Aluminum-based Metal Organic Framework Research Articles

A β-ray irradiation resistant MOF-based trap for efficient capture of Th(IV) ion

Efficient capture of radionuclides from aqueous solution is highly essential for environment safety and resource recycling, but still faces large challenge. In this study, a stable aluminum-based metal–organic framework (MOF-303) with high-density ion traps was used to selectively capture thorium (Th) ion from aqueous solution. The features of aluminum center endow this material with excellent resistance from β-ray irradiation even with a high dose of 1000 kGy. Further, due to the special chelation interaction from the ion trap, MOF-303 exhibits a large adsorption capacity for Th(IV) ion (461.7 mg g−1) and excellent separation coefficients up to 97.6, 97.3 and 81.3 for Th(IV)/Pr(III), Th(IV)/Eu(III) and Th(IV)/Nd(III) respectively. The adsorption equilibrium was reached at ∼ 420 min. Besides, the regeneration of MOF-303 as well as the elution of Th(IV) ion can be achieved via an acid-wash process. Experimental and theoretical calculation results indicate Th(IV) ion can be tightly anchored in the ion trap surrounded by six active atoms, via the chemical bonding mode.

Conformational fixation induced fluorescence turn-on of oxytetracycline coordinated on aluminum-based metal-organic frameworks for ultrasensitive sensing application

Since the abuse of oxytetracycline (OTC) has brought serious environmental problems, it is of great practical significance to develop sensitive OTC fluorescent probes to quantify environmental OTC residues. Herein, the aluminum-based metal-organic framework MIL-53(Al) with microflower morphology and plentiful surface open aluminum sites (denoted as FMIL-53(Al)) was tailored via an acetic acid-assisted solvothermal method and subsequently exploited for ultrasensitive detection of OTC. Compared with conventional hydrothermally synthesized MIL-53(Al), FMIL-53(Al) possesses a larger specific surface with plentiful open aluminum sites, which can selectively coordinate with OTC to fix the molecular conformation. The coordinated OTC molecules undergo a transition from twisted-conformation to extended-conformation, accompanied by an increase in fluorescence quantum yield. As a fluorescent probe, the detection limit of FMIL-53(Al) for OTC is estimated as low as 0.94 nM. Finally, the FMIL-53(Al)-based probe can be applied for the detection of OTC in water samples of fish farm pond, and a portable test paper was successfully fabricated for on-site visual identification of OTC. This work not only demonstrates a novel morphology of MIL-53(Al) for OTC ultrasensitive sensing but also provides an example of morphological engineering to optimize the performance of MOF-based fluorescence sensors.

Simultaneous preconcentration and pre-column derivatization for rapid analysis of nitrilotriacetic acid in environmental waters by high performance liquid chromatography

A simplified sample pretreatment procedure was developed for quantitative measurement of nitrilotriacetic acid (NTA) in environmental water. On the basis of coordination capacity between NTA and metal ions, aluminum-based metal organic framework (MOF, MIL-53(Al)) was adopted for the adsorption of NTA, followed by stripping with copper sulfate as the eluent. The adsorbed NTA was converted into Cu-NTA during the desorption process, which facilitated the ensuing measurement by high performance liquid chromatography (HPLC). A linear range within 0.10 - 10 mg L−1 was achieved, along with a limit of detection (LOD, S/N=3, n=7) of 0.03 mg L−1 and an enrichment factor of 10.4. The developed method was validated by the analysis of sea water, influent of wastewater treatment plant and industrial wastewater, with satisfactory recoveries (90.2 - 91.1%) obtained.

Surface hydration of fibrous filters by using water-absorbing metal–organic frameworks for efficient ultrafine particulate matter removal

Air pollution, particularly from particulate matters (PMs), has become a serious global issue. Thus, there are increasing demands for improving PM filtering systems for public safety. Here, we have first demonstrated that the surface hydration of electrospun fiber-based filters significantly improves capturing ability of ultrafine PM0.3 (PMs having a diameter of ∼ 0.3 µm). Aluminum-based metal–organic framework (MOF)–303, which is uniformly coated on the surface of polyimide nanofibers (PI NFs), provides sufficient surface hydration with PI NFs due to its high-water uptake capability, resulting in favorable trapping sites for polar molecules or particles in the air. Furthermore, the MOF–303-coated PI NF (PI@MOF–303) filters show relatively low pressure drops, which can be attributed to increasing fiber diameters after MOF–303 coating, resulting from enlarged spaces between fibers. Consequently, the PI@MOF–303 filters afford highly efficient PM0.3 removal properties (95.70%) and low pressure drop (ΔP = 36.73 Pa). Our strategy offers new insights into the fabrication of high-performance electrospun fiber-based filters with desirable properties for filtering PMs.

Porous Aluminum-Based Metal-Organic Framework-Aminoclay Nanocomposite: Sustainable Synthesis and Ultrahigh Sorption of Cephalosporin Antibiotics.

A novel sorbent was synthesized based on MIL-53(Al) MOF grown over an aminoclay (AC) platform, called MIL-53(Al)@AC nanocomposite, via a green and facile hydrothermal method. The nanocomposite was characterized using FT-IR, PXRD, BET, TEM, FESEM, EDS, XPS, TGA, DLS, and zeta potential analyses. BET analysis represented the porous nature and great surface area of MIL-53(Al)@AC. The high crystalline structure for the synthesized nanocomposite was verified using the PXRD pattern. FESEM, EDS, TEM, and XPS analysis proved the successful decoration of MIL-53(Al) over the AC platform. Cephalosporin antibiotics cefixime (CFX) and cephalexin (CPX), which are often present in wastewaters, were utilized to examine the sorption capacity of the nanocomposite. The significant influential factors such as pH, temperature, sorbent amount, ionic strength, and impurity were discussed. At an initial pH of 7.0 ± 0.1, the highest sorption capacities of CFX and CPX on MIL-53(Al)@AC were 784.14 and 747.91 mg g-1 (T = 298 K, and sorbent amount = 0.1 g L-1), which were 1.43 and 1.47 times greater compared to that of MIL-53(Al), respectively. The evaluation of experimental results was implemented through the Langmuir and Freundlich isotherm equations. The isothermal data were described nobly by the Freundlich isotherm, which confirmed multilayer adsorption on heterogeneous surfaces (R2 > 0.970). A kinetic study indicated that the nanocomposite could adsorb the majority of cephalosporin antibiotics within 30 min. In addition, the experimental data were evaluated via pseudo-first-order, pseudo-second-order, and intraparticle diffusion models. The results indicated that the pseudo-second-order equation agreed more closely with the kinetic data (R2 > 0.990). Furthermore, the processes of adsorption were exothermic and spontaneous. The electrostatic attraction, hydrophobic interaction, π-π electron donor-acceptor effect, H-bond, and π-π stacking constituted the main sorption mechanisms. Finally, MIL-53(Al)@AC presented an excellent regeneration performance. Thus, the results revealed the potential application of the MIL-53(Al)@AC nanocomposite for water remediation.

Constructing Graphene-Wrapped Octahedron Aluminum-Based Metal Organic Framework Anchored PdSnBi Nanoparticles for Boosting Ethylene Glycol Electrooxidation

Constructing Graphene-Wrapped Octahedron Aluminum-Based Metal Organic Framework Anchored PdSnBi Nanoparticles for Boosting Ethylene Glycol Electrooxidation

MOF@chitosan Composites with Potential Antifouling Properties for Open-Environment Applications of Metal-Organic Frameworks

Metal-organic frameworks (MOFs) are promising materials for a myriad of applications because of their easy synthesis and large variability through the organic linker. For open-environment applications, the organic content can, however, give rise to fouling, that is, biofilm formation. Biofilms can destroy the MOF and reduce the sorption capacity. Therefore, it is necessary to formulate MOFs for open-environment application to avoid the growth of microorganisms. Chitosan is a polysaccharide biopolymer, obtained from chitin shells of shrimps by alkaline deacetylation, and has known fungistatic properties. Here, chitosan is used as a matrix for MOF@chitosan composites with different aluminum-based MOFs to implement the fungistatic effect of chitosan to MOFs. The obtained composites with the highest possible MOF loadings of up to 90% were tested according to DIN EN ISO 846 to examine the fungistatic material properties against the fungi Chaetomium globosum and Aspergillus falconensis.

Enhancing CH4/N2 separation performance within aluminum-based Metal-Organic Frameworks: Influence of the pore structure and linker polarity

Efficient CH4/N2 separation is necessitated for obtaining purified methane from natural gas. Aluminum-based metal–organic frameworks (Al-MOFs) have potential for industrial separation applications due to their structure-tunable, low-cost, and scalable features. Intrigued by the impressive selectivity of a recently reported Al-MOF (Al-CDC) toward CH4 over N2, we herein further study the potential of Al-MOFs as adsorbent for CH4/N2 separation, mainly considering the effects of pore geometry and linker polarity. Utilization of two bent ligands and two linear ligands with different polarity afforded two one-dimensional square-shaped Al-MOFs i.e., CAU-10-H, MIL-160, and two rhombic-shaped counterparts i.e., Al-Fumarate (Al-Fum), MIL-53(Al)), respectively. Afterward, pure CH4 and N2 adsorption experiments were conducted at 273–313 K for assessing the CH4/N2 separation performance. The results indicated that all the Al-MOFs exhibited superior affinity toward CH4 over N2, and the CH4 uptake followed the sequence of Al-Fum > CAU-10-H > MIL-53(Al) > MIL-160. Exhilaratingly, Al-Fum exhibited unprecedented CH4/N2 selectivity (17.2) and high CH4 uptake at 273 K and 1.0 bar. The mechanism underlying the disparity of Al-MOFs affinity toward CH4 was deciphered via theoretical simulation, suggesting that the synergetic effects of accessibility of strong affinity sites (μ2-OH) on AlO6 chains and polar pore surface induced by varying linkers highly promoted the CH4 uptake. Furthermore, the results of cyclic adsorption–desorption experiments and binary breakthrough tests validated the feasibility of Al-Fum for practical application.

Lewis acid-triggered photocatalytic hydrogen peroxide production in an aluminum-based metal-organic framework.

Al-MIL-101-NH2, which was previously regarded as being inactive as a photocatalyst, produces hydrogen peroxide (H2O2) via O2 reduction under visible-light irradiation, accompanied by efficient suppression of undesired H2O2 decomposition. The low-coordination Lewis acid sites in trimetric Al-oxo clusters are crucial for the electron transfer to O2.

Highly sensitive electrochemical detection of myricetin in food samples based on the enhancement effect of Al-MOFs.

Microporous aluminum-based metal-organic frameworks (CAU-1) are used to develop a simple and sensitive electrochemical sensor for myricetin (MYR) based on a modified carbon paste electrode (CPE) for the first time. The morphologies and electrochemical properties of the as-synthesized CAU-1 are studied utilizing various analytical methods including scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, N2 adsorption-desorption, and electrochemical impedance spectroscopy. In terms of electrochemical oxidation of MYR, CAU-1/CPE with its large number of active micropores and rapid electron transfer demonstrates superior performance compared to the bare CPE. Under optimized conditions, the calibration curve for MYR exhibits a linear range of 1.0-10 μg L-1 and 10-1000 μg L-1 with a detection limit of 0.50 μg L-1. The developed CAU-1/CPE exhibits superior analytical characteristics, compared to previously reported electrochemical sensors for MYR detection. Furthermore, CAU-1/CPE is employed to determine MYR in Myrica bark samples, and the results are consistent with those obtained by high-performance liquid chromatography, demonstrating the excellent potential of CAU-1/CPE for the rapid analysis of MYR in complicated real samples.

Green Preparation of Aluminum-based Metal-organic Framework (Al-MOF) from Waste Plastic Bottles and Waste Aluminum Scraps

The vast use of polyethylene terephthalate (PET) drinking water bottles has increased dramatically worldwide in recent decades, inflicting severe consequences on the environment. According to the latest survey, a million plastic bottles are bought around the globe every minute. The non-biodegradable nature of PET materials has led to a huge accumulation of plastic in waste landfills. Among the current recycling methods used to solve this environmental problem is chemical recycling. In this method, PET bottles are converted back cleanly into their starting materials: terephthalic acid and ethylene glycol. This paper unveils the exploitation of recycling products from PET bottles and aluminium scraps in order to prepare a metal-organic framework (MOF) material. The characterization of the prepared MOF substance was carried out using different techniques such as IR, XRD, SEM and elemental analysis.

Selective Adsorption and Separation of o-Xylene Using an Aluminum-Based Metal–Organic Framework

Selective Adsorption and Separation of <i>o</i>-Xylene Using an Aluminum-Based Metal–Organic Framework

Metal organic frameworks as platforms for the nanostructuring of Mn3 single molecule magnets

In this paper, we report incorporation of the nanostructuration Single-Molecule Magnets (SMMs) Mn3 into mesoporous aluminum-based metal-organic framework (MOF) [Al(OH)(SDC)]n (H2SDC ​= ​4,4′-stilbenedicarboxylic acid), known as CYCU-3. The successful incorporation was confirmed by PXRD, N2 adsorption measurements and thermogravimetric analysis. EDX analysis indicated average 15 ​mol% insertion of SMMs, which is substantial higher than what was previously reported for SMM@silica composites. TGA measurements suggest that MOF can increase the SMM's thermal stability. Magnetic measurements reveal the preservation of the magnetic properties of SMMs inside MOF pores. The AC susceptibility data suggest an effective energy barrier of about 40 ​K for SMM@MOFs composites, slightly lower than those of pristine Mn3 SMMs, which is about 55 ​K.

Enhanced Fungicidal Efficacy by Co-Delivery of Azoxystrobin and Diniconazole with Cauliflower-Like Metal-Organic Frameworks NH2-Al-MIL-101.

Long-term use of a single fungicide increases the resistance risk and causes adverse effects on natural ecosystems. Controlled release formulations of dual fungicides with different modes of action can afford a new dimension for addressing the current issues. Based on adjustable aperture and superhigh surface area, metal–organic frameworks (MOFs) are ideal candidates as pesticide release carriers. This study used Al3+ as the metal node and 2-aminoterephthalic acid as the organic chain to prepare aluminum-based metal–organic framework material (NH2-Al-MIL-101) with “cauliflower-like” structure and high surface area of 2359.0 m2/g. Fungicides of azoxystrobin (AZOX) and diniconazole (Dini) were simultaneously encapsulated into NH2-Al-MIL-101 with the loading content of 6.71% and 29.72%, respectively. Dual fungicide delivery system of AZOX@Dini@NH2-Al-MIL-101 demonstrated sustained and pH responsive release profiles. When the maximum cumulative release rate of AZOX and Dini both reached about 90%, the release time was 46 and 136 h, respectively. Furthermore, EC50 values as well as the percentage of inhibition revealed that AZOX@Dini@NH2-Al-MIL-101 had enhanced germicidal efficacy against rice sheath blight (Rhizoctonia solani), evidenced by the synergistic ratio of 1.83. The present study demonstrates a potential application prospect in sustainable plant protection through co-delivery fungicides with MOFs as a platform.

Transformation of Al-CDC from 3D crystals to 2D nanosheets in macroporous polyacrylates with enhanced CH4/N2 separation efficiency and stability

Development of materials with high efficiency and long-life cycles for CH4/N2 separation is of importance for coal-bed methane purification. Herein, a composite was prepared by in-situ growing the specific aluminum-based metal–organic framework (MOF) with trans-1,4-cyclohexanedicarboxylicacid as ligand (Al-CDC) on the internal macroporous surface of polyacrylates (PA). Due to the surface-induced low-energy-barrier orientation crystallization, the morphology of Al-CDC was transformed from three-dimensional (3D) crystals to two-dimensional (2D) nanosheets, forming ultrathin films with higher adsorption efficiency and lower diffusion barrier. As a result, the adsorption efficiency can be increased by 1.73 times compared with bulk Al-CDC and the selectivity of CH4/N2 (50/50, v/v) mixed gas is 13.75, which is the highest value reported so far. Furthermore, the hydrophobic feature of PA enhanced the water and recycling stability of composite, providing promising adsorbent for coal-bed methane purification using pressure swing adsorption process.

Synthesis and Sulfonation of an Aluminum-Based Metal–Organic Framework with Microwave Method and Using for the Esterification of Oleic Acid

Synthesis and Sulfonation of an Aluminum-Based Metal–Organic Framework with Microwave Method and Using for the Esterification of Oleic Acid

Solvent-Free and Phase-Selective Synthesis of Aluminum Trimesate Metal-Organic Frameworks.

Aluminum-based metal-organic frameworks (Al-MOFs) have shown promise as commercially valuable materials due to the variety of applications, excellent thermal, hydrothermal, and chemical stabilities, and the abundance of aluminum. In this work, for the first time, we report the solvent-free synthesis of the aluminum trimesate (Al-BTC) MOFs (MIL-100(Al), MIL-96(Al), and MIL-110(Al)) with phase selectivity and high yield. These MOFs were traditionally prepared with HF, HNO3, and bulk solvents, but these methods struggled to produce pure-phase isolations. The solvent-free strategy provides valuable insight into the future industrial scale-up production of the Al-MOFs and promotes the potential commercialization of such materials.

Correction to: Structural similarity, synthesis, and adsorption properties of aluminum-based metal-organic frameworks

It has come to our attention that the following sentence contains an error: “However, while the octahedra in MIL-53 are cis-connected, the octahedra in CAU-10 are trans-connected.” The words “cis” and “trans” should be swapped to read “However, while the octahedra in MIL-53 are trans-connected, the octahedra in CAU-10 are cis-connected.”

Structural similarity, synthesis, and adsorption properties of aluminum-based metal-organic frameworks

Structural similarity, synthesis, and adsorption properties of aluminum-based metal-organic frameworks

Tuning microscopic structure of Al-based metal-organic frameworks by changing organic linkers for efficient phosphorus removal

In this study, five aluminum-based metal-organic frameworks ( i.e. Al-BDC, Al-BDC-NH 2 , Al-BHTA, Al-PMA and Al-BPDC) were synthesized by changing the organic linker. Among the five Al-MOFs, Al-BDC, which used 1,4-benzenedicarboxylate as a linker, showed the highest phosphorus adsorption capacity (97.50 mg P/g), while Al-PMA, which used 1,2,4,5-benzenetetracarboxylic acid as a linker, exhibited the lowest phosphorous adsorption capacity (42.25 mg P/g). The adsorption capacity was higher than most adsorbents reported in the literature. In addition, Al-PMA and Al-BPDC are more cost-effective for removing low concentrations of phosphorous from water. When the aqueous phosphorus concentration was less than 1.0 mg P/L, and the dosage of the five Al-MOFs was only 0.10 g/L, more than 90% of phosphorus was removed. The Al-MOFs are suitable for phosphorus removal from water over a wide pH range (5.0–9.0). In this pH range, almost no Al was detected in water after phosphorus removal, indicating that the Al-MOFs can remove phosphorus from water without causing secondary pollution. Moreover, in a NaCl (0.01 mol/L) background electrolyte solution, the Al-MOFs showed high phosphorus removal stability. The Al-MOFs have the potential to remove phosphorus from natural water. Furthermore, the mechanism study shows that electrostatic interaction and ligand exchange were defined as the main phosphorus removal pathways using the prepared Al-MOFs. These findings demonstrate that the synthesized Al-MOFs are promising candidates for removal of phosphorus from eutrophic water. • The microscopic structures of Al-MOFs were tuned with different organic linkers. • Surface area and pore structure of MOFs significantly affect the phosphorus adsorption performance. • Al-BDC shows high adsorption capacity of 97.50 mg P/g for phosphorus. • Excellent phosphorus removal efficiency was obtained in real water. • Electrostatic interaction and ligand exchange are responsible for the adsorption mechanism.