Metal Organic Framework MIL-101 Research Articles

Rapid and selective removal of bisphenol S from environmental samples by surface-imprinted polymer synthesized based on metal-organic framework MIL-101(Cr)

In this study, a novel, surface-imprinted polymer (MIL-101@MIP) was successfully synthesized using the metal-organic framework MIL-101(Cr) with a large specific surface area as a carrier, which achieved rapid and selective removal of bisphenol S (BPS) from environmental samples. The structure and morphology of MIL-101@MIP were characterized using SEM, XPS, FTIR, TGA, BET, and XRD techniques. The results show that MIL-101@MIP has rough surface morphology and good thermal stability. The large specific surface area (1251.6 m2 g-1) of MIL-101@MIP provides more imprinting sites in MIL-101@MIP; thus, the maximum adsorption capacity of BPS reached 87.76mgg-1 with good imprinting factor 2.08, and equilibrium was achieved in only 10min. Moreover, the process of BPS adsorption onto MIL-101@MIP followed the pseudo-second-order kinetics and Langmuir isothermal adsorption models. In addition, the MIL-101@MIP was utilized as an adsorbent for a solid phase extraction column to determine BPS in seven environmental samples using HPLC, achieving recovery of 89.20–105.78%. The developed MIL-101@MIP is a promising and efficient adsorbent for rapid and selective removal of BPS from the environment.

A two-stage sorption strategy to improve heat storage performance of salt/porous matrix composites

Composites combining salt hydrates and porous matrix like metal–organic frameworks (MOFs) are used to enhance the performance of thermochemical storage materials. However, the mechanism for the enhancement and the strategy for the selection of salt hydrates and porous matrix are not clear. The heat storage performance is determined by water adsorption dynamics, capacity and their sorption energy of the single components. The single components (salts or matrix) normally have either fast water adsorption dynamics or high-water uptake capacity, but not both of them. In this study, we investigate the enhancement of adsorption in composite materials, and a novel strategy is then proposed to combine the advantages from adsorbents with higher adsorption dynamics at low water partial pressure with those with a high capacity at high water partial pressure to promote the water adsorption capacity and kinetics, hence efficient energy storage. Two types of composites have been used to demonstrate the two-stage strategy developed in this study, in which SrCl2 and SrBr2 are incorporated into MOF MIL-101(Cr) to enhance adsorption and heat storage. In these composites, SrCl2 and SrBr2 can be regarded as the moisture pumps, capturing water vapour from air to improve the adsorption dynamics, while MIL-101(Cr) with high adsorption capacity functions as a water reservoir to take the water accumulated by the salts. Through this two-stage design, the water sorption capacity of the composites is 2–3 times higher than the water uptake of either salts or MOF within 120 min. As SrCl2 has a faster water adsorption kinetics than SrBr2, SrCl2/MIL-101(Cr) reaches an uptake of 0.73 g/g, however, the water sorption capacity of SrBr2/MIL-101(Cr) is 0.54 g/g. The composite samples also present good heat storage capacities of 1462 J/g for SrCl2/MIL-101(Cr) and 1526 J/g for SrBr2/MIL-101(Cr), and good cycling stability after 15 repeating adsorption/desorption cycles.

Synergistic ionic liquid encapsulated MIL-101 (Cr) metal-organic frameworks for an innovative adsorption desalination system

The transformations of brackish water into freshwater employing porous materials such as metal-organic frameworks (MOFs) show a great potential for a green environment. But the adsorption-based desalination slows down due to slow water adsorption/desorption rates and inadequate water storage capacity in conventional adsorbents. Therefore, the restructuring of porous MOFs increases water storage and transfer rates. This paper presents a comprehensive investigation on the fabrication of ionic liquid encapsulated MIL-101 (Cr) MOFs (metal-organic frameworks), and its interactions with water for desalination applications. Firstly, the pristine MIL-101 (Cr) is encapsulated with various types/amounts of ionic liquids. Next, these MOFs are characterized via SEM (Scanning electron microscope), FTIR (Fourier transform infrared), XRD (X-ray diffraction), TGA (Thermal gravimetric analysis), N2 adsorption techniques. The water adsorption on these MOFs is performed experimentally for a wide temperature (30–80 °C) and pressure (0 < P/Ps < 0.95) ranges. The effects of the size (or type) as well as the encapsulation ratio of ionic liquids on water adsorption behaviors are conducted. Based on the experimentally proven water adsorption (isotherms and kinetics) data, an AD (adsorption desalination) system is modelled and simulated. Finally, the AD performances in terms of the specific daily water production (SDWP) and performance ratio (PR) are parametrically studied with respect to various regeneration temperature (50–80 °C) and cycle times (100 s–1000 s). It is found that by ionic liquid encapsulation, the water uptakes/offtake rates are expedited up to 48% (for adsorption)/55% (for desorption), respectively. In addition, the water transfer (Δq) improves up to 45% more than the parent MIL-101(Cr) MOFs. Furthermore, the SDWP increases from 38 to 56 m3 of water per tonne of MOFs per day at the regeneration temperature of 70 °C. The simulation results also show that the ionic-liquid-encapsulated MIL-101 (Cr) MOFs generates water (>25 m3 water per tonne of IL-MOFs) at the regeneration temperature of 50 °C and is potential for the next generation desalination applications.

Synergistic effect of oxygen vacancies and functionalized ligands selectively enhanced the photocatalytic oxidation of methane to carbon monoxide

The titanium-based metal–organic framework MIL-125(Ti) has been widely investigated in photocatalytic carbon dioxide reduction and water splitting, but rarely studied in photocatalytic methane conversion by employing only water as an oxidant under mild conditions. Simultaneously controlling products with high yield and selectivity is highly challenging in methane conversion. Herein, we develop a series of functionalized titanium metal–organic frameworks via a facile organic ligand exchange process. The abundant Ti3+ active sites induced by oxygen vacancies and functionalized ligands synergistically facilitate the adsorption and activation of methane molecules. The carbon monoxide yield over NH2-MIL-125(Ti) increased to 198.6 μmol·gcat−1·h−1 with a high selectivity of 87.1 % under simulated solar illumination. Combined with in-situ characterizations and density functional theoretical calculations, the results confirmed that Ti3+ active sites induced by oxygen vacancies and amino functional groups synergistically enhanced the photocatalytic conversion of methane and elucidate CH4-to-CO conversion mechanism. This study does not only provide insights into the rational design of metal–organic frameworks with copious oxygen vacancies and functional groups, but also provides some significant cognition for photocatalytic methane conversion.

Non-steroidal anti-inflammatory drugs adsorption from aqueous solution by MOFs MIL-100(Fe), ZIF-8 and UiO-66: Synthesis, characterization, and comparative study

Pharmaceutical products such as ibuprofen and naproxen pose a potencial risk to the environment and to the human health. In this context, it is necessary seek and implement new effective and low-cost technologies for water treatment such as adsorption. Metal-organic frameworks (MOFs) emerge as promising adsorbent materials due to their structural diversity and stability. The obtained MOFs were characterized by SEM/EDX, XRD, FTIR, N2 at 77 K, DLS, and PZC. According to the textural parameters, the obtained MOFs have the next surface areas: MIL-100 (Fe) 1359 m2, ZIF-8 357 m2 and UiO-66 1654 m2. Having this differences in surface areas, alongside the different PZC of each materials, affect the adsorption capacity. According to the experimental data UiO-66 and MIL-100(Fe) had the highest ibuprofen adsorption capacity (152.3 mg g-1) and naproxen adsorption capacity (278.3 mg g-1), respectively. On the other hand, ZIF-8 has the lowest adsorption capacity of ibuprofen and naproxen (85.4 and 78.9 mg g-1 respectively). It was found that the best-fitting model according to its R2 for all materials with both adsorbates was the Sips model. Moreover, all materials with all adsorbates, except for UiO-66 with naproxen, reached equilibrium within the first 120 min and fitted the pseudo-second order model. According to thermodynamic parameters and analysis of fitted kinetic models, it was determined that during adsorption, a combination of physical and chemical phenomena occurs, from which the following interactions are proposed as the main adsorption mechanisms: hydrogen bonding, π -π interactions, anion-π interactions, and Lewis’ acid/base interactions.

Capturing low-concentration benzene: Design and mechanism of high-performance Cu1-Ox,Ny-C single-atom adsorbents

Common adsorbents, such as active carbons, zeolites, and metal–organic frameworks (MOFs), struggle to capture low concentrations of benzene. Single-atom adsorbents (SAAs), boasting exceptional atomic utilization efficiency and precisely tailored electronic structures, offer a promising solution. This study first designed Cu1-Ox,Ny-C SAAs and explored their enhanced benzene adsorption through density functional theory (DFT). Particularly, a crucial link between the SA coordination configuration and its affinity for benzene was established. Next, Cu1-Ox,Ny-C was synthesized from the MOF MIL-101(Cr) and extensively characterized using high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and X-ray absorption fine structure (XAFS) spectroscopy, etc. to determine the coordination configuration of Cu single atoms. Finally, a thorough evaluation of the Cu1-Ox,Ny-C’ capacity and stability was conducted. Theoretical analysis revealed that Cu single atoms within the Ox,Ny-C matrix act as the primary adsorption sites for benzene. Notably, O and N atoms work synergistically: oxygen atoms promote adsorption, while nitrogen atoms mainly stabilize single-atom sites. Cu1-Ox,Ny-C was successfully synthesized, and characterization revealed that Cu1-O2,N2(trans)-C and Cu1-O3,N1-C were the dominant coordination configurations. Remarkably, despite a fourfold decrease in specific surface area compared to MIL-101(Cr), Cu1-Ox,Ny-C exhibited a threefold increase in chemisorption capacity for low-concentration benzene. Moreover, it exhibits excellent resistance to H2O and can be effectively reused. This study demonstrates a valuable strategy for designing and creating highly efficient SAAs for capturing low concentrations of benzene.

Unraveling the toluene adsorption mechanism of MIL-101(Cr) derived from PET waste for COV removal applications

Herein, we provide a study on the removal of volatile organic compounds (VOCs) using a metal-organic framework MIL-101(Cr) derived from PET waste, denoted as MIL-101(Cr)-PET. As a model molecule for VOCs frequently found in indoor air, toluene was used. The characteristics and adsorption efficiency of both conventional MIL-101(Cr), denoted as MIL-101(Cr)-BDC, and environmentally friendly MIL-101(Cr) powders were evaluated and compared using a range of techniques in our research, including PXRD, HAADF-STEM, TGA, BET, and adsorption studies. MIL-101(Cr)-PET exhibits crystal structure and thermal stability similar to the conventional MIL-101(Cr) synthesized using a commercially available organic linker. Differently, it displayed relatively agglomerated smaller particles and a reduced surface area, attributed to the absence of any modulator and the use of PET waste as the source of the organic linker. Nevertheless, similar toluene adsorption performance was obtained in both batch and continuous adsorption setups. Furthermore, the adsorption mechanism was elucidated by means of molecular simulation, identifying two distinct adsorption sites. At low toluene concentrations, the preferred site was within the small cage due to pore size constraints, while at saturation, the most likely conformation involved parallel offset staking. These results suggest the occupancy of less energetically favorable sites and volumetric filling at higher concentrations.

Modulating cell stiffness for improved vascularization: leveraging the MIL-53(fe) for improved interaction of titanium implant and endothelial cell

Vascularization plays a significant role in promoting the expedited process of bone regeneration while also enhancing the stability and viability of artificial bone implants. Although titanium alloy scaffolds were designed to mimic the porous structure of human bone tissues to facilitate vascularization in bone repair, their biological inertness restricted their broader utilization. The unique attribute of Metal-organic framework (MOF) MIL-53(Fe), known as “breathing”, can facilitate the efficient adsorption of extracellular matrix proteins and thus provide the possibility for efficient interaction between scaffolds and cell adhesion molecules, which helps improve the bioactivity of the titanium alloy scaffolds. In this study, MIL-53(Fe) was synthesized in situ on the scaffold after hydrothermal treatment. The MIL-53(Fe) endowed the scaffold with superior protein absorption ability and preferable biocompatibility. The scaffolds have been shown to possess favorable osteogenesis and angiogenesis inducibility. It was indicated that MIL-53(Fe) modulated the mechanotransduction process of endothelial cells and induced increased cell stiffness by promoting the adsorption of adhesion-mediating extracellular matrix proteins to the scaffold, such as laminin, fibronectin, and perlecan et al., which contributed to the activation of the endothelial tip cell phenotype at sprouting angiogenesis. Therefore, this study effectively leveraged the intrinsic “breathing” properties of MIL-53 (Fe) to enhance the interaction between titanium alloy scaffolds and vascular endothelial cells, thereby facilitating the vascularization inducibility of the scaffold, particularly during the sprouting angiogenesis phase. This study indicates that MIL-53(Fe) coating represents a promising strategy to facilitate accelerated and sufficient vascularization and uncovers the scaffold-vessel interaction from a biomechanical perspective.Graphical

Dimensionality Control of Li Transport by MOFs Based Quasi‐Solid to Solid Electrolyte (Q‐SSEs) for Li−Metal Batteries

AbstractNowadays, lithium‐ion batteries (LIBs) are widely used in all walks of life and play a very important role. As complex systems composed of multiple materials with diverse chemical compositions, where different electrochemical reactions take place, battery interfaces are essential for determining the operation, performance, durability and safety of the battery. This work, set out to study the incorporation of lithium bis(fluorosulfonyl)amide (LiFSI) doped 1‐ethyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIm][TFSI]) ionic liquid into an archetype Ti‐based Metal Organic Framework (MOF) ((Ti) MIL125−NH2) to create a solid to quasi‐solid (depending on the amount of IL in the system), and how it affects not only ionic transport but also the structural properties of the IL/MOF electrolyte. Remarkably high ionic conductivity values (2.13×10−3 S ⋅ cm−1 at room temperature) as well as a lithium transference number (tLi=0.58) were achieved, supported by pulsed field gradient (PFG) NMR experiments. Electrochemical characterization revealed reversible plating‐stripping of lithium and lower overpotential after 750 h at 50 °C. Additionally, a proof‐of‐concept solid state battery was fabricated resulting in a discharge capacity of 160 mAh ⋅ g−1 at 50 °C and 0.1 C rate after 50 cycles. This work presents a suitable strategy to dendrite suppression capability, allowing its implementation as interface modifiers in next‐generation solid‐state batteries.

Molecularly imprinted polymer based on MIL-101 (Cr) MOF incorporated polyvinylidene for selective adsorption and separation dye with improved antifouling properties

In this work, new membrane was fabricated from polyester fabric (PF) as a substrate which was coated by a casting solution containing polyvinylidene fluoride (PVDF) blending by addition of MIL-101 (Cr) metal-organic framework (MOF)-molecularly imprinted 3-aminophenolhexamethylenetetramine (MIAPH) as filler and sodium dodecyl sulfate (SDS) as hydrophilic agent. The membrane was fabricated by phase inversion method (PVDF/MIAPH). The MIAPH has selective functional groups and was applied as filler in the mixed matrix membrane. The as-prepared MIAPH was characterized by FE-SEM, EDS, XRD, FTIR and BET-BJH analyses. The hydrophilic property, dye adsorption and filtration properties of the MIAPH/PVDF/PF membrane were studied for removal Trypan blue (TB) based on central composite design (CCD) technique through investigating operational variables (pH, TB concentration, pressure). In the fabrication of membranes, the optimal filtration properties appear at the 30 μL of SDS solution and 0.005 g MIAPH fillers. The fabricated MIAPH/PVDF/PF membrane indicates a high removal efficiency up to 94.9 % for the TB removal and has high selectivity. The data of the adsorption equilibrium were described by the Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherms. The findings illustrated that appropriate of MIAPH in membranes could be an efficient and selective technique for TB elimination.

First Direct Gravimetric Detection of Perfluorooctane Sulfonic Acid (PFOS) Water Contaminants, Combination with Electrical Measurements on the Same Device—Proof of Concepts

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are pollutants of concern due to their long-term persistence in the environment and human health effects. Among them, perfluorooctane sulfonic acid (PFOS) is very ubiquitous and dangerous for health. Currently, the detection levels required by the legislation can be achieved only with expensive laboratory equipment. Hence, there is a need for portable, in-field, and possibly real-time detection. Optical and electrochemical transduction mechanisms are mainly used for the chemical sensors. Here, we report the first gravimetric detection of small-sized molecules like PFOS (MW 500) dissolved in water. A 100 MHz quartz crystal microbalance (QCM) measured at the third harmonic and an even more sensitive 434 MHz two-port surface acoustic wave (SAW) resonator with gold electrodes were used as transducers. The PFOS selective sensing layer was prepared from the metal organic framework (MOF) MIL-101(Cr). Its nano-sized thickness and structure were optimized using the discreet Langmuir–Blodgett (LB) film deposition method. This is the first time that LB multilayers from bulk MOFs have been prepared. The measured frequency downshifts of around 220 kHz per 1 µmol/L of PFOS, a SAW resonator-loaded QL-factor above 2000, and reaction times in the minutes’ range are highly promising for an in-field sensor reaching the water safety directives. Additionally, we use the micrometer-sized interdigitated electrodes of the SAW resonator to strongly enhance the electrochemical impedance spectroscopy (EIS) of the PFOS contamination. Thus, for the first time, we combine the ultra-sensitive gravimetry of small molecules in a water environment with electrical measurements on a single device. This combination provides additional sensor selectivity. Control tests against a bare resonator and two similar compounds prove the concept’s viability. All measurements were performed with pocket-sized tablet-powered devices, thus making the system highly portable and field-deployable. While here we focus on one of the emerging water contaminants, this concept with a different selective coating can be used for other new contaminants.

Postsynthetic Modification of Amine-Functionalized MIL-101(Cr) Metal-Organic Frameworks with an EDTA-Zn(II) Complex as an Effective Heterogeneous Catalyst for Hantzsch Synthesis of Polyhydroquinolines.

The present work aims at preparing the EDTA-Zn(II) complex-supported on the amine-functionalized MIL-101(Cr) MOF-as a new and effective heterogenized catalyst. The optimization of the hydrothermal process shows that 120 °C is the best condition to grow the MIL-101(Cr)-NH2 MOF crystals. Moreover, regarding the use of the postsynthetic modification (PSM) method, hexadentate EDTA was grafted on this support via a simple aminolysis process before further coordinating it with Zn ions to create the corresponding Zn(II) catalytic complex. The catalytic activity of this compound was then investigated in the context of a one-pot synthesis of polyhydroquinolines. This approach has a number of advantages including the following: the use of a solvent that is not hazardous, applying a porous catalyst that is inexpensive, secure, and recyclable; rapid reaction times, high levels of efficiency, and the simplicity of MOF catalyst separation. Accordingly, the process in question can be given the label of "green chemistry".

Sustainable conversion of polyethylene plastic bottles into terephthalic acid, synthesis of coated MIL-101 metal–organic framework and catalytic degradation of pollutant dyes

Persistent environmental colored compounds, resistant to biodegradation, accumulate and harm eco-systems. Developing effective methods to break down these pollutants is crucial. This study introduces Ag-MIL-101 (Ag-MIL-101) as a composite and reusable catalyst that efficiently degrades specific colored organic pollutants (COPs) like Methylene blue (MB), 4-Nitrophenol (4-NP), and 4-Nitroaniline (4-NA) using sodium borohydride at room temperature. The MIL-101 was synthesized using Terephthalic acid (TPA) derived from the degradation of Polyethylene Terephthalate (PET) plastic waste, with the assistance of zinc chloride. To further investigation, the kinetics of degradation reaction was studied under optimized conditions in the presence of Ag-MIL-101 as catalyst. Our results demonstrated the remarkable efficiency of the degradation process, with over 93% degradation achieved within just 8 min. The catalyst was characterized using FTIR, XRD, FESEM, and TEM. In this study, the average particle size of Ag-MIL-101 was determined using SEM and XRD analysis. These methods allow us to accurately and precisely determine the particle size. We determined the reaction rate constants for the degradation of each COP using a pseudo first-order kinetic equation, with values of 0.585, 0.597 and 0.302 min−1 for MB, 4-NP, and 4-NA, respectively. We also evaluated the recyclability of the catalyst and found that it could be reused for up to three cycles with only a slight decrease in efficiency (10–15%). Overall, our findings highlight the promising application of Ag-MIL-101 as an effective catalyst for the degradation of COPs, emphasizing the importance of optimizing reaction conditions to achieve enhanced efficiency.

MIL-53(Al)–oil/water emulsion composite as an adjuvant promotes immune responses to an inactivated pseudorabies virus vaccine in mice and pigs

Although vaccination with inactivated vaccines is a popular preventive method against pseudorabies virus (PRV) infection, inactivated vaccines have poor protection efficiency because of their weak immunogenicity. The development of an effective adjuvant is urgently needed to improve the efficacy of inactivated PRV vaccines. In this study, a promising nanocomposite adjuvant named as MIL@A–SW01–C was developed by combining polyacrylic acid-coated metal–organic framework MIL-53(Al) (MIL@A) and squalene (oil)-in-water emulsion (SW01) and then mixing it with a carbomer solution. One part of the MIL@A was loaded onto the oil/water interface of SW01 emulsion via hydrophobic interaction and coordination, while another part was dispersed in the continuous water phase using carbomer. MIL@A–SW01–C showed good biocompatibility, high PRV (antigen)-loading capability, and sustained antigen release. Furthermore, the MIL@A–SW01–C adjuvanted PRV vaccine induced high specific serum antibody titers, increased splenocyte proliferation and cytokine secretion, and a more balanced Th1/Th2 immune response compared with commercial adjuvants, such as alum and biphasic 201. In the mouse challenge experiment, two- and one-shot vaccinations resulted in survival rates of 73.3 % and 86.7 %, respectively. After one-shot vaccination, the host animal pigs were also challenged with wild PRV. A protection rate of 100 % was achieved, which was much higher than that observed with commercial adjuvants. This study not only establishes the superiority of MIL@A–SW01–C composite nanoadjuvant for inactivated PRV vaccine in mice and pigs but also presents an effective method for developing promising nanoadjuvants. Statement of significanceWe have developed a nanocomposite of MIL-53(Al) and oil-in-water emulsion (MIL@A–SW01–C) as a promising adjuvant for the inactivated PRV vaccines. MIL@A–SW01–C has good biocompatibility, high PRV (antigen) loading capability, and prolonged antigen release. The developed nanoadjuvant induced much higher specific IgG antibody titers, increased splenocyte proliferation and cytokine secretion, and a more balanced Th1/Th2 immune response than commercial adjuvants alum and biphasic 201. In mouse challenge experiments, survival rates of 73.3 % and 86.7 % were achieved from two-shot and one-shot vaccinations, respectively. At the same time, a protection rate of 100 % was achieved with the host animal pigs challenged with wild PRV.

Nghiên cứu ảnh hưởng của công suất siêu âm đến đặc trưng tính chất của vật liệu khung cơ kim MIL-100

The metal-organic framework MIL-100 (Fe) was successfully synthesized using the ultrasonic method under different ultrasonic power. The as-synthesized materials were characterized by XRD, SEM, FT-IR and BET. The results showed that these materials have dimensions of a size range of 200-300 nm with similar morphology and structure. Among all the ultrasonic power studied, the material synthesized at ultrasonic power of 1080 W has the largest surface area of 1080.11 m2/g and reaction efficiency of 72.09%.

Synergistic enhancement of CO2 capture via amine decorated hierarchical MIL-101(Cr)/SBA-15 composites

Synthesis of amine incorporated hierarchical metal organic framework (MOF) MIL-101(Cr)/SBA-15, meso/micro-porous composites, with tailored properties for CO2 capture is reported. The synthesized composites were characterized in terms of their crystallinity, morphology, functional groups, and textural properties. Isothermal adsorption of CO2 from concentrated sites as well as ambient conditions were evaluated by gravimetric and volumetric measurements. The optimized composite i.e., MIL-101(Cr)/SBA-15/PEI-25 showed improved pseudo-equilibrium adsorption capacity of 3.2 mmol/g at 303 K and 1 bar, compared to nascent SBA-15 (0.8 mmol/g) and the MOF, i.e., MIL-101(Cr) (1.3 mmol/g). Such adsorption performance can be attributed to the basic sites of the impregnated polyethyleneimine (PEI), unsaturated Cr(III) metal sites, and the hierarchical pore structure of the composite which imparts chemical as well physical adsorption forces towards CO2 uptake. Interestingly, lower amine loading of 25 wt% in the composite resulted in facile CO2 desorption at much lower temperature of 65 °C. This guaranteed energy-efficiency and good reusability of the composite, after ten cycles, are evident from their structural and morphological studies.

Magnetic solid-phase extraction of tetracyclines from milk using metal-organic framework MIL-101(Cr)-NH2 functionalised hydrophilic magnetic nanoparticles

Novel metal-organic framework MIL-101(Cr)-NH2 functionalised hydrophilic polydopamine-modified Fe3O4 magnetic nanoparticles (Fe3O4@PDA@MIL-101(Cr)-NH2) were synthesised and used as magnetic solid-phase extraction (MSPE) adsorbents for extracting tetracyclines (TCs) from milk samples. The integrated Fe3O4@PDA@MIL-101(Cr)-NH2 exhibited convenient magnetic separation and exceptional multi-target binding capabilities. Furthermore, the PDA coating significantly enhanced the hydrophilicity and extraction efficiency of the material, thereby facilitating the extraction of trace TCs. Various factors affecting MSPE, such as adsorbent dosage, extraction time, pH value, and desorption conditions, were optimised. The developed MSPE method coupled with high-performance liquid chromatography demonstrated good linearity (R2 ≥ 0.9989), acceptable accuracy (82.2%–106.1%), good repeatability (intra-day precision of 0.8%–4.7% and inter-day precision of 1.1%–4.5%), low limits of detection (2.18–6.25 μg L−1), and low limits of quantification (6.54–18.75 μg L−1) in TCs detection. The approach was successfully used for the quantification of trace TCs in real milk samples.

Sustainable metal-organic framework based paper sheet as wallpaper for passive indoor moisture control

Passive indoor moisture control is a meaningful way to reduce HVAC operation and improve building energy efficiency. Metal-organic frameworks (MOFs) have been considered one of the most promising sorbent materials for passive indoor moisture control. However, the powder form of MOF is challenging to use in the built environment. Typical shaping methods like pellets, beads, and coating can lead to problems like partial pore blocking, insufficient mechanical stability, amorphization, and low material utilization. Here, we report a new sustainable MOF paper sheet comprising 25% cellulosic fibers and 75% MOF MIL-100(Fe) powder. The porous polymer matrix provides good support and fixation for MOF particles, so it’s more applicable in the built environment. The crystalline and pore structure characteristics of the MOF in the membrane are well preserved. Hydro characteristic test results show that MIL-100(Fe) paper sheet has high water vapor uptake, S-shape isotherm, mild regeneration condition, and high MBV. Then, a numerical model was developed to calculate the relation between a material’s MBV and its thickness. MIL-100(Fe) paper sheet with the most efficient thickness was applied as wallpaper in a building energy simulation model. The simulation result shows that the MIL-100(Fe) paper sheet is promising for passive indoor moisture control. It can remove about 45%-55% of the latent cooling load in most European climate types.

MOF-derived α-Fe2O3@Fe3O4 on carbon fiber fabric for lithium-ion anode applications

Owing to the current development in emerging fields as electric motoring, biomedical sensors or new generation of mobile phones, new functionalities are required for the new generation of Li-ion batteries as flexibility or structurality. Thus, Metal-Organic Framework (MOF)-derived α-Fe2O3@Fe3O4 coating on carbon fiber fabric has been developed in this study for Lithium-ion battery anode purposes. MOF-derived synthesis is a well-known strategy to obtain Transition Metal Oxides (TMOs) which better electrochemical performance than bare TMOs. On the other hand, synthesis on carbon fiber fabric allows to develop new electrodes for multifunctional energy storage devices in which the coating provides high specific capacity, while the carbon fiber substrate provides stiffness but high flexibility, mechanical strength, and electrical conductivity. This TMO coating was achieved by a novel MOF MIL-100 direct synthesis on carbon fiber and subsequent calcination, the effects of calcination on the composition, texture and morphology of the coating, as well as its electrochemical performance, were studied. As the best result, calcinated samples during 2 h showed the optimal synergic effects between the coating and carbon fiber, exhibiting a specific capacity of 328.6 mAh/g at 25 mA/g, an excellent rate capability and a capacity retention of 89.7 % after 100 galvanostatic charge-discharge cycles. Nevertheless, it is important to note that the novelty of this work is not only based on the electrochemical performance but also on the novel synthesis of MIL-100 directly over the carbon fibers. This novel synthesis opens the way to new variety of TMO coatings for electrodes of all-solid-state energy storage devices.

Enhancing the photoelectric performance of TiO2-based heterojunction using the hydrothermal decomposition of MIL-125 strategy for sensitive detection of Bisphenol A

Due to its outstanding conductive properties, TiO2-based heterojunctions have extensive applications in the field of photoelectrochemical sensors. However, due to surface energy and van der Waals forces, TiO2 tends to aggregate and presents an uneven distribution, which reduces the overall performance of these heterostructures. To overcome these challenges and achieve a uniform distribution of TiO2 within the heterojunction, the characteristic of gradual decomposition of the metal-organic framework MIL-125 under hydrothermal conditions was employed. This process gradually generates TiO2 particles that slowly participate in the construction of the heterojunction. By combining the exceptional light absorption properties and appropriate bandgap widths of CdS and CdIn2S4, a uniformly distributed flower-globular ternary heterojunction CdS/CdIn2S4/TiO2-FG was successfully synthesized. In comparison to the disordered heterojunction CdS/CdIn2S4/TiO2-DO, CdS/CdIn2S4/TiO2-FG exhibits enhanced visible light absorption properties and photoelectric conversion efficiency. Taking Bisphenol A (BPA) as a model, a signal-off photoelectrochemical (PEC) aptasensor based on the CdS/CdIn2S4/TiO2-FG was established and exhibited a high sensitive detection for BPA with a linear response range from 10−1 to 107 pM, as well as an ultralow detection limit of 0.015 pM, revealing vivid selectivity, stability, and reproducibility. Therefore, this study offers an efficient and straightforward approach for the preparation of TiO2-based heterojunctions with superior photoelectric activity.