Organic Frame Research Articles

Porous Organic Frame Materials for Adsorption and Removal of Pesticide Contaminants: A Review

Porous Organic Frame Materials for Adsorption and Removal of Pesticide Contaminants: A Review

Visual Detection of Dopamine with CdS/ZnS Quantum Dots Bearing by ZIF-8 and Nanofiber Membranes.

Dopamine (DA) is a widely present, calcium cholinergic neurotransmitter in the body, playing important roles in the central nervous system and cardiovascular system. Developing fast and sensitive DA detection methods is of great significance. Fluorescence-based methods have attracted much attention due to their advantages of easy operation, a fast response speed, and high sensitivity. This study prepared hydrophilic and high-performance CdS/ZnS quantum dots (QDs) for DA detection. The waterborne CdS/ZnS QDs were synthesized in one step using the amphiphilic polymer PEI-g-C14, obtained by grafting tetradecane (C14) to polyethyleneimine (PEI), as a template. The polyacrylonitrile nanofiber membrane (PAN-NFM) was prepared by electrospinning (e-spinning), and a metal organic frame (ZIF-8) was deposited in situ on the surface of the PAN-NFM. The CdS/ZnS QDs were loaded onto this substrate (ZIF-8@PAN-NFM). The results showed that after the deposition of ZIF-8, the water contact angle of the hydrophobic PAN-NFM decreased to within 40°. The nanofiber membrane loaded with QDs also exhibited significant changes in fluorescence in the presence of DA at different concentrations, which could be applied as a fast detection method of DA with high sensitivity. Meanwhile, the fluorescence on this PAN-NFM could be visually observed as it transitioned from a blue-green color to colorless, making it suitable for the real-time detection of DA.

Copper/ cerium metal organic frame work as highly efficient structures for solar power-induced hydrogen generation through the process of water splitting

Increased dependence on fossil fuels as energy sources strongly contributes in both global warming and environmental pollution, leading to serious impacts on human-beings and societies. Therefore, shift from hydrocarbon-based energy to alternative green, sustainable and renewable sources of energy has been globally stimulated in past decades. In an agreement with this context, hydrogen is counted as one of these sources which has been paid strong attention recently due to its high energy content and no harmful emissions. Consequently, this study introduces production of clean green hydrogen through the process of photocatalytic water splitting which is a cost-effective route and releases zero emissions. A series of copper/ or cerium based metal–organic frameworks were successfully prepared via one-pot solvothermal technique and were presented as three novel photocatalysts for hydrogen production from water. The photocatalytic performances of these structures were investigated under visible light irradiation, revealing the highest activity for copper doped cerium metal–organic framework. It exhibited a maximum pure hydrogen productivity of 465 mmol per hour/ gram which was much higher than those the detected productivity by copper and cerium metal–organic frameworks (289 and 375 mmol per hour/ gram respectively). Heterojunction between the two central metals as well as effective charge separation in copper doped cerium metal–organic framework are reasons of its superiority in hydrogen evolution exploit, compared to the other two structures. The recyclability of copper doped cerium metal–organic framework demonstrated high reliability since it showed nearly stable yields of hydrogen over ten cycles of photocatalytic reuse. Therefore, the presented binary metals organic framework establishes new platform for photocatalysts in process of hydrogen production through water splitting.

Magnetic modification of cerium organic frame materials to improve the phosphorus adsorption performance: Modulating the valence state

Excessive phosphate levels in water bodies can lead to eutrophication, one of persistent environmental pollution problems. Metal-organic frameworks (MOFs) have garnered significant attention as a promising material for phosphorus removal due to their high capacity. However, there are challenges with solid-liquid separation necessitating magnetic modification solutions. The low adsorption capacity of magnetite (Fe3O4) for phosphates has a potential negative impact on magnetic composites. To explore solutions that enable magnetic modification without reducing the adsorption capacity, Ce-MOFs@Fe3O4 were successfully prepared. Experimental results showed an increase in adsorption capacity and removal rate post magnetic modification, with the phosphorus saturation adsorption capacity reaching 156.01 mg·g−1. Further investigations involving the adsorbent dosing, co-existence of ions, and stability tests were conducted to explore the practical applications. The results indicated that Ce-MOFs@Fe3O4 performed well across a wide pH range from 4 to 10 and exhibited excellent selectivity in the presence of SO42-, Cl-, and NO3-. Zeta potential, FT-IR, and XPS analysis revealed electrostatic attraction and ligand exchange as the main adsorption mechanisms. Ce (III) species played a crucial role in phosphate binding by forming insoluble CePO4. On the contrary, Ce (IV) is not helpful for phosphate removal due to insufficient coordination number. In this study, adding Fe3O4 during synthesis facilitated a substantial increase in Ce (III) content, which enhanced the phosphate adsorption capacity and imparted magnetic properties. Hence, the proposed preparation method could serve as a general magnetic strategy for Ce-based adsorbents, enhancing the phosphorus adsorption capacity.

Direct modification of pelletized 13X zeolite by atomic layer deposition toward effective CO2 capture from flue gas

As a promising sorbent material for post combustion CO2 capture, 13X zeolite has been broadly investigated in pressure/vacuum swing adsorption (P/VSA). However, recent P/VSA process simulation studies have posited that some metal organic frame works (MOFs) with reduced CO2 and N2 adsorption affinities and adsorption enthalpies can enable process level improvements, suggesting that the CO2/N2 adsorption strength in 13X may be stronger than what is optimal for post combustion CO2 capture (PCC) via P/VSA. Via preferential H2O adsorption on strong adsorption sites in 13X zeolite, we found that temporarily passivating these sites led to enhancements in CO2 working capacity (5–15 kPa CO2, 30 °C) and CO2/N2 separation factor (5–15 kPa CO2, 1–85 kPa N2, 30 °C) by 12 % and 94 %, respectively. To permanently weaken the adsorption strength in 13X, we employed H2O/TiCl4 atomic layer deposition (ALD) to “passivate” the strong adsorption sites and thus fabricate a novel adsorbent, Ti-13X, and investigated the effect of selective inhibition of high adsorption strength sites on the thermodynamic CO2/N2 adsorption properties. The modification technique resulted in suppressed CO2 and N2 adsorption affinity, manifesting in a 10 % and 133 % increase in the CO2 working capacity (5–15 kPa, 30 °C) and CO2/N2 separation factor (5–15 kPa CO2, 1–85 kPa N2, 30 °C), respectively. CO2 microcalorimetry experiments showed a suppressed and homogenized CO2 heat of adsorption in Ti-13X versus pristine 13X, indicating that high enthalpy CO2 adsorption was inhibited while the CO2 physisorption behavior was preserved. When evaluated using the General Evaluation Metric (GEM), Ti-13X scored similarly to promising MOFs and significantly outscored pristine 13X, suggesting its merit for future investigation.

Preparation of KH560‐UiO‐66‐NH2/Pebax mixed matrix membranes and CO2 separation

AbstractMetal–organic frame UiO‐66‐NH2 was modified by 3‐glycidyl ether oxypropyl trimethoxysilane (KH560), and KH560‐UiO‐66‐NH2 was synthetized and added to Pebax to prepare KH560‐UiO‐66‐NH2/Pebax mixed matrix membranes (MMMs). The epoxy group of KH560 had an amine‐epoxidation reaction with the NH2 in UiO‐66‐NH2, which prevented UiO‐66‐NH2 from agglutinating in the MMMs. In addition, the NH bond and OH bond of KH560‐UiO‐66‐NH2 could theoretically form hydrogen bonds with CO and NH bonds in the main chain of polymerization, respectively, so as to improve the interfacial compatibility between fillers and polymers. The structure and properties of the filler particles and MMMs were evaluated by Fourier transform infrared spectrometer, x‐ray diffraction, scanning electron microscopy, and thermogravimetric analyzer. The results showed that the filler particles were successfully synthesized, and had good crystallinity, uniform size distribution, and good thermal stability. The inorganic and organic interfaces of MMMs had no obvious interface defects. The obtained KH560‐UiO‐66‐NH2/Pebax MMMs showed CO2 permeability of 111.52 Barre and CO2/N2 selectivity of 92.16, which were 85.65% and 88.73% higher than that of pristine membranes, respectively. The gas separation performance of MMMs was significantly improved, exceeding the upper bound of 2008 Robeson.

The influence of organic molecular rotation on carrier Dynamics: A case of MAPbI3

At room temperature, organic molecules undergo continuous rotation, driven by rotational barriers lower than kBT. However, consensus regarding the impact of organic molecule rotation on carrier dynamics remains elusive, as conventional research methods struggle to distinguish between organic molecule rotation and inorganic frame vibrations. This study successfully achieved the goal of modulating the rotation rate of organic molecules by adjusting the relative atomic mass of nitrogen atoms. In the investigation of carrier dynamics, the rotational rate of organic molecules served as the sole independent variable. The findings indicate that a slower rotation rate correlates with an extended carrier lifetime. This correlation is attributed to the heightened charge separation and reduced motion of nuclei. This research provides valuable insights for prolonging the carrier lifetime of organic–inorganic hybrid perovskites.

Controlled release of phosphorus-containing free radical from the porous channels of metal–organic frame to reduce the combustion heat and smoke releases of polystyrene

Controlled release of phosphorus-containing free radical from the porous channels of metal–organic frame to reduce the combustion heat and smoke releases of polystyrene

Investigation of tribological behavior of MOFs/g-C3N4 nanocomposite for insight into effect of flake-on-sheet and ball-on-sheet nanostructure

Herein, we designed two catalogs of metal organic frame materials (MOF)/carbon nitride(g-C3N4) composite nanostructures (flake-on-sheet and ball-on-sheet nanostructure appearances) to probe the effect of composite nanostructures on the cooperative friction mechanism. The tribological behaviors of MOF/g-C3N4 composite nanostructures were extensively investigated in base oil on the four-ball friction tester. The results showed that the anti-wear ability of flake-on-sheet shaped MOF/g-C3N4 in oil was superior to the ball-on-sheet shaped MOF/g-C3N4, whereas the anti-friction and load-bearing ability of latter was preferable to the former. The flake-on-sheet shaped MOF/g-C3N4 enabled the friction coefficient (COF) and wear scar diameter (WSD) of oil to reduce 31.90% and 45.46%, while the ball-on-sheet shaped MOF/g-C3N4 enabled the friction coefficient (COF) and wear scar diameter (WSD) of oil to decrease 37.07% and 42.15%, respectively. Due to the morphology difference, the anti-frition and anti-wear mechanism of the flake-on-sheet shaped MOF/g-C3N4 were reliable to the tribo-film consisting of adsorption film and tribochemical film, whereas that of ball-on-sheet shaped MOF/g-C3N4 depended on the synergistic effect of the tribo-film and the ball bearing effect of MOF nanospehere in composite structure. Moreover, the interface interaction in composite structure also had a underlying influence in the friction behavior of nanoadditive.

SYNTHESIZING AND INVESTIGATING THE ELECTRICAL PROPERTIES OF CARBONIZED METAL–ORGANIC FRAMEWORKS

The iron-based metal–organic frame (Fe-MOF), VNU-20, and its carbonized analogues were synthesized. Subsequently, this material was investigated for electrical properties in comparison with the carbonized samples from other MOFs and ZIFs (such as ZIF-8, ZIF-67, MOF-199, MIL-53). The experiments showed the results with the reversible cyclic voltammetry (CV) curve characterized by the redox oxidation reactions of Fe(II)/Fe(III). Furthermore, the electrode composed of carbonized VNU-20 shows a comparable capacitance with that of carbonized ZIF-67, the highest capacitance material recorded up to date for the same class of materials. While further experiments need to be carried out for the optimization, initial analyzes show the promising result for further investigation and use of carbonized VNU-20 as the electrode material for electro-catalysis and the supercapacitor.

FRAME DESIGN OF INLINE SKATES MADE BY ADDITIVE TECHNOLOGY

The aim of the article was to investigate the possibility of topological optimization (TO) of the inline skate frame manufactured through the Powder Bed Fusion (PBF) method of AISi10Mg-0403, an Additive Manufacturing (AM) technique. The study's core objective was to leverage The Altair Inspire software to re-envision the initial CAD model, culminating in an organic and bionic frame design. Incorporating comprehensive load analysis, the research considered various load scenarios, including static mass, dynamic forces, and acceleration during cornering, to ascertain the frame's strength and stability. Topological optimization was excluded within a defined design space, preserving critical functional elements while enhancing performance. The first part of the article is devoted to defining the concepts and nature of AM metallic materials. The practical part follows, in which the design of the skate frame is specified with specific requirements and the procedure of individual steps needed to create its final CAD Model. The work concludes by describing the preparation of the designed optimized frame construction.

Covalent organic frame based high-performance nanocomposite for construction of ATP sensor

In this work, a novel covalent organic frame (TAPT-TFPB COF) with self-enhanced photoelectric activity was prepared for decorating on conductive single-walled carbon nanotubes (SWCNT) to synthetize a high-performance photoelectric nanocomposite (COF/SWCNT), in which the interfacial charge separation and photogenerated carrier migration rate was significantly improved to obtain desiring photoelectric conversion efficiency for generating an extremely high photocurrent. Accordingly, the synthetic COF/SWCNT was ingeniously applied in the fabrication of ultrasensitive photoelectrochemical (PEC) biosensor for realizing the trace ATP detection by integrating with an Exo III-assisted dual DNA recycling amplification strategy. The recycling amplification could efficiently convert trace target ATP into plentiful output DNA, which ingeniously triggered the hybridization chain reaction (HCR) to generate a long DNA strand with substantial quencher manganese porphyrin (MnPP) loading to depress the photocurrent of COF/SWCNT. The experimental data showed that proposed biosensor had a detection range from 10 fmol L−1 to 10 nmol L−1 with the detection limit as low as 2.75 fmol L−1 (S/N = 3). In addition, this proposed biosensor showed excellent analytical performance in terms of stability, specificity and reproducibility, providing a possibility to accomplish sensitive and accurate in vitro diagnosis.

Preparation of Zeolitic Imidazolate Framework and Carbon Nanofiber Composites for Nitrofurazone Detection

Metal–organic frame (MOF) materials may have the advantages of a regular pore structure, large porosity, and large specific surface area, which could provide better catalytic activity, but they have some disadvantages in electrocatalysis. In contrast, carbon nanofibers (CNFs) prepared by electrospinning methods have good conductivity and stability. Therefore, this research aimed to generate MOF/CNFs composite materials to improve the electrochemical properties of MOF materials and apply them to the field of electrochemical sensing. This experiment was based on the preparation of straight unidirectional CNFs by an electrospinning method at 2000 RPM. The original method of preparing zeolitic imidazolate frameworks (ZIF-8) was improved and ZIF-8 was uniformly dispersed on the surface of CNFs to form a ZIF-8/CNF composite with a fiber diameter of about 0.10 to 0.35 µm. The specific surface area of the CNFs was about 42.28 m2/g, while that of the ZIF-8/CNF composite was about 999.82 m2/g. The specific surface area of the ZIF-8/CNF composite was significantly larger than that of CNFs. The GCE/ZIF-8/CNF electrode had an excellent electrochemical reaction, with an oxidation peak at about 216 μA, which proved that the ZIF-8/CNF composite material would have good catalytic activity and excellent electrochemical properties for the detection of nitrofurazone compared to other modified electrodes.

Preparation of metal organic frame derived MgO-porous carbon composite and its high catalytic activity in ozonation with excellent stability

BackgroundOzone-based advanced oxidation technology has been extensively studied so far, but is hardly successfully used in treating actual wastewater. Preparation of a catalyst with high activity and stability, and insensitivity to quencher is still a big challenge in this field. MethodThe calcination of MOF-74 in inert gas resulted in a composite of the MgO-porous carbon, in which 2 nm MgO nanoparticles were uniformly distributed in porous carbon. Significant findingsThe specific surface area of MgO-PC composite (531.16 m²/g) was about 15 times that of MgO. The results of MgO-PC catalytic ozonation indicated it had not only high activity in ozonation of different organic but also excellent stability. The constant rate of p-CBA degradation in O3/MgO-PC only decreased from 11.63 × 10−2 min−1 to 9.36 × 10−2 min−1 after consecutive 15 cycles of the catalyst owing to the coating of porous carbon on nano particles of MgO. The most important thing is that O3/MgO-PC is a little insensitive to the free radical quenchers, which is an amazing result in progress of heterogeneous catalytic ozonation.

Synthesis of high-entropy oxides derived from metal–organic frameworks and their catalytic performance for total toluene oxidation

HEOs prepared from MOFs demonstrate excellent VOC removal performance.

Bimetallic nanoparticles preparation from metallic organic frameworks, characterization and its applications in reclamation of textile effluents

Abstract Herein bimetallic nanoparticles of Co–Mn were prepared using metal-organic framework (CoMn2 (C2O4)3·6H2O) as a starting material. Initially, the bimetallic organic frame work was prepared which was then subjected to pyrolysis to get the desired product. Techniques like scanning electron microscopy (SEM), Energy-Dispersive X-ray spectroscopy (EDX), X-ray Diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FTIR) were used to characterize the bimetallic nanoparticles. These analyses revealed that the Co–Mn nanoparticles consisted of finely distributed Mn and Co, along with O in the composites. XRD data confirmed the presence of nano-scale ranges and alloy formation between Co–Mn. The nanoparticles were employed as adsorbent for methyl violet adsorption, with optimized conditions found to be pH 9, temperature 333 K, adsorbents dosage of 0.01 g, and 30 min of contact time. The pseudo-second-order kinetic model best described the adsorption kinetics data whereas Langmuir isotherm exhibited the closest fit, with a maximum adsorption capacity of 625 mg/g at 333 K. Thermodynamic parameters indicated endothermic processes, with ΔH° = 15.155 kJ mol−1, and the process to be spontaneous with negative ΔG° values −0.303, −0.831, and −1.886 (kJ mol−1) at 293 K, 313 K, and 333 K, respectively. The ΔS° value of 52.76 J mol−1K−1 suggested increased disorder at the solid-solution interface during adsorption. The adsorbent could be effectively used in reclamation of dyes loaded water as alternative of activated carbon.

A swellable hydrogel microneedle based on cerium-metal organic frame composite nanozyme for detection of biomarkers

Skin interstitial fluid (ISF) has been an alternative source in the field of biomarkers analysis. This work developed swellable hydrogel microneedles (MNs) composed of polyvinyl alcohol and sodium alginate by chemical crosslinking (PVA/SA). Here, PVA/SA was firstly used to fabricate hydrogel MNs, achieving a swellable ratio of 150 % and a rapid extraction of 6.4 mg ISF in 15 min. To replace expensive and non-reusable test kits, hydrogel MNs based on composite nanozyme with high oxidase-like activity were successfully developed to recover and detect biomarkers. The nanozyme was composed of MnO2-modified mixed valence cerium-metal organic frame (MCM). MCM was characterized by multiple techniques to further confirm its composition and structure. MCM combined with the reduction reaction of glutathione (GSH) with oxidized substrate to achieve a colorimetric GSH detection, which had a detection limit (LOD, 0.36 μM) of GSH. The hydrogel MNs based on MCM (MCM-MNs) were firstly applied to the rapid detection of GSH in ISF. All in all, this method combines the advantages of nanozyme and hydrogel MNs to achieve a timely and minimally invasive analysis, which provides a new dimension for the in vivo detection of GSH by skin ISF and holds great implications in biomedical and bioanalysis fields.

Macromolecules cross linked-metal organic frame works based sensors for determination of memantine hydrochloride

Macromolecules cross linked-metal organic frame works based sensors for determination of memantine hydrochloride

Remediation of ibuprofen and naproxen in water by a green composite material of magnetic carbon nanotube–metal–organic framework

This work adopted a simple and green method for synthesizing a composite of magnetic carboxylic multi–walled carbon nanotube–metal–organic frame (MCNTs–UiO–66–NH2) at room temperature, which was applied to the remediation of ibuprofen (Ibu) and naproxen (Nap) in wastewater. The influencing factors of adsorption were investigated, including adsorbent dosage, pH value, coexisting ions, temperature, and contact time, etc. Various methods were employed for analyzing the structural features and surface characteristics exhibited by MCNTs–UiO–66–NH2. The values of max adsorption quantity about MCNTs–UiO–66–NH2 toward Ibu and Nap reached 143 mg·g–1 and 139 mg·g–1 at 313 K, respectively. The Langmuir model and Pseudo–second–order model can describe the adsorption process of Ibu and Nap. According to the values of the thermodynamic parameters, both adsorption processes were endothermic, spontaneous and could lead to an increase in entropy. In addition, the composite can be used to capture Ibu and Nap in the pH range of 1–10 and the salinity range of 0–0.2 mol·L–1 with an ideal regeneration performance taking 5 mmol·L–1 NaHCO3 as eluent. The mechanism of adsorption is including complexation, π–π conjugation, electrostatic action and H–bonding. These properties confirm MCNTs–UiO–66–NH2 as one potential adsorbent for remediation of Ibu and Nap in wastewater.

Characterization of an Iron-Copper Bimetallic Metal-Organic Framework for Adsorption of Methyl Orange in Aqueous Solution.

Iron-based organic frame material MIL-53 (Fe) was synthesized by the hydrothermal method with Cu2+ incorporated to obtain bimetallic composite MIL-53 (Fe, Cu). The structure and morphology of the material were characterized by SEM, XRD, BET, FTIR, XPS, and zeta potential. The adsorption performance of MIL-53 (Fe, Cu) on methyl orange was tested under a variety of conditions, including the effects of pH and material dosage, by the static adsorption test. The results show that under the condition of pH = 7, a temperature of 30°C, and an adsorbent dosage of 20 mg, the removal rate of MIL-53 (Fe, Cu) for methyl orange can reach more than 96% within 4 h, and the maximum adsorption capacity after fitting by the thermodynamic model can reach 294.43 mg/g, showing the excellent adsorption performance of MIL-53 (Fe, Cu) on methyl orange. In addition, by exploring the adsorption mechanism of MIL-53 (Fe, Cu) on methyl orange, it is found that the adsorption of MIL-53 (Fe, Cu) on methyl orange depends on chemical adsorption, as evidenced by combining Fe3+ and Cu2+ in the material with methyl orange molecules to form complexes to achieve adsorption. While the specific surface area of the material had no obvious effect on adsorption, the effects of pH, temperature, and concentration were explored. At a pH of 6.5, greater adsorption occurred at higher temperatures, as determined by thermodynamic model fitting, as well as with higher initial methyl orange molecule concentration.