ZIF-8 Nanoparticles Research Articles

A novel bis(β-Br-BODIPY) photosensitizer and its nanoscale delivery systems based on polymer micelles and zeolite-like MOFs

The design of biocompatible photosensitizers with an optimal combination of intense fluorescence and generation of singlet oxygen is a complex and urgent task. The article presents the results of synthesizing, analyzing the structure, and examining the chromophoric, fluorescent, and generation characteristics of new dimeric bis(β-Br-BODIPY) (1), as well as the features of its encapsulation in ZIF-8 zeolite framework and solubilization by Pluronic® F127 micelles. The photophysical characteristics of brominated dimer 1 were analyzed in comparison with non-halogenated dimers bis(β-H-BODIPY) (2), bis(β-CH3-BODIPY) (3), as well as dibromo-substituted mononuclear analogue β,β-dibromo-BODIPY (4). Dye 1 exhibits efficient fluorescence (from 53 to 72%) and 1O2 generation (from 19 to 42%) in solutions of nonpolar and weakly polar solvents. Dimerization leads to a high sensitivity of the fluorescence and generation characteristics of the halogenated dimer 1 to the solvent. The advantage of dimer 1 is a significantly lower tendency to aggregate compared to monomer 4. The conditions for the encapsulation of dye 1 in ZIF-8 nanoparticles and Pluronic® F127 micelles were determined and their structural and spectral characteristics were analyzed.

Preparation of ZIF-8 particles via solvent thermal synthesis and investigation of their photocatalytic hydrogen generation performance

In recent years, the preparation and application of ZIF-8 nanoparticles have garnered interest, yet systematic studies on the relationship between their size and photocatalytic hydrogen generation performance remain limited. Addressing this gap, the present study pioneers an in-depth exploration of the preparation of ZIF-8 nanoparticles, emphasizing their impact on photocatalytic hydrogen generation. A novel observation was made, where uniform ZIF-8 particles of approximately 1 micron were optimally synthesized at a molar ratio of zinc acetate to dimethylimidazole of 1:4. Interestingly, the study unveiled a unique trend of ZIF-8 particle size variation with changing reaction temperatures. Most notably, and for the first time, this research underscores the paramount role of particle size on ZIF-8’s hydrogen generation capability, connecting it intricately to the material’s pore characteristics. An unprecedented finding was the superior performance of the 500 nanometer-sized ZIF-8 in photocatalytic hydrogen generation, attributing its excellence to its pore size being finely attuned to the photocatalytic reaction requirements. Such groundbreaking insights not only deepen our comprehension of ZIF-8 materials but also hold transformative potential for the international engineering community, particularly in tailoring applications for enhanced photocatalytic hydrogen generation.

Metal Organic Framework-Incorporated Three-Dimensional (3D) Bio-Printable Hydrogels to Facilitate Bone Repair: Preparation and In Vitro Bioactivity Analysis.

Hydrogels are three-dimensional (3D) water-swellable polymeric matrices that are used extensively in tissue engineering and drug delivery. Hydrogels can be conformed into any desirable shape using 3D bio-printing, making them suitable for personalized treatment. Among the different 3D bio-printing techniques, digital light processing (DLP)-based printing offers the advantage of quickly fabricating high resolution structures, reducing the chances of cell damage during the printing process. Here, we have used DLP to 3D bio-print biocompatible gelatin methacrylate (GelMA) scaffolds intended for bone repair. GelMA is biocompatible, biodegradable, has integrin binding motifs that promote cell adhesion, and can be crosslinked easily to form hydrogels. However, GelMA on its own is incapable of promoting bone repair and must be supplemented with pharmaceutical molecules or growth factors, which can be toxic or expensive. To overcome this limitation, we introduced zinc-based metal-organic framework (MOF) nanoparticles into GelMA that can promote osteogenic differentiation, providing safer and more affordable alternatives to traditional methods. Incorporation of this nanoparticle into GelMA hydrogel has demonstrated significant improvement across multiple aspects, including bio-printability, and favorable mechanical properties (showing a significant increase in the compressive modulus from 52.14 ± 19.42 kPa to 128.13 ± 19.46 kPa with the addition of ZIF-8 nanoparticles). The designed nanocomposite hydrogels can also sustain drug (vancomycin) release (maximum 87.52 ± 1.6% cumulative amount) and exhibit a remarkable ability to differentiate human adipose-derived mesenchymal stem cells toward the osteogenic lineage. Furthermore, the formulated MOF-integrated nanocomposite hydrogel offers the unique capability to coat metallic implants intended for bone healing. Overall, the remarkable printability and coating ability displayed by the nanocomposite hydrogel presents itself as a promising candidate for drug delivery, cell delivery and bone tissue engineering applications.

The enhanced performance of Li-ion batteries based on Co-MOF/MXene composites

Electrospinning is carried out to fabricate Ti3C2Tx@Co nanocomposite films composed of 2D Ti3C2-encapsulated Co nanoparticles derived from Co-MOF precursors. The unique 1D nanochain structure inherits not only the high electrochemical activity, but also excellent electron and ionic conductivity. The Co nanoparticles with good conductivity and MXene with high electrochemical activity improve the electrochemical properties giving rise to high capacity and good cycling stability. The Ti3C2 flakes partially accommodate the volume changes during Li+ insertion/extraction and the electrospinning technique prevents self-aggregation of Ti3C2 flakes and aggregation of ZIF-67 nanoparticles, consequently producing a larger surface area and more active sites on the flexible anode. As a result, the MXene/Co composite has excellent properties such as a high reversible capacity of 422 mA h g−1 after 500 charging-discharging cycles at a current density of 1 A/g and retained capacity of 177 mA h g−1 at a rate of 5 A/g. The materials and strategy have large potential in commercial energy storage devices.

Degradation Kinetic Studies of BSA@ZIF-8 Nanoparticles with Various Zinc Precursors, Metal-to-Ligand Ratios, and pH Conditions.

Nanosized zeolitic imidazolate framework particles (ZIF-8 nanoparticles [NPs]) have strong potential as effective carriers for both in vivo and in vitro protein drug delivery. Synthesis of ZIF-8 and stability of protein encapsulation within ZIF-8 are affected by several factors, notably the metal ion source and molar ratio. To systematically investigate these factors, we investigated such effects using BSA as a model test protein to synthesize BSA@ZIF-8 NPs at various metal-to-ligand (M:L) ratios. SEM, FTIR, XRD, and DLS were applied to characterize the morphology and structure of BSA@ZIF-8 NPs and their effects on protein loading capacity. Degradation kinetics and protein release behavior of BSA@ZIF-8 NPs were evaluated at pH 5.0 (to simulate the tumor environment) and pH 7.4 (to mimic the blood environment). Our objective was to define optimal combinations of the high protein loading rate and rapid release under varying pH conditions, and we found that (i) the yield of BSA@ZIF-8 NPs decreased as the M:L ratio increased, but the protein content increased. This highlights the need to strike a balance between cost-effectiveness and practicality when selecting ZIF-8 NPs with different molar ratios for protein-based drug formulation. (ii) BSA@ZIF-8 NPs exhibited cruciate flower-like shapes when synthesized using Zn(NO3)2 as the zinc precursor at M:L ratios of 1:16 or 1:20. In all other cases, the NPs displayed a regular rhombic dodecahedral structure. Notably, the release behavior of the NPs did not differ significantly between these morphologies. (iii) When Zn(OAc)2 was used as the zinc precursor, the synthesized ZIF-8 NPs exhibited a smaller size compared to the Zn(NO3)2-derived ZIF-8 NPs. (iv) The release rate and amount of BSA protein were higher at pH 5.0 compared to pH 7.4. (v) Among the different formulations, BSA@ZIF-8 with an M:L ratio of 1:16 at pH 5.0 was observed to have a shorter time to reach a plateau (0.5 h) and higher protein release, making it suitable for locally rapid administration in a tumor environment. BSA@ZIF-8 prepared from Zn(OAc)2 at an M:L ratio of 1:140 showed the slower release of BSA protein over a 24-h period, indicating its suitability for sustained release delivery. In conclusion, our findings provide a useful basis for the practical application of ZIF-8 NPs in protein-based drug delivery systems.

Clever fusion of structure and function: A coupled sulfurization-driven OER performance study based on ZIF-67 nanoparticles and NiMoO4 nanorods

Hydrogen fuel cells (HFCs) and water electrolysis are emerging clean energy technologies that can alleviate the problems of environmental pollution and energy shortage. Oxygen Extraction Reaction (OER) is a slow four-electron transfer process with a high energy barrier, and often regarded as the bottleneck of a series of clean energy technologies. In this paper, NiMoO4 nanorods (denoted as NMO) were in situ grown on nickel foam substrate, and then ZIF-67 nanoparticles were assembled onto NiMoO4 nanorods (denoted as NMO@ZIF-67). Finally, the surface layers of NiMoO4 nanorods and ZIF-67 nanoparticles were vulcanized by hydrothermal treatment for 6 h to obtain the catalyst NiMoO4 @NiMoCo-S-6 (denoted as NMO@NMC-S-6). In 1 M KOH aqueous solution, NMO@NMC-S-6 exhibited excellent electrochemical performance, only 176 mV and 243 mV overpotentials were required at current densities of 10 and 100 mA cm-2, respectively, and Tafel slope of NMO@NMC-S-6 is 24.81 mV dec-1. In addition, benefitting from the combined structure of nanorods and nanoparticles effectively prevented nanoparticles aggregation and enhanced its own structure and transport channel stability, NMO@NMC-S-6 showed remarkable stability in 20 h electrochemical test. This work brings a reference orientation for constructing cost-efficient alkaline OER catalyst through structure combination strategy.

Facile in-situ growth of ZIF-67 nanoparticles and in-situ polymerization of polyacrylamide on chitosan aerogel spheres and their high-efficient adsorption of tetracycline

A compressible ZIF-67/polyacrylamide/chitosan composite aerogel (named as ZIF-67/PAM/CSA) is prepared by two-step method with in-situ polymerization and growth, which exhibits excellent compressible property and efficient adsorption performance of tetracycline. The loading capacity of ZIF-67 in ZIF-67/PAM/CSA can reach 42.7%, making the increased specific surface area up to 491.95 m2 g−1 for composite aerogel. For tetracycline adsorption, ZIF-67/PAM/CSA presents high capacity of 260.09 mg g−1 as well as stable enough recycling availability. The composite aerogel synthesized here with high specific surface area and compressibility, offers a promising method to branch out compressible adsorbents with benefits for the adsorption regeneration process in pollutant treatment applications.

ZIF-8 nanoparticles combined with fibroin protein co-modified TiO2 nanotube arrays to construct a drug sustained-release platform

Anodized titanium dioxide nanotubes (TNTs) on titanium surface provide a drug delivery platform for local drug therapy at the implantation site. Here, we used TNTs as the drug carrier and modified it with zeolite imidazolium salt skeleton-8 (ZIF-8) combined with silk fibroin (SF) to obtain a new drug loading platform to prolong the drug release time. The morphology, modification effect, drug release in vitro, cell biological activity and osteogenesis of the drug-loaded platform were evaluated. ZIF-8 nanoparticles are mesoporous and filled in nanotubes, and silk fibroin was covered on the surface of nanotubes in the form of thin films. In vitro drug release experiments showed that the silk fibroin membrane combined with biological crosslinking agent genipin (GNP) effectively blocked the diffusion of drugs and prolonged the drug release to 60 days. The study of cell proliferation and osteogenic differentiation showed that the drug-loaded platform was biocompatible and could promote ALP secretion. Therefore, the studies imply that the drug loading platform co-modified by TNTs-based ZIF-8 nanoparticles and silk fibroin can be used as a potential and ideal orthopedic implant.

Enhancing photocathodic protection with Bi quantum dots and ZIF-8 nanoparticle co-sensitized TiO2 nanotubes

Since hole trapping agents do not persist in the marine environment, it is more practical to test metal protection in 3.5 wt% NaCl solution so that the photocathodic protection (PCP) technique can be effectively applied in an actual marine environment. In this paper, Bi quantum dots (QDs) and ZIF-8 nanoparticles (NPs) were successfully deposited on TiO2 by hydrothermal and impregnation methods. The PCP performances of ZIF-8/Bi/TiO2 composites in the marine environment without hole trapping agents were evaluated, and compared with the performances of pure TiO2, Bi/TiO2 and ZIF-8/TiO2. The electrochemical impedance spectrum (EIS) fitting results demonstrate that the R ct value of the ZIF-8/Bi/TiO2 composite coupled with 316 stainless steel (SS) decreased from 7678 Ω cm2 to 519.3 Ω cm2 in 3.5 wt% NaCl solution, which is a decrease of about 14.8-fold compared with TiO2 under the same conditions. This indicates that the deposition of Bi QDs and ZIF-8 NPs on TiO2 nanotubes can improve the electron transport efficiency, which in turn slows down the rate of corrosion of 316 SS and significantly improves the PCP performance. This is not only attributable to the Schottky junction and heterojunction structures formed by Bi QDs and ZIF-8 NPs with TiO2, but also to the surface plasmon resonance effect of Bi QDs and the N–Ti–O bond structure formed between ZIF-8 and TiO2, leading to a lower electron–hole recombination efficiency and a higher electron transfer efficiency.

Large-scale preparation of UV photo-crosslinked composite membrane with high pervaporation desalination properties and excellent fouling resistance

In this study, we developed a high-performance composite membrane with rapid cross-linking and large-scale technology for PV desalination. Some strategies were adopted to achieve this purpose. First, photo cross-linking was used to shorten the cross-linking time of PVA within 60 s. Second, a PTFE microfiltration membrane was utilized as the substrate that mitigated the transport resistance of the supporting layer. Third, an large-scale spray-coating device was built-up which completed the amplification preparation of composite PV membrane. Finally, ZIF-8 nano-particle was introduced into the PVA layer that increased the free volume and amorphous region of PVA, enhancing the water flux of membrane. When desalted a 3.5 wt% NaCl solution at 80 °C, a water flux of 307.58 ± 15.09 kg/m2·h was achieved for the PVA/ZIF-8/PTFE composite membrane. To better reflect the membrane performance, the permeance of PVA/ZIF-8/PTFE membrane was also calculated, which was reached to 674.37 kg/m2 h bar, exceeding 18.4% than the highest reported property of PVA/PAN nanofiber membrane (569.55 kg/m2 h bar). In addition, the composite membrane showed stable water flux and salt rejection when treating highly concentrated brine solution containing organic pollutant. When desalinated a 10 wt% NaCl solution with 1 wt% HA at 80 °C, the PVA/ZIF-8/PTFE membrane produced water with low conductivity of 15.78 μs/cm and a high water flux of 129.95 kg/m2·h in a period of 180 min.

Adsorption of tetracycline from aqueous solution by ZIF-8: Isotherms, kinetics and thermodynamics

In this study, ZIF-8 nanoparticles were synthesized using a simple method at room temperature. The ZIF-8 nanoparticles were then characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), BET (Brunauer-Emmett-Teller) specific surface area, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA) and zeta potential. Subsequent batch adsorption experiments evaluated the adsorption performance of ZIF-8 on tetracycline, examining key pa-rameters like reaction time, pH, temperature, and adsorbent dosage. The results revealed a removal rate for TC of up to 90.59%. The adsorption data aligned with the Sips model, showcasing a maximum adsorption capacity of 359.61 mg/g at 303K. Further, the adsorption kinetics adhered to the pseudo-second-order kinetic model with an equilibrium adsorption capacity of 90 mg/g at 303K. The considerable specific surface area of ZIF-8, standing at 1674.169 m2/g, likely enhances the adsorption efficacy. Analysis using XRD and FTIR confirmed the adsorption of TC on the ma-terial's surface. Overall, the predominant driving forces behind the adsorption process were identified as electrostatic interactions and π-π stacking interactions.

A MOFs-Based mixed-matrix membrane with improved chemical stability and robust mechanical properties

Metal-organic frameworks (MOFs) based mixed-matrix membranes (MMMs) have exhibited unique superiority in various fields from gas separation to chemical sensing. However, their mechanical property and stability has not been fully explored yet, which was essential for further practical application. Herein, MOFs-based MMMs (ZIF-8@PU MMMs) with robust mechanical property and improved chemical stability were prepared through one-pot synthesis strategy by adding ZIF-8 nanoparticles with the monomers of polyurea (PU) during polymerization. Compared with intrinsic fragile and rigid characteristics of pure MOFs crystals films, these MMMs were flexible and free-standing. Importantly, the ZIF-8@PU MMMs exhibited improved mechanical properties compared with pure PU, and the chemical stability especially in acid environments was enhanced owing to the protection from the hydrophobic chain of polymers. This work demonstrated this one-pot strategy was feasible to fabricate homogeneous dispersed MOFs-based MMMs with improved mechanical property and chemical stability. This study was anticipated to accelerate the implementation of MOFs materials for industrialized applications.

A ZIF-8 modified aramid nanofiber separator against the shuttle effect for high performance lithium-sulfur batteries

Lithium-sulfur (Li-S) batteries are considered the most promising energy storage systems due to their high specific capacity and energy density. However, the practical application of lithium-sulfur batteries has been hampered by capacity loss due to the shuttle effect and serious safety issues due to the flammability and shrinkage of commercial diaphragms at high temperatures. Herein, we designed a separator by adding ZIF-8 nanoparticles to aramid nanofibers named ZIF-8/ANF. ANF has high flame retardant property and high mechanical strength to prevent separators failure at high temperature, preventing lithium dendrites from punctured separators and causing short circuit. ZIF-8 has the porous structure, while exposing abundant metal nodes acting as active sites, which can effectively adsorb polysulfides and inhibit the shuttle effect. As a result, the Li-S batteries with ZIF-8/ANF separators exhibit high specific discharge capacity and cycle performance. The Li-S batteries show a high initial specific capacity of 1178.3 mAh g−1 at 0.1 C and 525.9 mAh g−1 after 400 cycles. In addition, they also exhibit discharge capacity is 825.6 mAh g−1 at 0.2 C with the loading of 3.5 mg cm−2. This work offers a guidance for safe and high-performance Li-S batteries.

Stability of Filled PDMS Pervaporation Membranes in Bio-Ethanol Recovery from a Real Fermentation Broth.

Mixed matrix membranes (MMMs) have shown great potential in pervaporation (PV). As for many novel membrane materials however, lab-scale testing often involves synthetic feed solutions composed of mixed pure components, overlooking the possibly complex interactions and effects caused by the numerous other components in a real PV feed. This work studies the performance of MMMs with two different types of fillers, a core-shell material consisting of ZIF-8 coated on mesoporous silica and a hollow sphere of silicalite-1, in the PV of a real fermented wheat/hay straw hydrolysate broth for the production of bio-ethanol. All membranes, including a reference unfilled PDMS, show a declining permeability over time. Interestingly, the unfilled PDMS membrane maintains a stable separation factor, whereas the filled PDMS membranes rapidly lose selectivity to levels below that of the reference PDMS membrane. A membrane autopsy using XRD and SEM-EDX revealed an almost complete degradation of the crystalline ZIF-8 in the MMMs. Reference experiments with ZIF-8 nanoparticles in the fermentation broth demonstrated the influence of the broth on the ZIF-8 particles. However, the observed effects from the membrane autopsy could not exactly be replicated, likely due to distinct differences in conditions between the in-situ pervaporation process and the ex-situ reference experiments. These findings raise significant questions regarding the potential applicability of MOF-filled MMMs in real-feed pervaporation processes and, potentially, in harsh condition membrane separations in general. This study clearly confirms the importance of testing membranes in realistic conditions.

Spatiotemporal Controlled Formation of Synthetic Nanoreactors in Single Living Cells.

Cellular compartments provide confined environments for spatiotemporal control of biological processes and enzymatic reactions. To mimic such compartmentalization of eukaryotic cells, we report an efficient and general platform to precisely control the formation of artificial nanoreactors in single living cells. We introduce an electroosmotic controlled strategy for the synthesis of ZIF-8 at the nanoscale liquid-liquid interface around the tip of a nanopipet, whereby the formed ZIF-8 nanoparticles are driven into a single living cell by the electroosmotic flow. The porous ZIF-8 nanoparticles, as synthetic nanoreactors, are not only able to harvest fluorescent molecules from peripheral cytoplasm but also perform the subsequent photocatalytic degradation, mimicking compartmentalized chemical reactions in eukaryotic cells. Our strategy provides a useful tool for spatiotemporal controlled synthesis of artificial nanoreactors with on-demand functions in single living cells with versatile applications in chemical biology.

Hydrophilic-hydrophobic bilayer interlayer for high performance thin-film composite reverse osmosis membranes

The strategy of modifying substrates with hydrophilic interlayers has been widely used to improve the performance of thin-film composite (TFC) nanofiltration (NF) membranes. However, the preparation of TFC reverse osmosis (RO) membranes with excellent performance on hydrophilic substrates through conventional interfacial polymerization (IP) method has proven to be very challenging. In this work, a hydrophilic polycarboxylic acid – hydrophobic ZIF-8 nanoparticles bilayer interlayer was developed to enhance the performance of TFC RO membranes. Based on this, the interlayer was designed to improve the performance of TFC RO membranes by creating a synergistic effect between the hydrophilic polycarboxylic acid and the hydrophobic ZIF-8 nanoparticles. The hydrophilic polycarboxylic acid interlayer was used to heal defects in the PSF substrate and provide growth sites for the in-situ growth of ZIF-8 nanoparticles. Hydrophobic ZIF-8 nanoparticles weakened the inhibition of the hydrophilic polycarboxylic acid interlayer on the diffusion of MPD, thus promoting the IP reaction and forming a dense PA separation layer (NaCl rejection 98.8%). The modulation of MPD erupted from the pores of the modified substrate by the bilayer interlayer results in the formation of an asymmetric PA layer, which has a dense PA in the upper region and loose PA encapsulating ZIF-8 nanoparticles in the lower region. ZIF-8 nanoparticles encapsulated by PA not only provided a low-resistance channel for water to pass through the separation layer but also enhanced the compaction resistance of the RO membrane, thus improving the permeance of the TFC RO membrane (4.2 L m−2 h−1·bar−1). In addition, thanks to the good compatibility between ZIF-8 nanoparticles and the PA matrix, as well as the smoother PA layer, TFC RO membranes with the bilayer interlayer presented excellent long-term stability and antifouling ability. This work presents a new idea to improve the performance of TFC RO membranes using interlayer strategies.

Single-Cell Diagnosis of Cancer Drug Resistance through the Differential Endocytosis of Nanoparticles between Drug-Resistant and Drug-Sensitive Cancer Cells.

Single-cell diagnosis of cancer drug resistance is highly relevant for cancer treatment, as it can be used to identify the subpopulations of drug-resistant cancer cells, reveal the sensitivity of cancer cells to treatment, and monitor the progress of cancer drug resistance. However, simple and effective methods for cancer drug resistance detection at the single-cell level are still lacking in laboratory and clinical studies. Inspired by the fact that nanoparticles with diverse physicochemical properties would generate distinct and specific interactions with drug-resistant and drug-sensitive cancer cells, which have distinctive molecular signatures, here, we have synthesized a library of fluorescent nanoparticles with various sizes, surface charges, and compositions (SiO2 nanoparticles (SNPs), organic PS-co-PAA nanoparticles (ONPs), and ZIF-8 nanoparticles (ZNPs)), thus demonstrating that the composition has a critical influence on the interaction of nanoparticles with drug-resistant cancer cells. Furthermore, the clathrin/caveolae-independent endocytosis of ZNPs together with the P-glycoprotein-related decreased cell membrane fluidity resulted in a lower cellular accumulation of ZNPs in drug-resistant cancer cells, consequently causing the distinct cellular accumulation of ZNPs between the drug-resistant and drug-sensitive cancer cells. This difference was further quantified by detecting the fluorescence signals generated by the accumulation of nanoparticles at the single-cell level via flow cytometry. Our findings provide another insight into the nanoparticle-cell interactions and offer a promising platform for the diagnosis of cancer drug resistance of various cancer cells and clinical cancer samples at the single-cell level.

The Importance of Dean Flow in Microfluidic Nanoparticle Synthesis: A ZIF-8 Case Study.

The Dean Flow, a physics phenomenon that accounts for the impact of channel curvature on fluid dynamics, has great potential to be used in microfluidic synthesis of nanoparticles. This study explores the impact of the Dean Flow on the synthesis of ZIF-8 particles. Several variables that influence the Dean Equation (the mathematical expression of Dean Flow) are tested to validate the applicability of this expression in microfluidic synthesis, including the flow rate, radius of curvature, channel cross sectional area, and reagent concentration. It is demonstrated that the current standard of reporting, providing only the flow rate and crucially not the radius of curvature, is an incomplete description that will invariably lead to irreproducible syntheses across different laboratories. An alternative standard of reporting is presented and it is demonstrated how the sleek and simple math of the Dean Equation can be used to precisely tune the final dimensions of high quality, monodisperse ZIF-8 nanoparticles between 40 and 700nm.

Heteroepitaxial growth of ZIF-67 nanoparticles on the ZIF-L(Zn) nanosheets for fabrication of Pebax mixed matrix membranes with highly efficient CO2 separation

ZIF-67 nanoparticles were grown on ZIF-L(Zn) nanosheets by in-situ heteroepitaxial method, resulting in ZIF-67@ZIF-L(Zn) as a charming two-dimensional (2D) nanocomposite for incorporation into the Pebax-1657 and improving its CO2/N2 separation performance. The fabricated nanofillers and membranes were analyzed by characterization tests (FTIR, XRD, FESEM, and EDAX-mapping) and gas separation experiments (effect of filler loading, filler type, feed pressure, and long-term stability). It was observed that the nanosheets were well dispersed in the matrix, and they had formed a proper interaction by creating hydrogen bonds at the interface; in addition, due to their crystalline nature, they increased the crystallinity of the MMMs. The results of the gas permeability test showed that these nanofillers, with their composite structure, had a synergistic effect on the gas solubility and screening and caused a significant improvement in the separation performance of MMMs. So that the best performance achieved with a CO2 permeability of 72.9 Barrer and a CO2/N2 selectivity of 102.9 at 10 bar for the MMM containing 2 wt% of ZIF-L(Zn)@ZIF-67, also exceeding Robeson's upper bound. Moreover, Mindex as a criterion for evaluation of the gas separation performance of MMMs in simultaneous improvement of the permeability and selectivity was proposed in this work. The Mindex values in the range of 0.5–1.5 were calculated for the MMM containing 2 wt% of ZIF-L(Zn)@ZIF-67 nanosheet which indicating a good quality for the gas separation performance. Furthermore, at equal filler loading (2 wt%), this membrane outperformed all MMMs containing other nanofillers (ZIF-67, ZIF-8, ZIF-L(Co), or ZIF-L(Zn)).

Effective removal of arsenite from water using polylactic acid ZIF-8 biocomposite nanofiber

Water purification from As(III)-contaminated groundwater is difficult but highly needed. Herein, a new polylactic acid ZIF-8 biocomposite nanofiber mat (ZIF-8@PLA/NFM) was fabricated using an electrospinning technique for As(III) decontamination. The active component, ZIF-8 nanoparticles, are uniformly embedded in sustainable PLA fibers and can be rapidly contacted by As(III), achieving fast kinetics and high utilization of nanoparticles. The removal experiments show that the ZIF-8@PLA/NFM can effectively remove As(III), especially in combination with H2O2. The 50%-ZIF-8@PLA/NFM with 1 mM H2O2 reduced 1000 μg/L As(III) to less than 10 μg/L in just 5 min through the synergy of oxidation and adsorption. The maximum sorption capacity for As(III) on 50-ZIF-8@PLA/NFM was 11.61 ± 0.99 mg/g, which increased to 39.25 ± 3.84 mg/g with the addition of H2O2. It performed well in the pH range of 4–9. The combination of H2O2 broadened its effective pH operating range (3–10) as well as enhanced interference resistance, enabling deep removal of As(III) across a wide range of water environments. The As(III)-spiked natural water (100 μg/L) could be purified to drinking standard level by ZIF-8@PLA/NFM within 60 min. In combination with H2O2, the removal efficiency was reduced by only 1.5% at the fifth reuse. Macroscopic experiments and microscopic characterization suggest that the adsorption follows the inner-sphere complexes mechanism. The study provides a novel approach for the fabrication of efficient, easy-to-use, and sustainable MOFs-based biocomposite for As(III) decontamination.