treated with MOF-Fe exhibited a significantly increased ability to remove hydrogen peroxide from ROS and generate oxygen and water within the physiological pH range. In vivo experiments further confirmed the positive effect of MOF-Fe in promoting bone defect repair.ConclusionThis study supports the application of MOF-Fe as an agent for bone regeneration, particularly for mitigating ROS and activating the bone morphogenetic protein (BMP) pathway, demonstrating its potential value.

Magnetic iron-based metal organic framework as an adsorbent for magnetic dispersive solid-phase extraction of pyrene and phenanthrene in water samples

ABSTRACT A dispersive magnetic solid-phase extraction by means of core-shell iron-based metal-organic framework (Fe3O4- SiO2/EN@MIL-101(Fe)) nanospheres coupled with high-performance liquid chromatographic was developed for the determination of pyrene (Pyr) and phenanthrene (Phe) in water samples. Key parameters such as sorbent amount, sample volume, pH, extraction time, type and volume of elution, and desorption time were optimised by response surface methodology (RSM). Under the optimised conditions (sample volume: 5 mL, extraction time: 3 min, eluent: 3 mL acetonitrile: propanol, and desorption time: 3 min), the developed method showed a low detection and quantification limits (0.015 and 0.040 ng mL−1, respectively), good precision (< 9.8% RSD), wide linear range (0.06 - 10,000 ng mL−1, R2 > 0.99), high enrichment factors (49–57), good matrix effect (> 93.2%), high reusability (25 times), short extraction and desorption time (3 and 3 min, respectively), and high extraction recovery (96.5%). The established method was able to recover the Pyr and Phe from spiked real water samples with an extraction efficiency of 95.71% and 96.32%, respectively (RSD ≤ 9.52%).

Tailoring the structure of Fe-based NH2-MIL-88 via 2-hydroxyacetophenone for arsenic removal from aqueous solutions: Kinetics, adsorption isotherms studies, and optimization through Box-Behnken design

Over recent decades, industries have discharged significant volumes of arsenic-laden wastewater, resulting in severe contamination of groundwater and drinking water sources. Consequently, there has been a rise in the number of individuals afflicted with arsenic-related ailments. To tackle this issue, we explored the efficacy of a novel metal-organic framework (MOF) nanomaterial named 2HAP=N-MIL-88(Fe) for the removal of arsenic ions (As(III)) from water. This nanomaterial was synthesized through the reaction between 2-hydroxyacetophenone and an amino-functionalized iron-based MOF. We successfully produced and characterized the adsorbent using a range of techniques, including XRD, FT-IR, SEM, TGA, and BET. These methods affirmed the thermal resilience of the adsorbent and its substantial surface area of 180 m2/g. Batch trials were carried out to investigate various parameters, such as adsorbent dosage, concentration, duration, pH, and temperature. The optimum pH for effective adsorption was determined to be 4. Our findings revealed that the adsorption mechanism adhered to the Langmuir model concerning concentration and the pseudo-second-order model concerning duration. Moreover, the adsorption efficiency exhibited a rise with increasing temperature, suggesting an endothermic nature of the process. Additionally, we assessed the recyclability of the adsorbent and observed sustained high efficiency for up to 6 cycles. The sorption mechanism was identified as chemisorption, with an associated energy of 28.85 kJ·mol−1. In contrast to alternative adsorbents employed for As(III) elimination, the 2HAP=N-MIL-88(Fe) nanosorbent displayed remarkable efficacy, boasting a capacity of 265.5 mg/g. We delved into the mechanism of interaction between As(III) and the adsorbent, which could encompass ion exchange, electrostatic attraction, or hydrogen bonding. Notably, the adsorbent demonstrated chemical robustness, as evidenced by negligible deviations in the XRD patterns pre and post-regeneration. To enhance the adsorption outcomes, we employed the Box Behnken-design (BBD) method.

Graphdiyne chelated iron-based metal–organic frameworks for electrochemical sensing of antibiotic chloramphenicol with ultralow detection limit

Chloramphenicol (CAP), a broad-spectrum antibiotic agent that can inhibit protein synthesis, has caused environmental and human health problems upon excessive usage but to realize its ultrasensitive detection is still a great challenge. We report here the design and fabrication of a nanocomposite comprising graphdiyne (GDY) chelated iron-based metal–organic framework (Fe-MOF@GDY) with strong interfacial interaction to achieve high performance electrochemical sensing of CAP. Fe-MOF@GDY exhibits good selectivity, a linear range of 1 pM−24 mM and an ultralow detection limit down to 0.54 pM, among the best performance for CAP detection. It displays good reproducibility and storage stability with retained 98.4% of its initial response after 3 weeks. GDY with unique electronic structure enhances charge transfer of Fe-MOF for improved conductivity, and Fe-MOF nanoparticles are uniformly chelated on GDY for rich active sites towards CAP reduction. Fe-MOF also prevents GDY from being degraded, promoting long-term stability. A portable electrochemical chip is fabricated based on Fe-MOF@GDY, and is successfully used for accurate detection of CAP in lake water with recovery rates of 97.2–104.7%, demonstrating the practical on-site applications.

Combined application of surfactants and iron-based metal–organic framework nanoparticles for targeted delivery of insecticides

With the development of smart delivery systems for pesticides, many studies revealed that nanodelivery methods have great potential for use in efficient and sustainable agriculture; however, field application of the nanopesticides is still a challenge. In this study, the application of a chlorfenapyr (CF)-loaded iron-based metal–organic framework (CF@MIL-101-SL) to maize and its control efficacy for Spodoptera frugiperda were investigated in detail. The results showed that, compared with a suspension concentrate of CF (CF-SC), a solution of CF@MIL-101-SL with the surfactant aerosol OT exhibited excellent wetting, deposition and adhesion with maize leaves. The CF@MIL-101-SL NPs exhibited bidirectional translocation in maize, which significantly enhanced the transport of CF to the target tissues. Field trials revealed that CF@MIL-101-SL maintained > 75 % control efficiency after 21 d of spraying, indicating significantly greater insecticidal activity and persistence than CF-SC. Spray application of CF@MIL-101-SL gave high initial deposition rates, long half-lives on tender and old leaves and significantly reduced pesticide drift into the environment. Based on a biosafety assessment, spraying with CF@MIL-101-SL reduced the negative effects of CF on plants during the growth period. In addition, CF@MIL-101-SL increased the survival rate of Harmonia axyridis larvae and reduced the impacts of CF on the growth and intestinal damage of Harmonia axyridis. In summary, these results highlight the advantages of metal–organic framework delivery systems for multidimensional enhancement of pesticide efficacy, persistence, and safety and provide data on field application and the environmental risks of nanodelivery systems.

Controlled Synthesis of Preferential Facet-Exposed Fe-MOFs for Ultrasensitive Detection of Peroxides.

Exposing different facets on metal-organic frameworks (MOFs) is highly desirable to enhance the performance for various applications, however, exploiting a concise and effective approach to achieve facet-controlled synthesis of MOFs remains challenging. Here, by modulating the ratio of metal precursors to ligands, the facet-engineered iron-based MOFs (Fe-MOFs) exhibits enhanced catalytic activity for Fenton reaction are explored, and the mechanism of facet-dependent performance is revealed in detail. Fully exposed (101) and (100) facets on spindle-shaped Fe-MOFs enable rapid oxidation of colorless o-phenylenediamine (OPD) to colored products, thereby establishing a dual-mode platform for the detection of hydrogen peroxide (H2O2) and triacetone triperoxide (TATP). Thus, a detection limit as low as 2.06nm is achieved, and robust selectivity against a wide range of common substances (>16 types) is obtained, which is further improved by incorporating a deep learning architecture with an SE-VGG16 network model, enabling precise differentiation of oxidizing agents from captured images. The present strategy is expected will shine light on both the rational synthesis of nanomaterials with modulated morphologies and the exploitation of high-performance trace chemical sensors.

Design and Synthesis of an Integrated Nanozyme by Immobilizing Glucose Oxidase on an Iron-Based Metal-Organic Framework for the Development of a Glucose Assay

Design and Synthesis of an Integrated Nanozyme by Immobilizing Glucose Oxidase on an Iron-Based Metal-Organic Framework for the Development of a Glucose Assay

Synergistic degradation of oxytetracycline hydrochloride by persulfate activated by Ni-doped MIL-88A three-dimensional catalyst: Free radical and non-free radical pathways

The advanced oxidation technology of persulfate has great potential in removing pollutants. Appropriate bimetallic activation method has obvious synergistic effect on the formation of free radicals and non-free radicals, and can also promote the electron transfer process. Therefore, in this paper, Ni was doped on the iron-based metal organic framework (MIL-88A) to form bimetallic catalyst and used as persulfate activator for oxytetracycline (OTC) degradation. The introduction of Ni increased the specific surface area of the catalyst and significantly improved its catalytic performance. Within 30 min, the degradation efficiency of 5 mg/L OTC reached 81.30%. The used catalyst can be simply recovered by standing, and the catalytic stability is high. The composition of main reactive oxygen species (ROS) in pollutant decomposition was clarified through the analysis of degradation mechanism. In addition to typical •OH、SO4•− and O2•−, non-free radical 1O2 was also generated. Based on LC-MS detection and toxicological experiments, the possible degradation pathways were proposed and the toxicity was analyzed. This material provides a new insight for activating PS to remove refractory organic compounds, and promotes the application of Fe-MOF materials in environmental pollution remediation.

Low-crystallinity conductive multivalence iron sulfide-embedded S-doped anode and high-surface area O-doped cathode of 3D porous N-rich graphitic carbon frameworks for high-performance sodium-ion hybrid energy storages

Sodium-ion hybrid energy storages (SIHESs) are promising electrochemical energy storages for many applications, but their low energy and power densities are yet to be overcome. Herein, we report a strategy to realize ultrahigh-energy density and fast-rechargeable SIHESs. Ultrafine iron sulfide-embedded S-doped carbon/graphene (FS/C/G) anode materials are synthesized from iron-based metal-organic framework (MOF)/graphene oxide heterostructures via graphitic carbon formation and sulfidation. Operando and ex-situ analyses reveal that cycled iron sulfides are rescaled into low-crystallinity conductive fragments with Fe vacancies and multivalence Fe2+/Fe3+ states. Size reduction to fragments inside a 3D porous S-doped N-rich graphitic carbon framework induces high-capacity/high-rate FS/C/G performance. Moreover, 3D porous O-doped carbon cathode materials are synthesized from zeolitic imidazolate frameworks (ZIFs) via pyrolysis-assisted micropore and KOH-assisted mesopore formations. This ZIF-derived porous carbon (ZDPC) has a ∼20-fold higher surface area (3972 m2/g) than conventional ZDCs, O-induced micropores/N-rich sites for high capacity, heteroatom-induced ion-accessible defects/mesopores, and N-rich conductive graphitic carbon networks. Additionally, FS/C/G//ZDPC SHHES benefits from diffusion-controlled and capacitive reactions, as demonstrated by its hitherto highest energy density of 247 Wh kg-1 outperforming state-of-the-art SIHESs, fast-rechargeable power density (up to 34,748 W kg-1) exceeding battery-type reactions by more than 100 folds, and cycle stability with ∼100 % Coulombic efficiency over 5000 charge-discharge cycles.

Smart epoxy coating: g-C3N4 nanosheets loaded MOFs for enhanced anti-corrosion and UV resistance

Large lateral size g-C3N4 nanosheets (Graphite-like carbon nitride) were successfully prepared by surface polymerization. NH2-MIL-101 (Amino-functionalized iron-based metal–organic framework) was then modified on the surface of g-C3N4 nanosheets (NH2-MIL-101@g-C3N4) by an in-situ loading method to construct a long-term smart coating with high barrier, activity inhibition, and anti-UV aging. This novel approach marks a significant advancement in the development of smart coatings for long-term corrosion protection. Evaluation of the active corrosion inhibition of NH2-MIL-101@g-C3N4 (MCN) nanoparticles showed that the corrosion inhibition efficiency of MCN nanoparticles on carbon steel reached 79.3 % after 5 h. The addition of MCN nanoparticles to the epoxy coatings (MCN/EP) endowed the coatings with the ability to actively inhibit corrosion. The release of Fe3+ cations and NH2-BDC (2-aminoterephthalic acid) organic ligands from MCN at defects formed a protective film, effectively preventing further corrosion. The MCN/EP coating maintained a high Log|Z|0.01 Hz value (Impedance modulus at a frequency of 0.01 Hz) during the immersion period with excellent barrier properties. Notably, MCN significantly improved the water resistance, water contact angle, tensile properties, and thermomechanical properties of epoxy coatings after ultraviolet (UV) radiation, highlighting a remarkable enhancement in the coating's performance. The anti-corrosion of MCN/EP coating was unaffected by UV radiation, extending service life of the smart coating, with Log|Z|0.01 Hz values two orders of magnitude higher than pure EP after 300 h of UV radiation. This work presented innovative coating design and preparation methods to improve the performance and functionality of anti-corrosion coatings, making significant attempts in the field.

Cobalt-induced localized electronic reconstruction and global band structure adjustment enhance photo-Fenton-like activity in iron-based metal–organic frameworks

Modulations in interatomic localized electron density and occupation states are vital for facilitating efficient Photo-Fenton-like reactions in iron-based metal–organic frameworks (Fe-MOFs). Here, Co-doped Fe-MOFs (FeCox-MOFs) were synthesized through a one-step hydrothermal method, introducing Co(II) with a distinct Jahn-Teller effect and electronegativity. This led to local ligand deficiency, forming exposed Fe-O-Co clusters. This integration facilitated Co coordinatively unsaturated sites (CUSs) to partially acquire electrons from adjacent Fe CUSs, further optimizing the d-band center. As a result, the d-band centers of both Fe (-1.32 eV) and Co (-1.52 eV) CUSs in FeCo2/1-MOFs were higher than that of Fe sites (-1.87 eV) in Fe-MOFs, resulting in enhanced adsorption capability of persulfate (PMS). Notably, Co(II) underwent ligand-driven electron redistribution, populating antibonding orbitals (eg*) and increasing their energy, thereby elevating the conduction band. Concurrently, Co 3d orbitals served as donor energy levels, narrowing the band gap. With the tuned band structure, the eg* of Fe(III) sites experienced rapid electron population upon photoexcitation, expediting Co(III) reduction and enhancing PMS activation. This study provides a unique perspective on the catalytic application of FeCox-MOFs in photo-Fenton-like reactions.

Regulated Dual Defects of Bridging Organic and Terminal Inorganic Ligands in Iron-based Metal-Organic Framework Nodes for Efficient Photocatalytic Ammonia Synthesis.

Engineering advantageous defects to construct well-defined active sites in catalysts is promising but challenging to achieve efficient photocatalytic NH3 synthesis from N2 and H2O due to the chemical inertness of N2 molecule. Here, we report defective Fe-based metal-organic framework (MOF) photocatalysts via a non-thermal plasma-assisted synthesis strategy, where their NH3 production capability is synergistically regulated by two types of defects, namely, bridging organic ligands and terminal inorganic ligands (OH- and H2O). Specially, the optimized MIL-100(Fe) catalysts, where there are only terminal inorganic ligand defects and coexistence of dual defects, exhibit the respective 1.7- and 7.7-fold activity enhancement comparable to the pristine catalyst under visible light irradiation. As revealed by experimental and theoretical calculation results, the dual defects in the catalyst induce the formation of abundant and highly accessible coordinatively unsaturated Fe active sites and synergistically optimize their geometric and electronic structures, which favors the injection of more d-orbital electrons in Fe sites into the N2 π* antibonding orbital to achieve N2 activation and the formation of a key intermediate *NNH in the reaction. This work provides a guidance on the rational design and accurate construction of porous catalysts with precise defective structures for high-performance activation of catalytic molecules.

Facile synthesis of lignin-based Fe-MOF for fast adsorption of methyl orange

To rapidly remove dyes from wastewater, iron-based metal–organic frameworks modified with phenolated lignin (NH2-MIL@L) were prepared by a one-step hydrothermal method. Analyses of the chemical structure and adsorption mechanism of the NH2-MIL@L proved the successful introduction of lignin and the enhancement of its adsorption sites. Compared with NH2-MIL-101-Fe without phenolated lignin, the modification with lignin increased the methyl orange (MO) adsorption rate of NH2-MIL@L. For the best adsorbent, NH2-MIL@L4, the MO adsorption efficiency in MO solution reached 95.09% within 5 min. NH2-MIL@L4 reached adsorption equilibrium within 90 min, exhibiting an MO adsorption capacity of 195.31 mg/g. The process followed pseudo-second-order kinetics and the Dubinin-Radushkevich model. MO adsorption efficiency of NH2-MIL@L4 was maintained at 89.87% after six adsorption-desorption cycles. In mixed solutions of MO and methylene blue (MB), NH2-MIL@L4 achieved an MO adsorption of 94.02% at 5 min and reached MO adsorption equilibrium within 15 min with an MO adsorption capacity of 438.6 mg/g, while the MB adsorption equilibrium was established at 90 min with an MB adsorption rate and capacity of 95.60% and 481.34 mg/g, respectively. NH2-MIL@L4 sustained its excellent adsorption efficiency after six adsorption-desorption cycles (91.2% for MO and 93.4% for MB). The process of MO adsorption by NH2-MIL@L4 followed the Temkin model and pseudo-second-order kinetics, while MB adsorption followed the Dubinin-Radushkevich model and pseudo-second-order kinetics. Electrostatic interactions, π-π interactions, hydrogen bonding, and synergistic interactions affected the MO adsorption process of NH2-MIL@L4.

In-situ active sites analysis of bifunctional metal-organic frameworks for coupled adsorption and electrochemical oxidation of PPCPs

Pharmaceuticals and personal care products (PPCPs) pose a significant wastewater pollution concern. While electrochemical oxidation is promising, it struggles with slow mass transfer. To address this, we propose a novel strategy utilizing bifunctional metal–organic frameworks (MOFs) that couple an adsorbent with an electrocatalyst. The real active sites within iron-based MOFs responsible for the adsorption of PPCPs are MIL-101(Fe) molecules, while the in-situ formed active sites, α-FeOOH, accelerate the charge transfer under bias, contributing to the electrooxidation of PPCPs. The rapid destruction of adsorbed organics on the dual-functional electrode surface enables to release adsorption sites. This, in turn, paves the way for fast and efficient re-adsorption of PPCPs molecules, consequently promoting mass transfer. Iron-based MOFs exhibit excellent adsorption capacity (∼60 mg g−1 for sulfosalicylic acid, ∼15 mg g−1 for acetaminophen) and electrooxidation ability (94 % removal in 2 h, 31.2 kWh kg−1 COD) with good stability in realistic pharmaceutical wastewater treatment. This study offers a novel strategy for removing PPCPs using molecular electrocatalysts and provides new insights for designing and constructing MOFs for refractory wastewater treatment.

MXene-supported MIL-88A(Fe) as persulfate activator for removal of tetracycline.

The poor conductivity, poor stability, and agglomeration of iron-based metal organic framework MIL-88A(Fe) limit its application as persulfate (PS) activator in water purification. Herein, MXene-supported MIL-88A(Fe) composites (M88A/MX) were synthesized to enhance its adsorption and catalytic capability for tetracycline (TC) removal. Scanning electron microscope (SEM), X-ray diffractometer (XRD), Fourier transform infrared spectrometer (FT-IR), and X-ray photoelectron spectroscopy (XPS) were used to characterize prepared materials, confirming the successful attachment of MIL-88A(Fe) to the surface of MXene. M88A/MX-0.2 composites, prepared with 0.2g MXene addition, exhibit optimal degradation efficiency, reaching 98% under conditions of 0.2g/L M88A/MX-0.2, 1.0mM PS, 20ppm TC, and pH 5. The degradation rate constants of M88A/MX-0.2 were 0.03217min-1, which was much higher than that of MIL-88A(Fe) (0.00159min-1) and MXene (0.00626min-1). The removal effects of reaction parameters, such as dosage of M88A/MX-0.2 and PS; initial solution pH; and the presence of the common co-existing constituents (humic acid and the inorganic anions) were investigated in detail. Additionally, the reuse of M88A/MX-0.2 showed that the composites had good cycling stability by recurrent experiments. The results of electron paramagnetic resonance (EPR) and quenching experiments indicated that ·OH, ·SO4-, and ·O2- were involved in the M88A/MX-0.2/PS system where persulfate oxidation process was activated with prepared M88A/MX-0.2. In addition, the intermediates of photocatalytic degradation were determined by HPLC-MS, and the possible degradation pathways of the target molecules were inferred. This study offered a new avenue for sulfate-based degradation of Fe-based metal organic framework.

Fabrication of porous beta-cyclodextrin functionalized PVDF/Fe–MOF mixed matrix membrane for enhanced ciprofloxacin removal

Herein, we demonstrate the synthesis of beta-cyclodextrin (β–CD) functionalized polyvinylidene fluoride (PVDF) and iron-based metal-organic framework (Fe–MOF) mixed matrix membrane (MMM) for the enhanced removal of ciprofloxacin (CIP) from water. The membranes were prepared using the phase inversion technique with PVDF as the polymer matrix, Fe–MOF as the filler, and polyvinylpyrrolidone (PVP) as the porogen. The optimized MMM with 7% wt. Fe–MOF exhibited excellent performance with 87.6% removal efficiency. Moreover, the maximum adsorption capacity was 6.43 mg g–1. The β–CD functionalization improved the MMM hydrophilicity exhibited by the water contact angle (WCA) analysis (WCA = 55°). Furthermore, excellent adsorption performance can be attributed to the large Fe–MOF specific surface area (682.5 m2 g–1), the high porosity (77%), and the average pore diameter (395 nm) of the membrane. The inclusion of PVP (1% wt.) enhanced the porous nature of the MMM and, consequently, the adsorption performance for CIP. Notably, the hydrophilic and macroporous membrane showed good reusability with over 70% removal efficiency after five sequential adsorption–desorption cycles. The insights from this study suggest that the PMC–7 membrane can be an excellent candidate for the remediation of organic contaminants from aquatic environments.

Progress in the Elimination of Organic Contaminants in Wastewater by Activation Persulfate over Iron-Based Metal-Organic Frameworks.

The release of organic contaminants has grown to be a major environmental concern and a threat to the ecology of water bodies. Persulfate-based Advanced Oxidation Technology (PAOT) is effective at eliminating hazardous pollutants and has an extensive spectrum of applications. Iron-based metal-organic frameworks (Fe-MOFs) and their derivatives have exhibited great advantages in activating persulfate for wastewater treatment. In this article, we provide a comprehensive review of recent research progress on the significant potential of Fe-MOFs for removing antibiotics, organic dyes, phenols, and other contaminants from aqueous environments. Firstly, multiple approaches for preparing Fe-MOFs, including the MIL and ZIF series were introduced. Subsequently, removal performance of pollutants such as antibiotics of sulfonamides and tetracyclines (TC), organic dyes of rhodamine B (RhB) and acid orange 7 (AO7), phenols of phenol and bisphenol A (BPA) by various Fe-MOFs was compared. Finally, different degradation mechanisms, encompassing free radical degradation pathways and non-free radical degradation pathways were elucidated. This review explores the synthesis methods of Fe-MOFs and their application in removing organic pollutants from water bodies, providing insights for further refining the preparation of Fe-MOFs.

Ce/Fe bimetallic MOF derivatives in situ modified bulk carbon aerogel composite cathode for efficient heterogeneous electro-fenton degradation of chloramphenicol

In this study, we utilized a Ce-modified iron-based metal-organic framework derivative to in situ modify bulk CA (Ce/Fe@C-CA) as a bifunctional composite cathode to degrade chloramphenicol (CAP) in the heterogeneous electro-Fenton (EF) process. The composite cathode exhibited satisfactory CAP degradation efficiency, wide pH adaptability (2–9) and low metal leaching. Under the appropriate conditions (pH = 5, current density = 6 mA/cm2), 94.89% of CAP degradation efficiency was obtained within 60 min. The introduction of Ce increased the oxygen vacancy content, enhanced the cathodic electrochemical activity, promoted the production of a variety of reactive oxygen species and participates in the degradation of CAP, of which ·OH and 1O2 were dominant. Meanwhile, the electron transfer and synergistic catalysis between Ce and Fe promoted the regeneration of the metal active site, which was beneficial to improve the reuse stability of the Ce/Fe@C-CA cathode. The degradation pathway of CAP was obtained by DFT calculations and UPLC-MS/MS detection. This study not only proposed a novel bifunctional electro-Fenton cathode, but also provided a effective strategy for the treatment of actual pharmaceutical wastewater.

Enantiomeric analysis of chiral phenyl aromatic compounds by coated capillary electrochromatography based on aMOF-on-MOF stationary phase.

Chiral phenyl aromatic compounds (CPACs) are widely used in drug development, food/cosmetic production, and other organic synthesis processes, and their different enantiomers have distinct physiological activities and application differences. A double-layer metal-organic framework composite (MOF-on-MOF) was obtained by in situ synthesis of chiral metal-organic framework (CMOM-3S) on the surface of an iron-based metal-organic framework (NH2-MIL-101(Fe)). According to ourinvestigation, MOF-on-MOF composite was for the first time applied tothe stationary phase of capillary electrochromatography (CEC), and enantioseparations of eight CPACs were accomplished. Compared with single CMOM-3S, the enantioseparation performance of the coated capillary columns based on NH2-MIL-101(Fe)@CMOM-3S was improved by 34.07 ~ 720.0%. The R-/S-mandelic acid in actual sample (apricot leaves) was detected by the newly CEC system to be 0.0118mgmL-1 and 0.0523mgmL-1, respectively. The spike recoveries were 96.60 ~ 104.7%, indicating its good stability and accuracy. In addition, the selective adsorption capacity of MOF-on-MOF composites was verified by adsorption experiments.