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Graphical abstract Highlights • α-Fe 2 O 3 @g-C 3 N 4 catalyst was synthesized by a facile co-calcination. • It showed excellent photo-Fenton catalytic activity in a wide range of pH. • The high catalytic activity of the catalyst is due to its Z-scheme heterostructure. Abstract Fabricating heterojunction catalysts is a promising strategy for improving the performance in heterogeneous photo-Fenton reaction (PFR). Herein, a Z-scheme heterostructured α-Fe 2 O 3 @g-C 3 N 4 catalyst was successfully synthesized through the co-calcination of melamine and Fe-based MOF. The characterization results demonstrated that α-Fe 2 O 3 nanoparticles anchored on the surface of g-C 3 N 4 successfully. The degradation of tetracycline (TC) in visible-light/H 2 O 2 system was adopted to evaluate the photo-Fenton activity of the catalysts. About 92% of TC was degraded by the optimum composite FOCN-0.45 in 60 min; the degradation rate (0.042 min−1) of TC by the FOCN-0.45 is 6, 7 and 14 times higher than that by pristine MIL-53 (Fe) (0.007 min−1), α-Fe 2 O 3 (0.006 min−1) and g-C 3 N 4 (0.003 min−1), respectively. The prepared FOCN-0.45 composite exhibited excellent performance and high stability in a wide range of pH value. The promoted photo-Fenton catalytic efficiency benefited from the Z-scheme heterojunctions of α-Fe 2 O 3 @g-C 3 N 4 , which enhanced the separation ability of photo-generated charge carriers and increased the electrons that participated in Fe2+/Fe3+ cycle. The boosting OH radicals degraded organic pollutants as main reactive radicals. This work presents a feasible path to design and synthesize heterogeneous photo-Fenton catalysts for the removal of organic pollutants. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • TSMF heterojunction was implemented as a visible-light-driven photocatalyst. • The TSMF heterostructures enhanced the separation of photoexcited carriers. • The addition of 1T-MoS 2 changes the structure and morphology of MOFs. • The addition of 1T-MoS 2 significantly boosts the surface area of MOFs. Abstract High photocatalytic hole-electron pairs separation efficiency and the wide use of inexpensive and earth-abundant materials as cocatalysts in most semiconductor-based photocatalytic systems are desired for improving the photocatalytic activity and practical application. Herein, we report a facile one-pot solvothermal approach of integrating stable metallic nonmetal materials 1T-MoS 2 nanosheets with MIL-53(Fe) to form needle-shaped 1T-MoS 2 @MIL-53(Fe) (TSMF) composites. Interestingly, the introduction of 1T-MoS 2 turns nonspecial-structured MIL-53(Fe) into needle-like structure and the BET analysis reveals that the optimal TSMF composites possess abundant coexistence of micropores and mesopores with a large surface area of 337 m2 g−1, which is about 16 folds higher than that of the pure MOFs. Meanwhile, it is remarkable that the photocatalytic rate of ibuprofen (IBP) by optimal TSMF nanocomposites has improved 7.5 and 9.4 times compared to the pristine MIL-53(Fe) and 1T-MoS 2 , respectively. The photocatalytic efficiency of TSMF composites enhances due to the emerging micropores, which can provide more adsorption and reaction sites. In addition, the formed compact and uniform interface contact between 1T-MoS 2 sheets and MOF may dramatically accelerate the separation of the photo-induced charges, thus enhance the photocatalytic activity. We also study the photocatalytic mechanism combined the corresponding electrochemical testing and the photo-degradation intermediates identified by ion chromatography (IC) and LC–MS-MS, indicating that superoxide radicals (O 2 –), hydroxyl radical (OH) and electrons (e−) are the main active radicals in IBP photocatalysis and decarboxylation and hydroxylation are the main degradation pathways of IBP. [ABSTRACT FROM AUTHOR]

Great interest has been attracted to enhancing the photoelectrochemical performances of BiVO4. However, there have rarely been reported about addressing their PEC stability. Herein, it is proposed that Fe ions doping could enhance the stability and PEC performances of BiVO4, which may because it could improve the crystalline structure and eliminates the crystal defects of BiVO4. Moreover, it is found that metal-organic framework can play a co-catalyst role during the PEC experiments. We designed and fabricated nanoporous Fe-doped BiVO4 modified with MIL-53(Fe), which exhibits much higher PEC performance and stability than pristine BiVO4 and Fe-doped BiVO4. It is believed that MIL-53(Fe) can capture the photogenerated holes and thus facilitates the charge separation efficiency.Graphical Abstract: [ABSTRACT FROM AUTHOR]

Highlights • MIL-53(Fe) nanocomposites were successfully formed by an in situ synthesis. • The ratio of FeCl 3 ·6H 2 O and H 2 BDC effect the structure and photocatalytic activity of MIL-53(Fe). • The synthesis temperature effect the structure and photocatalytic activity of MIL-53(Fe). Abstract In this study, Fe-based metal-organic frameworks (MOFs) nanocomposite MIL-53(Fe) was developed by a facile solvothermal method, and the effect of synthesis conditions on MIL-53(Fe) was investigated. The as-prepared materials were characterized by X-ray diffraction, Fourier transform infrared, scanning electron microscope (SEM), and UV–vis diffuse reflectance spectra. Rhodamine B used as a model pollutant to detect the photocatalytic activity of these materials. The best synthesis temperature of MIL-53(Fe) was 150 °C and the optimum ratio of FeCl 3 ·6H 2 O and C 8 H 6 O 4 was 1:2. SEM results showed that the relatively uniform morphology might be beneficial to the photocatalytic reaction. The results could further support exploitation of experimental conditions for the synthesis of MOFs materials with high catalytic performance. [ABSTRACT FROM AUTHOR]

Photocatalytic activity of titanium(IV) oxide (TiO2) can be enhanced through modification of its surface‐active sites. Here, iron(III) carboxylate [MIL‐53[Fe]]‐incorporated TiO2 (as MIL‐53(Fe)/TiO2) was prepared using a hydrothermal method. This material was then calcined at 500°C to obtain a MIL‐53(Fe)‐derived γ‐Fe2O3/TiO2 photocatalyst. A photocatalytic study of MIL‐53(Fe)/TiO2 and MIL‐53(Fe)‐derived γ‐Fe2O3/TiO2 toward cationic methylene blue (MB) and anionic methyl orange (MO) showed that MIL‐53(Fe)/TiO2 (0.25 wt%) and MIL‐53(Fe)‐derived γ‐Fe2O3/TiO2 (0.75 wt%) resulted the best degree of dye degradation. The MIL‐53(Fe)‐derived γ‐Fe2O3/TiO2 (0.75 wt%) composite for instance is capable of degrading almost 100% of 20‐ppm MB and MO, respectively, within 6 hr. Photocatalytic degradation of MB and MO was well fitted to the Langmuir‐Hinshelwood pseudo‐first order kinetics model, which indicates physisorption as the key partway that facilitates dye decomposition on the surface of a photocatalyst under UV‐A irradiation. This study provides new insights into the exploration of MILs/TiO2 materials for the environmental remediation and pollution control. MIL‐53(Fe) incorporated with TiO2 was prepared using hydrothermal and calcined methods for studying its photocatalytic activity toward methylene blue (MB) and methyl orange (MO). MIL‐53(Fe)/TiO2 (0.25 wt%) and MIL‐53(Fe)‐derived γ‐Fe2O3/TiO2 (0.75 wt%) can remove 70 and 96% of 20‐ppm MB and 89 and 96% of 20‐ppm MO under UV‐A irradiation, respectively. The photocatalysis of both composites was well fitted to the Langmuir‐Hinshelwood pseudo‐first order reaction kinetics model. MIL‐53(Fe)‐derived γ‐Fe2O3/TiO2 is more superior than the uncalcined composite. This study opens up a new way for the exploration of MOFs and TiO2 materials for the environmental remediation and pollution control. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hydrothermal synthesis method is used to prepared the double cone hexagonal prism shape MIL-53(Fe) NPs. • Choline chloride–ethylene glycol DES is encapsulated on hydrophilic MIL-53(Fe) nanoparticles. • The DES-coated MIL-53(Fe) is incorporated in PVDF pervaporative MMMs for phenol removal study. • The hydrophilicity of DES@MIL-53(Fe) nanoparticles can be attributed to significant boost in water flux. • The observed water flux and phenol removal of A4 membrane is 126 L m−2h−1 and 93.85%, respectively. Novel hydrophilic pervaporative mixed matrix membranes (MMMs), comprising deep eutectic solvent-coated MIL-53(Fe) embedded polyvinylidenefluoride (PVDF) matrix, are prepared to remove phenol from the water. Double cone hexagonal prism type MIL-53(Fe) nanofillers are first synthesized by hydrothermal method and then encapsulated with deep eutectic solvent (DES) solution by a deep coating process. The DES-coated MIL-53(Fe) nanofillers are added to the PVDF matrix to prepare the MMMs using the non-solvent-induced phase-separation (NIPS) process. The prepared DES@MIL-53(Fe) and MMMs are characterized by various analytic techniques to verify the successful addition of the nanofillers into the PVDF matrix. The highest pure water flux (PWF) values of nearly 126 L m−2h−1 are observed with a DES@MIL-53(Fe) loading of 7.5 wt% in the polymer dope solution for MMMs, which is three times higher than pure PVDF membrane values (41.5 L m−2h−1). The DES@MIL-53(Fe)/PVDF MMMs showed nearly 215% enhancement in pure water flux (131.66 L m−2h−1) and ∼ 107% enhancement in the phenol removal efficiency (93.22%) for the 50-ppm phenol solution as compared to pure PVDF membranes. Further, the experiments are carried out within a wide range of feed concentrations (feed concentration: 15–90 ppm) and feed pH (pH: 1–13) to study the separation performance of the MMMs. [ABSTRACT FROM AUTHOR]

The complicated oily wastewater containing hazardous organics post a great challenge to the membrane separation technology. Herein, a multilayer porous multifunctional MXene/MOF composite membrane with high permeability and photocatalytic degradation performance was prepared by embedding rod-shaped MIL-53(Fe) into layered MXene nanosheets and self-assembling them onto porous polyacrylonitrile fibrous mat. It was found that the embedment of rod-like MIL-53(Fe) with rough nanostructures could effectively avoid the dense physical stacking of MXene nanosheets and regulate the layer spacing, which was conducive to the enhancement of water channel and permeability of membrane. Moreover, the hydrophilic modification of TA could render the super-wetting feature (WCA=0°, UOCA>150°) and enhance the oil resistance of the membrane. Thence, the composite membrane exhibited favorable separation flux (904.3 ∼ 1226.5 L·m−2·h−1) and retention rate (99.06 ∼ 99.62%) for different O/W emulsions. In addition, the coupling of rod-like MIL-53(Fe) and MXene nanosheets endowed the composite membrane with efficient photocatalytic performance, which could degrade various dyes contained in oily wastewater (CV: 62.4%, MeB: 99.0%, CR: 79.5%, MO: 84.1%). Overall, this study opens up a new way for the preparation of super-wetting and multi-functional fibrous composite membrane, showing the broad application prospects in the purification of multi-component oily wastewater. [Display omitted] • Novel rod-like MIL-53(Fe) intercalated MXene lamellar membrane was fabricated. • The interlayer spacing and wettability (WCA=0°, UOCA>150°) can be well regulated. • The high permeability (up 1226.5 L·m−2·h−1) for O/W emulsions was achieved. • The membrane offered efficient photocatalytic degradation for MeB (99.0%). [ABSTRACT FROM AUTHOR]

Metal-organic frameworks (MOFs), as a new type of crystal materials, are considered a kind of promising photocatalysts. In this work, a novel Bi 2 S 3 /MIL-53(Fe) heterojunction photocatalyst was successfully prepared via a facile two-step method (hydrothermal and water bath). The characterization means, including XRD, SEM-EDS, FT-IR, XPS, PL, and UV–Vis, were employed to analyze the structural and morphological properties of Bi 2 S 3 /MIL-53(Fe). The photocatalytic performance of Bi 2 S 3 , MIL-53(Fe), and Bi 2 S 3 /MIL-53(Fe) was evaluated by the removal efficiency of the photocatalytic degradation of tetracycline (TC, 10 mg/L) under visible light irradiation (λ > 420 nm). The results show that the photocatalyst BSM-10 (the mass ratio of Bi 2 S 3 to MIL-53(Fe) is 10:90) exhibits improved photocatalytic performance compared to Bi 2 S 3 and MIL-53(Fe), showing the optimum photocatalytic activity (the degradation efficiency of TC is 90.9% within 120 min), and the corresponding first-order reaction rate constant is about 3 and 2 times higher than that of MIL-53(Fe) and Bi 2 S 3 , respectively. The improvement in photocatalytic activity is attributable to the efficacious separation of photogenerated electron-hole pairs and significant acceleration of charge transfer rate. Based on the free radical trapping experiment and ESR test results, combined with the band structure of MIL-53 (Fe) and Bi 2 S 3 , we speculate that a heterojunction is formed between MIL-53 (Fe) and Bi 2 S 3 , and the proposed Z scheme mechanism can well explain the enhanced catalytic activity of BSM-10. The Bi 2 S 3 /MIL-53 (Fe) heterojunction photocatalyst synthesized in this work has potential application value for removing the typical pollutant tetracycline from water. [Display omitted] • A novel Bi 2 S 3 /MIL-53(Fe) heterojunction photocatalyst was prepared by a facile method. • BSM-10 shows efficient photocatalytic performance for tetracycline degradation. • The Z scheme mechanism can well explain the enhanced catalytic activity of BSM-10. [ABSTRACT FROM AUTHOR]

Abstract The development of composite photocatalyst is a promising direction for improving photocatalytic performance of decomposition of organic dyes. This study aimed to fabricate two composite photocatalysts using either Fe 3 O 4 or NiFe 2 O 4 with MIL-53(Fe) as heterogeneous catalysts for the degradation of rhodamine B (RhB) under visible light irradiation by a 40 W compact fluorescent lamp. The physicochemical, the surface, the magnetic and the energy band gap of the photocatalyst were characterized by XRD, FT-IR, Raman, FE-SEM, UV–vis DRS, Brunauer–Emmett–Teller (BET), and VSM. From the photocatalytic activities test results, the NiFe 2 O 4 -doped MIL-53(Fe) sample expressed a higher photocatalytic degradation capacity of RhB than that of Fe 3 O 4 /MIL-53(Fe) sample, significantly better than that of the bare of Fe 3 O 4 , NiFe 2 O 4 , and MIL-53(Fe). [ABSTRACT FROM AUTHOR]

Novel metal-organic framework/stannous sulfide (MIL-53(Fe)/SnS) nanocomposite photocatalysts were successfully synthesized by a one-step deposition process. The structure, composition and optical properties of the MIL-53(Fe)/SnS composite were systematically characterized by the X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, Fourier transform-infrared spectroscopy, UV–vis diffuse reflection spectroscopy and photoluminescence analysis. The photocatalytic performance of MIL-53(Fe)/SnS composite has been evaluated in the reduction of chromium (VI) under visible-light irradiation. Compared with pure MIL-53(Fe) and SnS, the MIL-53(Fe)/SnS composite exhibited enhanced photoreduction capability of chromium (VI) due to the strengthened absorption in the visible region, higher electron-hole separation rate and larger specific area. The MIL-53(Fe)/SnS composite with MIL-53(Fe) adding of 15 mg displayed optimal chromium (VI) reduction rate of 0.01878 min −1 , which was about 7.5 and 5.2 times than pure MIL-53(Fe) and SnS, respectively. The active species superoxide radical ( O 2 – ), electron(e − ) and hole(h + ) are essential toward chromium (VI) reduction. Lastly, a possible photocatalytic mechanism is proposed. [ABSTRACT FROM AUTHOR]

Metal-organic frameworks (MOFs) have attracted tremendous interest as photocatalysis for the destruction of organic contaminants. Herein, we synthesize a Fe-based MOF namely MIL-53(Fe), combined with Fe(III) and percarbonate, exhibits photocatalytic activity for the destruction of Sulfamethazine (SMT) under visible LED light irradiation. The morphology and physicochemical properties of the MIL-53(Fe) were determined using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectra (EDS), Fourier transform infrared spectroscopy (FTIR) and photoluminescence spectroscopy (PL). The results indicated that the photocatalytic performance of MIL-53(Fe) with unsatisfactory efficiency resulted from the rapid recombination of photogenerated electrons and holes. This may be suppressed through the introduction of an external electron acceptor (e.g., Fe(III) and percarbonate) to the catalytic process. It could be seen that the SMT degradation efficiency in the system of Vis/MIL-53(Fe)/Fe(III)/SPC attained nearly 90% within 60 min, while only 12% achieved in the system of Vis/MIL-53(Fe). The quenching experiments and EPR analysis were employed to illuminate the predominant reactive species in the system of Vis/MIL-53(Fe)/Fe(III)/SPC. It must be mentioned that the higher separation efficiency of photoinduced electron- hole pairs was achieved via the addition of Fe(III). The accelerated photocatalytic degradation of SMT could be attributed to the subsequent formation of reactive species, which were generated from the activation of SPS by Fe(II) reduced from Fe(III) in the Vis/MIL-53(Fe)/Fe(III)/SPC system. Furthermore, the mineralization of SMT was systematically investigated, as well as the effects of operating parameters (e.g., the dose of catalyst, the concentration of Fe(III), and pH). The work has expanded the possibility of MOFs as visible light responsive photocatalysts together with percarbonate for the remediation of contaminated water. [ABSTRACT FROM AUTHOR]

In this study, metal-organic framework (MOF) MIL-53(Fe) was synthesized. MIL-53(Fe) is capable of activating peroxymonosulfate to achieve highly efficient rhodamine B (RhB) degradation under visible light, and MIL-53(Fe) shows good photocatalytic activity in a wide pH range. The results of the recycling experiments, X-ray diffraction patterns, and Fourier transform infrared spectra of MIL-53(Fe) before and after the catalytic reaction revealed that MIL-53(Fe) is stable. Electron paramagnetic resonance tests indicated that sulfate radicals are the dominant reactive species in RhB degradation. This study provides some guidance in the exploration and utilization of MOFs for environmental remediation. [ABSTRACT FROM AUTHOR]

A novel system combining photocatalysis and capacitive deionization (CDI) was proposed and used to efficiently remove the total Cr from the aqueous solution for the first time. MIL-53(Fe) with wide visible-light absorption was successfully prepared by a simple solvothermal method, and applied as positive photoelectrode material of the photocatalysis-CDI system (PCS) to convert Cr(VI) to Cr(III). Active carbon was used as negative electrode material to absorb Cr(III). An enhanced removal of Cr(VI) can be obtained by applying visible light irradiation and 1.3 V direct current (DC) voltage simultaneously and the Cr(VI) removal can reach a maximum value of 81.6%, much higher than those under individual 1.3 V DC voltage (39.4%) or visible light irradiation (54.2%), demonstrating the synergistic effect from CDI and photocatalysis. More importantly, effective removal of the total Cr with high removal ratio (72.2%) can be achieved, which is difficult to be realized using current other technologies. The strategy in this work provides a promising method for the complete removal of high-valence heavy metal ions. [ABSTRACT FROM AUTHOR]

A series of MIL-53(Fe) materials was synthesized using a solvothermal method under different temperature and time conditions and were used as catalysts to activate persulfate and degrade Orange G (OG). Influences of the above conditions on the crystal structure and catalytic behavior were investigated. Degradation of OG under different conditions was evaluated, and the possible activation mechanism was speculated. The results indicate that high synthesis temperature (larger than 170 °C) leads to poor crystallinity and low catalytic activity, while MIL-53(Fe) cannot fully develop at low temperature (100 or 120 °C). The extension of synthesis time from 5 h to 3 d can increase the crystallinity of the samples, but weakened the catalytic activity, which was caused by the reduction of BET surface area and the amount of Fe (II)-coordinative unsaturated sites. Among all the samples, MIL-53(Fe)-A possesses the best crystal structure and catalytic activity. In optimal conditions, OG solution can be totally decolorized after degradation for 90 min, and a removal rate of 74% for COD was attained after 120 min. The initial solution pH had great influence on OG degradation, with the greatest removal in acidic pH environment. ESR spectra showed that sulfate radical (SO 4 − ), hydroxyl radical (OH ), persulfate radical (S 2 O 8 − ), and superoxide radical (O 2 ) exist in this system under acidic conditions. Furthermore, with the increase of pH, the relative amount of O 2 increases while that of OH and SO 4 − decreases, resulting in a reduced oxidizing capacity of the system. [ABSTRACT FROM AUTHOR]

The construction of heterojunction and surface defect engineering are attractive methods for the improvement of the photocatalytic performance of the semiconductors. Herein, a novel Z-scheme heterojunction DyVO 4 /MIL-53(Fe) composed of DyVO 4 with oxygen vacancies (OVs) and MIL-53(Fe) was for the first time fabricated by a facile solvothermal method. The prepared photocatalyst were characterized by a variety of techniques. The photocatalytic activity was assessed by the photodegradation of tetracycline (TC) under visible light irradiation. The characterization results shows that DyVO 4 /MIL-53(Fe) exhibits excellent visible light response. The introduction of OVs on the surface of DyVO 4 accelerated the separation of photogenerated carriers. Furthermore, OVs and Z-scheme hetero constructure showed synergism in promoting the transfer and separation of the photoinduced charge carriers. The prepared DyVO 4 /MIL-53(Fe) has excellent photocatalytic performance for TC degradation. At pH of 5, the degradation efficiency of TC over the optimum composite DM30 (30 wt% DyVO 4 /MIL-53(Fe)) is up to 98.2%, and TOC removal rate is 46.2%. The hydroxyl radical (•OH), superoxide radicals (•O 2 −), and holes (h+) were all found to act as main active species in TC photodegradation. The enhanced photocatalytic activity is attributed to the excellent visible light response and the obviously promoted transfer and separation of the photogenerated electrons and holes. • A novel DyVO 4 /MIL-53(Fe) heterojunction with surface oxygen vacancies was first reported. • Z-scheme charge transfer mechanism was confirmed on the interface between DyVO 4 and MIL-53(Fe). • Z-scheme hetero-structure and oxygen vacancy cooperatively promote the charge transfer. • DyVO 4 /MIL-53(Fe) exhibits excellent photocatalytic activity for degradation of tetracycline. • The rationally matched band position makes.•O 2 −, •OH and h+ act as active species in TC degradation. [ABSTRACT FROM AUTHOR]

Iron based MIL-53 (Fe) was synthesized using solvothermal and ionothermal methods. Afterwards, the synthesized materials were sulfated to increase the acidic property. Characterization of the synthesized and sulfated materials were performed using FT-IR, BET, XRD and TGA methods. The sulfated materials were used in the esterification reaction of acetic acid to test the catalytic activity. The effect of synthesis method on the structure of MIL-53 (Fe) and effects of temperature, time and sulfation of samples on the conversion of acetic acid were also studied. Also, reusability of sulfated samples was achieved by washing with pure water. In ionothermal synthesis of iron based metal organic framework, deep eutectic solvent formed when choline chloride and dimethyl urea was used as solvent. [ABSTRACT FROM AUTHOR]

In this study, hybrid nanocomposites based on Fe-based MOF and graphitic carbon nitride (g-C 3 N 4 ) were developed by a facile solvothermal method. The as-prepared materials were characterized by XRD, FESEM, TEM, XPS and PL analysis. It was showed that the introduction of a certain amount of g-C 3 N 4 on the surface of MIL-53(Fe) would improve the separation and migration rate of photo-induced charges, consequently resulting in the boost of photocatalytic efficiency. Compared with g-C 3 N 4 and MIL-53(Fe), the CMFe composites displayed more excellent visible light-resposive photocatalytic activity for the reduction of Cr(VI). The optimal doping content of g-C 3 N 4 in g-C 3 N 4 /MIL-53(Fe) composite was determined to be 3.0 wt%, and it showed about 2.1 and 2.0 times as high photocatalytic efficiency for the reduction of Cr(VI) as that of pure g-C 3 N 4 and MIL-53(Fe), respectively. Meanwhile, the composite exhibited good reusability and stability in the process of cyclic experiments. A possible photocatalytic reaction mechanism was also investigated in detail by the related electrochemical analysis. [ABSTRACT FROM AUTHOR]

The development of efficient materials for removing pharmaceuticals from water has been a matter of great concern. As a new class of porous materials, metal-organic frameworks (MOFs) have attracted considerable attention in the field of environmental remediation. In this article, a photocatalytic adsorbent MIL-53(Fe) was successfully prepared by solvothermal method and used for the removal of two typical pharmaceuticals clofibric acid (CA) and carbamazepine (CBZ) from water. MIL-53(Fe) exhibited good adsorption performance and the maximum adsorption capacities of CA and CBZ are about 0.80 mmol/g and 0.57 mmol/g, respectively. The adsorption mechanisms of CA and CBZ are mainly due to electrostatic interaction and π-π interaction, respectively. Further, MIL-53(Fe) exhibited high photocatalytic activity and stability under visible light. The photocatalytic efficiency could be improved significantly with the addition of a small amount of H 2 O 2 , and the corresponding photodegradation efficiencies for CA and CBZ both reached up to 90%, which are higher than those of Fe(II)/H 2 O 2 and TiO 2 under visible light. The photocatalytic performance was strongly dependent on the solution pH. The Fenton-like reaction, charge carriers directly generated in the photo-excited MIL-53(Fe) and the synergistic effect of H 2 O 2 were the main mechanisms. The formation of humic acids-like and fulvic acids-like organic matter in the degradation process was detected by 3D EMMs. MIL-53(Fe) also revealed excellent performance for the removal of CA and CBZ from real municipal wastewater and river water. Therefore, MIL-53(Fe) may be used as a promising photocatalytic adsorbent for wastewater purification. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs) may be promising multifunctional materials attributing to their large internal surface areas and high porosities that can favor charge transport. In this article, MIL-53(Fe) has been investigated as an anode material for Li-ion batteries. It showed decent performance on account of the redox reaction (Fe 3+ ↔ Fe 0 ). However, the carboxylate groups of terephthalate acid ligands did not show electrochemical activity due to the poor electrical conductivity of MIL-53(Fe) and the formation of thick solid electrolyte interphase layer. In this case, reduced graphene oxide (RGO) was then composited to resolve the problem, which named as MIL-53(Fe)@RGO. The composite exhibited better electrochemical performance than the sole MIL-53(Fe). Specifically, a reversible discharge specific capacity of 550 mA h g −1 could be still achieved at 100 mA g −1 after 100 cycles within the voltage range of 0.01–3.0 V, an reversible discharge capacity of about 300 mA h g −1 was obtained even at 2 A g −1 . These values are much higher than those of currently used graphitic materials. RGO makes it even more possibility for MOFs to be adopted as electrode materials for Li-ion batteries. [ABSTRACT FROM AUTHOR]

As a pharmaceutical pollutant, doxycycline causes contamination when enters into the environment. In this research MIL-53(Fe), and its magnetic hybrid MIL-53(Fe)/Fe 3 O 4 were synthesized and employed for removal of doxycycline from aqueous solutions. The adsorbents were characterized by XRD, SEM, BET, FTIR, EDAX, VSM and TG-DTG technique. The effect of different variables such as DOC concentration, pH, contacting time, and adsorbent dose on the removal efficiency was studied and under optimized conditions the adsorption capacity of 322 mgg −1 was obtained. The adsorption process was kinetically fast and the equilibration was attained within 30 min. The used adsorbent was easily separated from the solution by applying external magnetic field. The regenerated adsorbent retained most of its initial capacity after six regeneration steps. The effect of ionic strength was studied and it was indicated that removal of doxycycline from salt-containing water with moderate ionic strengths was quite feasible. Langmuir, Freundlich, Tempkin and Dubinin–Redushkevich isotherms were employed to describe the nature of adsorption process. The sorption data was well interpreted by the Longmuir model. [ABSTRACT FROM AUTHOR]

Metal organic frameworks (MOFs) are fascinating materials for diverse applications due to their adjustability of aperture and structure. Herein, a three-dimensional iron-based MOF with BDC linker (BDC = 1,4-benzenedicarboxylate), commonly known as MIL-53(Fe), has been synthesized and successfully composited with anionic resin (Amberlite IRA 200) and cationic resin (Amberlite IRA 900) resulting solid composite photocatalysts, AMIL-53 (Fe) and DMIL-53(Fe), respectively. In the novel composite photocatalysts, bulky MIL-53(Fe) MOF solids are used as both a support to anchor the finely ground Amberlite IRA resin powders and as a visible light active component for the degradation of organic pollutants in water. In addition to being a traditional support, the resins here were used as a co-catalyst (with loading ration of the resin to MIL-53(Fe) is controlled around 20 wt%) to capture and transfer pollutant molecule from bulk solution into the active centers of the composited catalysts. Such an immobilization of the resins significantly alters MIL-53 (Fe) activity and degradation selectivity of dye pollutants; after 120 min of visible light illumination (λ ≥ 420 nm) removal yield of SRB (24%) by the bare MIL-53 (Fe) was apparently improved to 96% after MIL-53 (Fe) was modified by Amberlite IRA 900, DMIL-53(Fe). The tunable degradation order was demonstrated by employing AMIL-53 (Fe) for the selective degradation of cationic dyes while DMIL-53 (Fe) for the degradation of anionic dyes. Furthermore, the composites activity was optimized by controlling resin to MOF ratio during immobilization. Immobilization also improves ease of separation and recyclability of the original MOF. Especially, AMIL-53 significantly reduces iron ion leaching resulting in an enhanced stability. The photocatalytic mechanism under visible-light irradiation is also discussed. [ABSTRACT FROM AUTHOR]

[Display omitted] • A spindle-shaped Ag/AgCl modified MIL-53(Fe) (AM) heterojunction was synthesized. • Highly sunlight-driven photocatalytic performance for Cu-EDTA was gotten by AM. • The special Z-scheme configuration might contribute to the greatly improvement. • Metal Ag acted as charge transmission bridge to promote the charges separation. • Surface plasmon resonance effect widened its spectral response to visible-light. Heavy metal complexes exhibit strong toxicities to aquatic ecosystems, and quite resistant to traditional treatments. Bare MIL-53(Fe) could effectively decomplex Cu-EDTA under UV-light irradiation but not visible-light. How to realize its highly sunlight-driven decomplexation has attracted great attention. In this study, Ag-based modification strategy was selected, and Ag/AgCl nanoparticles were prepared synchronously to improve the sunlight-driven photocatalytic activity of MIL-53(Fe) for Cu-EDTA decomplexation. The Ag/AgCl modified MIL-53(Fe) (AM) heterojunction composites displayed greater photocatalytic decomplexation for Cu-EDTA than bare MIL-53(Fe). 93 % of Cu-EDTA elimination and nearly 60 % mineralization were achieved within 120 min simulated sunlight irradiation by the AM with Ag/Fe molar ratio of 1:2. The special Z-scheme configuration contributed to the significant improvement, in which metal Ag nanoparticles played the role of charge transmission in favor of promoting the generated electron-hole pair separation under UV-light irradiation, and surface plasmon resonance (SPR) effect was conducive to broadening its spectral response to visible-light region. Meanwhile, strong oxidizing species, including h+, ·O 2 –, ·OH, and 1O 2 , especially for h+, dominated the Cu-EDTA decomplexation, and some small organic acids and alcohols were the main products after 120 min irradiation. [ABSTRACT FROM AUTHOR]

[Display omitted] • A MWCNTs/MIL-53(Fe) nanocomposite is fabricated by one-pot hydrothermal process. • MWCNTs/MIL-53(Fe) delivers a superior high removal efficiency of As(V) at 95.1%. • MWCNTs/MIL-53(Fe) exhibits better water stability than the pure MIL-53(Fe). • The As(V) adsorption conforms to PSO kinetic and Redlich-Peterson isotherm models. • The adsorption mechanism is caused by interactions of hydrogen bond and complexation. Arsenic is a toxic carcinogen, and arsenic pollution in groundwater is one of the most serious environmental problems in the world. Thus, it is an urgent problem to efficient removal of arsenic from groundwater. In this work, a novel MWCNTs/MIL-53(Fe) nanocomposite was successfully synthesized to improve the water stability of MIL-53(Fe) by incorporation of carboxylated multi-walled carbon nanotubes (MWCNTs) using a one-pot hydrothermal method, and was then used to efficiently adsorb As(V) ions from groundwater. Adsorption experimental results demonstrated an ultrafast adsorption rate of As(V) on the MWCNTs/MIL-53(Fe) nanocomposites in solution pH values of 3 to 10, and the adsorption equilibrium could be reached in circa 20 min with an adsorption capacity of 27.24 mg·g−1 in a low As(V) concentration of 10 mg·L−1. The adsorption kinetics of As(V) on the MWCNTs/MIL-53(Fe) was found in line with the pseudo-second-order (PSO) kinetic model, and was simultaneously controlled by both internal diffusion and liquid film diffusion. The adsorption isotherm data conformed to the Redlich-Peterson isotherm model, indicating both physical and chemical adsorption occurred at heterogeneous interfaces. Moreover, the postulated adsorption mechanism of As(V) on MWCNTs/MIL-53(Fe) nanocomposites was ascribed to hydrogen-bond interaction, electrostatic attraction and chemical complexation. Therefore, the as-prepared MWCNTs/MIL-53(Fe) nanocomposites not only exhibit superior water stability and outstanding adsorption performance in removing arsenic-contaminated groundwater, but also offer a novel insight for rational preparation of water-stable MOF-based composites. [ABSTRACT FROM AUTHOR]

[Display omitted] • MIL-53(Fe) was immobilized into the PVDF to obtain mixed-matrix membranes. • MIL-53(Fe)/PVDF was integrated into the photocatalytic membrane reactor to remove tetracycline. • Removal of tetracycline was enhanced by the combination of separation and catalysis mechanisms. • Over 99.0 % of tetracycline was removed by the photocatalytic membrane reactor. • Tetracycline was degraded by h+ and •OH radicals. This work demonstrates the synergistic effect of two-unit operations: filtration and photocatalysis to remove tetracycline (TC) from wastewater by immobilizing MIL-53(Fe) photocatalyst into the poly (vinylidene fluoride) (PVDF) matrix to create a mixed-matrix membrane (MMM) in a photocatalytic membrane reactor (PMR). Herein, 1.0–5.0 wt% of MIL-53(Fe) was blended into a PVDF-based casting solution to obtain MMMs after phase-inversion. The addition of MIL-53(Fe) resulted in an increased viscosity of the casting solution which caused the macrovoids decorating the cross-section of the polymer matrix to be suppressed, consequently decreasing the bulk pore size from 0.06 to 0.014 µm. Moreover, it also increased the bulk tortuosity by suppressing the macrovoid formation which enhanced the depth-filtration mechanism of the modified membranes, particularly P10M5 which delivered the highest rejection of 87 % against TC. Meanwhile, LC/MS technique confirmed the degradation of TC under UV illumination and revealed that P10M5 provided optimal condition for degrading TC with 93 % degradation efficiency. The trapping experiments revealed that the dominating reactive oxidation species responsible during the degradation process were h+ and •OH species. Our results indicate that TC was photocatalytically degraded through a series of de-amidation, de-hydroxymethylation, and ring opening reactions. Through the integration of size-exclusion/depth-filtration mechanisms offered by the membrane, and degradation process provided by MIL-53(Fe), the PMR system using P10M5 successfully removed tetracycline in the permeate and < 1 % undegraded TC remained. The findings of this study offer a viable approach to solve the crises of pharmaceutical products in wastewater by simultaneously rejecting and degrading these compounds. [ABSTRACT FROM AUTHOR]

MIL-53(Fe)/chitosan composite hydrogel spheres were formed by chitosan (CS) coating MIL-53(Fe). The structural and physicochemical properties of the material were characterized by SEM, FTIR, XRD, TGA, BET, and Zeta potential. The adsorption properties of the adsorbents were systematically analyzed for different conditions, such as pH, contact time, adsorbent dosage, initial concentration, and temperature. The experimental data were fitted using adsorption isotherms, adsorption kinetics, and adsorption thermodynamics models. The results show that the pseudo-first-order model and Liu model are fitted to the adsorption kinetics and adsorption isotherm respectively. The adsorption capacity of CR reached the maximum value of 590.8 mg g−1 at 298 K. The adsorption efficiency of the composite material for CR was high, and when 100 mg L−1 CR solution was used, 99.97% of CR could be removed by reaching adsorption equilibrium. After three times of adsorption, the recovery was still close to 85%. The adsorption mechanism is mainly the synergistic effect of pore filling, ionic interactions, and hydrogen bonding. • MIL-53(Fe)/chitosan hydrogel spheres have a high adsorption capacity for CR. • The adsorption mechanism of MIL-53(Fe)/chitosan hydrogel spheres on CR was analyzed. • The complicated separation steps of mother MIL-53(Fe) and water can be avoided. • It can remove trace amounts of CR that cannot be solved by physicochemical methods. • After repeated adsorption three times, the recovery was still close to 85%. [ABSTRACT FROM AUTHOR]

[Display omitted] • MIL-53(Fe)/TCPP was fabricated by a convenient one-pot hydrothermal method. • A ligand-regulated strategy to enhance the photocatalytic activity of MIL-53(Fe). • The incorporation of TCPP promotes photogenerated carrier transport. • MIL-53(Fe)/TCPP showed superior catalytic activity for CO 2 cycloaddition reaction. The porphyrin-doped MIL-53(Fe) (MIL-53(Fe)/TCPP) nanomaterials were constructed by a simple one-pot hydrothermal method. The properties of materials were characterized by analytical methods including XRD, SEM, FTIR, XPS, UV–vis, PL, etc. The results displayed that the MIL-53(Fe)/TCPP not only maintains the similar structural characteristics of MIL-53(Fe) but also significantly strengthens the optical performance. The optimal MIL-53(Fe)/TCPP displayed superior photocatalytic activity for the cycloaddition reaction of CO 2 with propylene oxide under visible light (λ = 460 nm) irradiation at ambient conditions, and its yield was increased by about 10 times higher than that of the original MIL-53(Fe). [ABSTRACT FROM AUTHOR]

Various analytical applications of metal-organic frameworks (MOFs) have been rapidly developed in the past few years. However, the employment of MOFs as catalysts in chemiluminescence (CL) analysis is rare. Here, for the first time, we found that MIL-53(Fe) MOFs could significantly enhance the CL of luminol in the presence of HO in an alkaline medium. The CL intensity in the luminol-HO-MIL-53(Fe) system was about 20 times higher than that in the luminol-HO system. Moreover, the XRD pattern of MIL-53(Fe) after CL reaction was almost the same as that of the original MIL-53(Fe), confirming the catalytic role of MIL-53(Fe) in the luminol-HO-MIL-53(Fe) system. The possible mechanism behind the enhancing phenomenon was discussed based on the results from the CL spectra, FL probe experiments, and active oxygen species measurements. By coupling with the glucose oxidase-based catalytic oxidation reaction, a sensitive and selective CL method was developed for the detection of glucose. There is a linear relationship between the logarithm of CL intensity and the logarithm of glucose concentration in the range from 0.1 to 10 μM, and a detection limit of 0.05 μM (S/N = 3) is obtained. The proposed method has been applied to the determination of glucose in human serum samples with satisfactory results. [ABSTRACT FROM AUTHOR]

A series of MIL-53(Fe)-graphene nanocomposite photocatalysts were synthesized by a facile one-pot solvothermal reaction. All materials have been thoroughly characterized by FT-IR, SEM, TEM, PXRD, UV–vis DRS and PL analysis. It was demonstrated that the introducing of graphene on the MIL-53(Fe) would minimize the recombination of photogenerated electron-hole pairs, thus, leading to the enhancement of photocatalytic activity. MIL-53(Fe)-graphene nanocomposite was an efficient catalyst towards the photocatalytic selectively oxidation of alcohols to the corresponding aldehydes or ketones under visible light and ambient conditions. High selectivity of the aldehydes or ketones (99%) were obtained. Meanwhile, the catalyst can be recycled at least four times without loss of catalytic efficiency. A possible photocatalytic reaction mechanism involving a direct photogenerated hole-oxidation process was also investigated in detail by the active species trapping experiments and the related electrochemical analysis. [ABSTRACT FROM AUTHOR]

The degradation in liquid water of two iron-containing MOFs MIL-100(Fe) and MIL-53(Fe) synthesized in fluoride-free conditions was studied. It was found that dispersing the MOFs in deionized water (1 mg/mL) results in the decrease of pH to 2.9 for MIL-100(Fe) and to 4.5 for MIL-53(Fe). Given this finding the stability of the MOFs in liquid water was characterized under two different sets of conditions: 1) reflux in water at 100 °C under obtained pH and 2) at ambient temperature under adjusted pH 7. After reflux of MIL-100(Fe) at 100 °C its XRD pattern remains unchanged, however a strong decrease of its BET surface area and appearance of α-Fe 2 O 3 nanoparticles point out to a partial degradation of the MOF. Reflux of MIL-53(Fe) in water at 100 °C results in its partial degradation yielding H 2 BDC molecules intercalated in the pores of the remaining MOF particles. To study the degradation of MIL-100(Fe) and MIL-53(Fe) under adjusted pH 7 at room temperature the solids were dispersed in water and then NaOH solution was added in order to maintain a constant pH value. It was found that under such conditions the frameworks of both materials collapse yielding poorly crystallized 6-line ferrihydrite. This finding suggests that the notion of “stability in deionized water” frequently used for MOFs needs to be completed by specifying the exact pH value at which the tests are realized. [ABSTRACT FROM AUTHOR]

Conventional drug administration suffers from several drawbacks, including a lack of specificity for diseased tissue, the necessity of large and frequent doses, and adverse side effects. Great effort is currently being devoted to developing nanoparticle-based therapeutics capable of prolonging drug administration and providing better control. Here we demonstrate the use of flexible microporous MIL-53(Fe) and mesoporous MIL-101 and SBA-15 as matrices for the adsorption and in vitro drug delivery of acetaminophen, progesterone, and stavudine. A drug loading of 20 wt.% was achieved for each of the nanomaterials using an incipient wetness impregnation procedure. BET, DSC, and XRPD analyses indicated that the entire loaded amount of each of the model drugs had successfully been incorporated within the mesoporous channels of both MIL-101 and SBA-15. DSC analysis evidenced that a portion of each of the model drugs had deposited onto the outer surface of MIL-53(Fe) particles; however, the portion of each drug that had incorporated within the microporous channels was slowly delivered in a diffusion-controlled process, which occurred over a period of up to six days for acetaminophen. These results demonstrate the unique ability of MIL-53(Fe) to adapt its porosity and optimize drug–matrix interactions. Owing to its larger pore diameters and weaker host–guest interactions, MIL-101 release times were shorter, yet still prolonged, as evidenced by the complete release of stavudine after five days. Complete release of each of the drugs from SBA-15 occurred very quickly as a result of rapid drug dissolution and diffusion out of the mesopores. [ABSTRACT FROM AUTHOR]

• Millimeter-size polymer anchored MIL-53(Fe)@polyethersulfone balls were validated for elimination of carbamazepine. • Improved photocatalytic performance of MIL-53(Fe) by 4 times through the chelation of Polyethersulfone. • the composite balls can be recovered by simple precipitation and filtration method. Fe-MOFs are expected to be the candidates for heterogeneous Fenton catalysts due to their porous channel and high specific surface area feature. However because of their small size they are difficult to recycle, and the low Fe(II) concentration make them low efficiency for H 2 O 2 activation. Herein, we report millimeter-scale polymer anchored porous MIL-53(Fe) composite balls with highly improved Fenton-like performance and easy recycling for the elimination of carbamazepine. It is prepared via MIL-polyethersulfone dope and solvent/water exchange method with organic ligand substitution strategy that affording S O and C O mixed-coordination. The degradation rate constant for MIL-53(Fe)@PES is 4 times that of pure MIL-53(Fe), while the degradation rate constant of photo Fenton is 79 times of dark one. The composite balls can be recovered by simple precipitation process and the removal efficiency of carbamazepine still reach 80% after 5 cycles of regeneration. The mechanism of photo-Fenton degradation of carbamazepine were proposed. [ABSTRACT FROM AUTHOR]

[Display omitted] • A series of BC@FexC were synthesized via solvothermal reaction and high-temperature calcination. • 1.0-BC@FexC exhibited excellent performance to activate PDS for NOR degradation. • The catalytic mechanism of NOR degradation by the 1.0-BC@FexC/PDS system was investigated. • The 1.0-BC@FexC/PDS system showed potential in simulated wastewater treatment. The magnetic Fe-MOFs derivatives obtained by high-temperature calcination under inert atmosphere have been studied and acted as high-efficiency catalysts in wastewater remediation. However, due to the shortcoming that the unstable structure of Fe-MOFs derivatives tends to collapse and agglomerate easily, it is necessary to find a support to improve its dispersibility and stability. In this work, an effective method was provided to fabricate biochar-loaded MIL-53(Fe) derivatives (BC@FexC) to activate peroxydisulfate (PDS) for norfloxacin (NOR) degradation. The efficiency of the BC@FexC/PDS system for NOR removal can reach to 91.2% within 15 min, and the reaction constant (k) was 52.15 times of BC/PDS and 22.19 times of FexC/PDS. Characterization results illustrated that the superior spatial pore structure and exposed active sites of BC@FexC allowed NOR to diffuse and interact with the catalyst efficiently. OH, SO 4 − and 1O 2 were the main reactive oxygen species involved in NOR degradation. Moreover, the BC@FexC/PDS system exhibited excellent stability that almost unaffected by various environmental conditions (such as tap water, river water, and medical wastewater), which would provide a reference path for application in actual water treatment. [ABSTRACT FROM AUTHOR]

MIL-53(Fe) catalyst has been widely used to treat the pollutants in water. However, the limited number of electrons in MIL-53(Fe) catalyst has always affected the rate at which Fe3+ can be reduced to Fe2+. We modulated iron-based metal–organic frameworks (MOFs) using organic ligands modified with chlorine functional groups. The characterization results indicate that the 2Cl-MIL-53(Fe) catalyst exhibited the optimal photoelectric properties while maintaining the original structural characteristics. The experimental analyses and the first-principles study suggest that the introduction of a chlorine functional group not only reduced the band gap width and enhanced the visible-light absorption capacity, but also significantly enhanced the electron cloud density of Fe–O clusters. This could further accelerate the redox cycle of Fe(III)/Fe(II), beneficial for H 2 O 2 activation. The constructed Cl-MIL-53(Fe) catalyst exhibited a 3.8 times higher reaction rate constant than pure MIL-53(Fe) catalyst. The specific TCH degradation pathway and mechanism of 2Cl-MIL-53(Fe) treatment are proposed. This study provides a new strategy for iron-based MOFs as a heterogeneous photo-Fenton catalyst to degrade pollutants in water. [Display omitted] • Cl-MIL-53(Fe) was prepared via chlorine functional group modification in MIL-53(Fe). • Cl-MIL-53(Fe) catalyst exhibited remarkable TCH degradation efficiency. • Cl functional group induced light absorption increase & band gap reduce of MIL-53(Fe). • Cl functional group increased electron cloud density and Fe2+/Fe3+ redox. [ABSTRACT FROM AUTHOR]

In the last decade, Metal-organic frameworks (MOFs) were utilized to uptake pollutants from water due to their distinctive features such as tunability, high surface area, and ease of functionalization. In the present research, a novel amine-functionalized MIL-DETA-n (n ​= ​DETA molar ratio) was prepared through the impregnation method using diethylenetriamine (DETA) and MIL-53 (Fe) and characterized using SEM, EDX, XRD, FT-IR, and BET analyses. The MIL-DETA-n was used to adsorb As(V) from aqueous media, and adsorption capacity was reached 137.5 ​mg/g. DETA functionalization of MIL-53(Fe) decreased Fe leaching and kept Fe concentration below 0.3 ​mg/L as the maximum contaminant level. The effect of different parameters such as temperature, pH, trace arsenate concentrations, co-existing ions, and reusability was studied. The kinetic and thermodynamic studies demonstrated that adsorption follows the pseudo-second-order model, and the equilibrium data fits with the Langmuir isotherm. For the first time, the MIL-DETA-n was successfully employed to remove arsenic from surfaces and groundwater. [Display omitted] • Successfully amine-functionalization of MIL-53(Fe) using diethylenetriamine to prepare MIL-DETA. • High performance of MIL-DETA adsorbent to uptake As(V). • Reaching arsenate removal capacity to 137.5 ​mg/g. • Decrease in Fe leaching after amine-functionalization. • The superior efficiency of MIL-DETA in polluted surfaces and groundwater. [ABSTRACT FROM AUTHOR]

The oil vine-like structural of MIL-53(Fe) decorated by N-CQDs exhibits brilliant abilities of As(III) removal efficiency which is achieved through photocatalytic oxidating the As(III) and simultaneous adsorbing the generated arsenate [As(V)]. In situ embed N-CQDs into MIL-53(Fe) was proved to lead an increased charge transportation and improved utilization of the electrons and holes and the edge structure of N-CQDs3/MIL-53(Fe) manifested the significantly As(III) removal ability. [Display omitted] • A promising bifunctional photocatalyst/adsorbent with oil vine like structural of MIL-53(Fe) decorated by N-CQDs was prepared for the first time. • The composite material of MIL-53(Fe) with in situ embedded N-CQDs exhibited brilliant abilities of As(III) oxidation and removal efficiency. • In situ embedding N-CQDs into MIL-53(Fe) was proved to lead an increased charge transportation and improved utilization of the electrons and holes. • The edge structure of N-CQDs3/MIL-53(Fe) manifested the significantly As(III) removal ability. It has been ever attracting increasingly growing demand to develop highly efficient method of aqueous arsenites [As(III)] removal due to the high toxicity of arsenic in drinking water. This work presents an oil vine-like structural MIL-53(Fe) modified by nitrogen doped carbon quantum dots (N-CQDs) with excellent As(III) removal property, which is achieved through the photocatalytic oxidation of the As(III) and simultaneous adsorbed the generated arsenate [As(V)]. The abilities of As(III) oxidation and removal efficiency for N-CQDs3/MIL-53(Fe) are over 6 times higher than that of pure MIL-53(Fe). The impressively capability of N-CQDs3/MIL-53(Fe) in photocatalytic oxidation and adsorption is attributed to the accelerated separation of photogenerated electron-hole by the in situ embedded N-CQDs. Moreover, the results of the experimental analysis and density functional theory (DFT) DFT calculations confirm that the edge structure of C/O site significantly improves the removal ability of As(III) by forming bidentate C-O-As bonds and occupying coordinatively unsaturated atoms. Therefore, based on the excellent performance and reusability of N-CQDs3/MIL-53(Fe) in As(III) removal, it offers a new potential strategy to develop high efficient MOF based materials for As(III) removal. [ABSTRACT FROM AUTHOR]

In recent years, Metal-organic frameworks (MOFs) have received significant attention to adsorb arsenic from aqueous media. In this study, magnetic Fe 3 O 4 @SiO 2 -MIL-53(Fe) was prepared and characterized by XRD, SEM, EDX, FTIR, VSM, and BET techniques. The synthesized Fe 3 O 4 @SiO 2 -MIL-53(Fe) was successfully applied to remove arsenate with a maximum adsorption capacity of 70.1 mg/g. The adsorbent capability was tested in different pH, co-existing ions, and trace arsenate concentrations, and their particles were easily separated from the solution by an external magnetic field. Adsorption and VSM tests showed that the adsorbent capacity and magnetic properties were preserved after four cycles. The adsorption process obeyed the pseudo-second-order model and the experimental data well fitted with Langmuir monolayer isotherm. Immobilization of Fe 3 O 4 @SiO 2 nanoparticles into the MIL-53(Fe) structure was reduced iron ions leaching to the solution. For the first time, the Fe 3 O 4 @SiO 2 -MIL-53(Fe) composite was successfully used to remove arsenic from contaminated surfaces and groundwater. [Display omitted] • Successfully synthesis of Fe 3 O 4 @SiO 2 -Mil-53(Fe) composite. • High performance of composite in As(V) removal. • Application of composite in arsenic removal from contaminated surfaces and groundwater for the first time. • Reduction in iron leaching to the solution. • The efficiency of composite to uptake trace As(V) contamination. [ABSTRACT FROM AUTHOR]

In this work, novel heterostructure photocatalyst contains MIL-53(Fe) and sliver chromate (Ag 2 CrO 4) were successfully prepared through a precipitation method. The prepared composites included various weight percentages (25, 50, and 75%) of MIL-53(Fe). PXRD, FESEM, EDX, BET-BJH, UV–Vis, DRS, and FTIR techniques were used to study the structural, chemical, and optical properties of the prepared nanocomposites. Introducing Ag 2 CrO 4 particles on the surface of MIL-53(Fe) with a high surface area led to the increase in the photocatalytic activity of Ag 2 CrO 4 to remove AO7 dye under visible light irradiation. DRS analysis indicated that Ag 2 CrO 4 /MIL-53(Fe) has a narrower band-gap compared to MIL-53(Fe), and it can absorb light in the visible light region. The effect of photocatalyst dosage, initial solution pH, and initial dye concentration were investigated to evaluate the photocatalytic activity of prepared samples. The photo-degradation activity of AO7 dye was tremendously enhanced over Ag 2 CrO 4 /50%MIL-53(Fe) sample under the simulated solar light, and •OH and h+ were the main photodegradation mechanism. So, prepared Ag 2 CrO 4 /MIL-53(Fe) nanocomposites can be suggested as a potential and appropriate option to solve water pollution. In this study, Ag 2 CrO 4 /MIL-53(Fe) was successfully synthesized with different percentages of MIL-53(Fe) Metal-organic Framework (MOF) via ultrasound assisted precipitation method. The properties of the as-prepared samples were studied by XRD, FESEM, EDX, BET-BJH, FTIR, DRS, and pH pzc techniques. The results revealed that the Ag 2 CrO 4 /MIL-53(Fe) sample possesses superior photocatalytic performance with 91.5% degradation of 30 ppm AO7 in 140 min. It could be attributed to the increases the surface area, the pore volume, and pore diameter, as well as efficient homogenous distribution of active sites due to the use of ultrasound irradiation. Furthermore, the presence of MIL-53(Fe) increases light absorption and reduces the recombination rate of electron-hole pairs. [Display omitted] • Successfully synthesis of Ag 2 CrO 4 /MIL-53(Fe) by ultrasonic assisted precipitation method. • Promising physicochemical and optical properties of the synthesized nanocomposites. • Superior photocatalytic activity of Ag 2 CrO 4 /MIL-53(Fe) (91.5% removal of AO7). • Investigation of the effective operating parameters on AO7 photodegradation. [ABSTRACT FROM AUTHOR]

Metal–organic framework Mil-53(Fe) was successfully synthesized through hydrothermal reaction and added to a precursor solution containing polyacrylonitrile powder for electrospinning. This product membrane exhibits excellent performance in emulsion separation and dye degradation. [Display omitted] • High porosity and specific surface area with Mil-53(Fe) reference in PAN spun film. • MOF combined with electron acceptors enables dye degradation in the absence of light. • High throughput and retention rate of emulsion can be achieved by gravity filtration. Environmental pollution caused by oily wastewater, which frequently contains large amounts of organic dyes, has become increasingly serious. Super-wetting materials possessing special wettability have been widely used in membrane separation technology, with the excellent emulsion separation performance shown to be related to the specific surface morphology. In this study, metal–organic framework Mil-53(Fe) was successfully synthesized through solvothermal reaction and added to a precursor solution containing polyacrylonitrile powder for electrospinning. The resulting fibrous matrix membrane exhibites superamphilicity in air, superoleophobicity in water, and superhydrophobicity in oil, with separation efficiency for various oil-in-water emulsions reaching over 95%. Furthermore, this membrane exhibites self-cleaning and corrosion-resistant properties, and could be recycled after ten consecutive cycles. The degradation efficiency toward several organic dyes was simulated in visible light, combined with persulfate, achieving 100% degradation. Therefore, this membrane has potential applications in emulsion separation and dye degradation. [ABSTRACT FROM AUTHOR]

The biocompatible MIL-53(Fe) was synthesized and utilized to load Ag ions via a simple impregnation resulting in an antibacterial system Ag@MIL-53(Fe). The materials were characterized by PXRD and SEM. The loading capacity and antibacterial performance of powders at different mass ratio were further investigated. The Ag ions content of Ag@MIL-53(Fe) reached to maximum (about 40.62 ​wt%) at the mass ratio of 1:1 which was measured by ICP. The inhibition zone radius of material (Ag 40.62 ​wt%) showed the optimal efficiency against both Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) while MIL-53(Fe) demonstrated negligible antimicrobial performance. The excellent antibacterial activity and desirable biocompatibility of Ag@MIL-53(Fe) implied its promising prospect in antibacterial. Ag ions as a typical antibacterial agent was loaded into MIL-53(Fe) via a simple impregnation method resulting in an antibacterial system Ag@MIL-53(Fe). MIL-53(Fe) exhibited the poor inhibition of S. aureus and E. coli while the obvious inhibition zone of Ag@MIL-53(Fe) was observed, the phenomena implied the excellent antibacterial behaviors of Ag@MIL-53(Fe) against both S. aureus and E. coli. [Display omitted] • A biocompatible MOF MIL-53(Fe) was synthesized. • Ag ions was loaded into MIL-53(Fe) to construct an antibacterial system Ag@MIL-53(Fe). • Ag@MIL-53(Fe) (Ag 40.62 wt%) showed optimal efficiency against both S. aureus and E. coli. [ABSTRACT FROM AUTHOR]

• The photo-Fenton catalyst MIL-53(Fe)/BiOI were prepared by co-precipitation method. • MIL-53(Fe)/BiOI can effectively degrade tetracycline in mild pH. • The enhanced degradation ability depends on the synergy of photocatalysis and Fenton. • Singlet oxygen and hole were demonstrated to be the main active species. • The possible reaction pathway and mechanism diagram were proposed. [Display omitted] In this work, a series of MIL-53(Fe)/BiOI composites were synthesized by a combined hydrothermal and facile co-precipitation method. The heterojunctions were further used as photocatalysts for tetracycline (TC) degradation in photo-Fenton system. The TC degradation rate constant for MIL-53(Fe)/BiOI (0.0906 min−1) was 2.1 and 2.3 times higher than that for MIL-53(Fe) (0.0432 min−1) and BiOI (0.0389 min−1), respectively. The photoelectrical characterization results suggested that the enhanced photocatalytic activity of the MIL-53(Fe)/BiOI composite was attributed to the high electron and holes separation efficiency. The scavenging experiment results and electron spin resonance analysis demonstrated that h+ and singlet oxygen were the main reactive species in the degradation process. The possible photo-Fenton degradation mechanism was further elucidated based on the band structures of MIL-53(Fe) and BiOI with the generation process of reactive species. This work provided a new idea to construct metal-organic-framework-based composite photocatalysts for photo-Fenton system, and it is also promising for the applications in environmental restoration and protection field. [ABSTRACT FROM AUTHOR]

• Successful development of novel low-crystalline bimetallic MOFs as excellent photo-Fenton catalysts. • Achievement of intensified synergism between hetero-metal nodes in the low-crystalline bimetallic MOFs. • Low-crystalline state, further strengthened the role of doped metal. • The electron-rich Fe sites were formed in the low-crystalline MOFs. • Low-crystalline MOFs enable exposure of more metal CUSs, beneficial for H 2 O 2 coordination. In this study, the low-crystalline bimetallic metal-organic frameworks (MOFs) of L-MIL-53(Fe, Mn) and L-MIL-53(Fe, Cu) (MIL: Material of Institute Lavoisier) were successfully developed as photo-Fenton catalysts, exhibiting significantly enhanced degradation performance (15.2 and 2.49 times increase in reaction rate constant, respectively) for ciprofloxacin (CIP) in contrast to their crystalline counterparts. That were mainly attributed to the intensified synergism between hetero-metal nodes. Specifically, taking L-MIL-53(Fe, Mn) as an example, the formed electron-rich Fe sites along with the strengthened roles of Mn for enlarged specific surface area, enhanced visible-light absorption and separation and transportation of photo-induced carriers in the low-crystalline state, are responsible for acceleration of Fe(II)/Fe(III) and Mn(II)/Mn(III) cycles, beneficial for H 2 O 2 activation. Moreover, increased metal coordinately unsaturated sites (CUSs) are favorable for more H 2 O 2 coordination. This work gives a deep insight into the heterogeneous photo-Fenton mechanism of the bimetallic MOFs in their low-crystalline state. [ABSTRACT FROM AUTHOR]

MIL-53(Fe) is a metal organic framework that has been recently considered a heterogeneous photocatalyst candidate for the degradation of water pollutants under visible or solar radiation, though stability studies are rather scarce in the literature. In this work, MIL-53(Fe) was successfully synthesized by a solvothermal method and fully characterized by X-ray diffraction (XRD), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), N2 adsorption–desorption isotherm, Thermogravimetric analysis coupled with mass spectrometry (TGA-MS), UV-visible diffuse reflectance spectroscopy (DRS), elemental analysis and wavelength dispersive X-ray fluorescence (WDXRF). The effects of pH, temperature, solar radiation and the presence of oxidants (i.e., electron acceptors) such as ozone, persulfate and hydrogen peroxide on the stability of MIL-53(Fe) in water were investigated. The as-synthetized MIL-53(Fe) exhibited relatively good stability in water at pH 4 but suffered fast hydrolysis at alkaline conditions. At pH 4–5, temperature, radiation (solar and visible radiation) and oxidants exerted negative effect on the stability of the metal–organic framework (MOF) in water, resulting in non-negligible amounts of metal (iron) and linker (terephthalic acid, H2BDC) leached out from MIL-53(Fe). The photocatalytic activity of MIL-53(Fe) under simulated solar radiation was studied using phenol and metoprolol as target pollutants. MIL-53(Fe) on its own removed less than 10% of the pollutants after 3 h of irradiation, while in the presence of ozone, persulfate or hydrogen peroxide, complete elimination of pollutants was achieved within 2 h of exposure to radiation. However, the presence of oxidants and the formation of some reaction intermediates (e.g., short-chain carboxylic acids) accelerated MIL-53(Fe) decarboxylation. The findings of this work suggest that MIL-53(Fe) should not be recommended as a heterogeneous photocatalyst for water treatment before carrying out a careful evaluation of its stability under actual reaction conditions. [ABSTRACT FROM AUTHOR]

As a green and eco-friendly power generation technology, microbial fuel cell (MFC) still faces challenge for application due to the low power density. To achieve the purpose, a novel bio-functional metal organic framework (MOF) is fabricated through a facile hydrothermal method and applied as anodic material in the MFC. The results indicate that the NH 2 -MIL-53(Fe) anode decreases the electron transfer resistance, enhances the bio-electrocatalystic properties and facilitates bacterial conglutination on the anodic surface. A great energy output of 2.55 W m−3 is achieved by the MFC with NH 2 -MIL-53(Fe) anode, which is 53% larger than that of MFC with acetylene black anode (1.66 W m−3), while the dominant genus on the NH 2 -MIL-53(Fe) anode are exoelectrogens Geobacter (abundance of 20.95%). The excellent results mainly ascribed to the synergy of unique structure of MOF and each component of NH 2 -MIL-53(Fe), including enlarged electrochemical active area, improved the bio-affinity and extracellular electron transfer rate by iron oxide and amino groups. This work provides valuable information for applying more bio-functional MOFs to construct high-performance MFCs. [ABSTRACT FROM AUTHOR]

• MIL-53(Fe)/CQDs/MNPs composites were successfully prepared by a facile two-pot route. • MIL-53(Fe)/CQDs/2%Au showed superior Cr(VI) photoreduction performance. • This sample showed excellent photoactivity for simultaneous removal Cr(VI) and dyes. • CQDs and MNPs were decorated on MOFs photocatalysts for the first time. Industrial sewage often contain metal ions and dyes, and it is difficult to efficiently remove them simultaneously. In this work, novel ternary MIL-53(Fe)/carbon quantum dots/noble metal (MIL-53(Fe)/CQDs/MNPs, MNPs = Ag, Pd, Au) nanocomposites have been rationally constructed and successfully fabricated by a facile two-step strategy with self-assembling and in-situ photoreduction. The resulting MIL-53(Fe)/CQDs/2%Au composite exhibits excellent photoactivity for the Cr(VI) reduction, the reduction ratio is nearly 100% after 20 min of visible light illumination. The rate constant of MIL-53(Fe)/CQDs/2%Au is calculated to be 0.1820 min−1, which is around 7.4, 2.76, 1.77 and 1.47 times higher than that of as-prepared MIL-53(Fe), MIL-53(Fe)/CQDs, MIL-53(Fe)/CQDs/2%Ag and MIL-53(Fe)/CQDs/2%Pd, respectively. More significantly, MIL-53(Fe)/CQDs/2%Au nanocomposite has been proven to serve as bifunctional photocatalyst for simultaneously removing Cr(VI)/dye mixed system pollutants. The superior photoactivity may be due to the enhanced light absorption intensity, the superior electrical conductivity of Au and CQDs, as well as surface plasmon resonance (SPR) effect of Au. In particular, the possible photocatalytic reaction mechanism has been carefully investigated and proposed. [ABSTRACT FROM AUTHOR]