Magnetic Hollow Fibers of Covalent Organic Frameworks (COF) for Pollutant Degradation and Adsorptive Removal.

The shaping of covalent organic frameworks (COFs), requiring the conversion of non-processible COF powders into applicable architectures with additional functionality, remains a challenge. Using pre-electrospun polymer fibers as a sacrificial template, herein, we report a green synthesis of an architecture in the form of COF hollow fibers with an inner layer of peroxidase-like iron oxide nanoparticles as a catalytic material. When compared to peroxidase-like pristine iron oxide nanoparticles, these COF hollow fibers demonstrate higher catalytic breakdown of crystal violet due to their peroxidase-like activity via advanced oxidation process. Furthermore, as a potential adsorbent, hollow COF fibers exhibit significantly effective adsorption capacity and removal efficiency of organic solvent and oil from water. Because of their magnetic nature, COF hollow fibers can be easily recovered and have exhibited high recycling stability for both catalytic dye degradation and organic solvent removal from water.

A Hydrophilic Metal Azolate Coordination Polymer for In Situ Encapsulation of Haloalkane Dehalogenase with Enhanced Enzymatic Performance.

Encapsulating enzymes within metal-organic frameworks such as zeolitic imidazolate framework-8 (ZIF-8) has been demonstrated to enhance enzymatic performance under harsh conditions. However, by computer-aided analysis, we revealed that highly hydrophobic organic ligands and unfavorable metal ions could greatly impair the activity of haloalkane dehalogenase DhaA by directly interacting with the catalytic sites, causing an extremely low activity of DhaA after encapsulating within ZIF-8. We also found that the presence of a protecting polymer could protect DhaA from the damage of organic ligands and metal ions and that a positively charged amino acid could increase the DhaA activity. Based on the simulations and experimental observations, we have designed to coencapsulate DhaA with poly(vinylpyrrolidone) (PVP) and lysine (Lys) within the amorphous Co-based metal azolate coordination polymer (CoCP). The as-prepared immobilized enzyme (DhaA/PVP/Lys@CoCP) exhibited significantly increased activity (91.5 times higher than that of DhaA@ZIF-8), dramatically enhanced thermostability at 50-70 °C, greatly improved catalytic performance in several organic solvent solutions, and good recyclability (over 75% of the initial activity after 10 cycles). The superiority of the immobilized enzyme was also demonstrated with a substrate frequently detected in the real world. In addition to the protective effect of PVP and positive effect of Lys, experimental and computational investigations unveiled other two favorable aspects that contributed to the enhanced enzymatic performance: (1) high hydrophilicity of the immobilization material and (2) the use of Co2+ with a minimal negative effect on DhaA. The research has thus provided a promising immobilized DhaA with favorable catalytic performance and great potential in industrial applications.

Elucidation of the effects of 2,5-hexandione as a metabolite of n-hexane on cognitive impairment in leptin-knockout mice (C57BL/6-Lepem1Shwl/Korl).

Exposure to n-hexane and its metabolite 2,5-hexandione (HD) is a well-known cause of neurotoxicity, particularly in the peripheral nervous system. To date, few studies have focused on the neurotoxic effects of HD on cognitive impairment. Exposure to HD and diabetes mellitus can exacerbate neurotoxicity. There are links among HD, diabetes mellitus, and cognitive impairment; however, the specific mechanisms underlying them remain unclear. Therefore, we aimed to elucidate the neurotoxic effects of HD on cognitive impairment in ob/ob (C57BL/6-Lepem1Shwl/Korl) mice. We found that HD induced cognitive impairment by altering the expression of genes (FN1, AGT, ACTA2, MYH11, MKI67, MET, CTGF, and CD44), miRNAs (mmu-miR15a-5p, mmu-miR-17-5p, and mmu-miR-29a-3p), transcription factors (transcription factor AP-2 alpha [TFAP2A], serum response factor [Srf], and paired box gene 4 [PAX4]), and signaling pathways (ERK/CERB, PI3K/AKT, GSK-3ß/p-tau/amyloid-ß), as well as by causing neuroinflammation (TREM1/DAP12/NF-κB), oxidative stress, and apoptosis. The prevalent use of n-hexane in various industrial applications (for instance, shoe manufacturing, printing inks, paints, and varnishes) suggests that individuals with elevated body weight and glucose levels and those employed in high-risk workplaces have greater probability of cognitive impairment. Therefore, implementing screening strategies for HD-induced cognitive dysfunction is crucial. Supplementary Information: The online version contains supplementary material available at 10.1007/s43188-024-00228-1.

Vapor/Vapor-Solid Interfacial Growth of Covalent Organic Framework Membranes on Alumina Hollow Fiber for Advanced Molecular Separation.

Covalent organic frameworks (COFs), known for their chemical stability and porous crystalline structure, hold promises as advanced separation membranes. However, fabricating high-quality COF membranes, particularly on industrial-preferred hollow fiber substrates, remains challenging. This study introduces a novel vapor/vapor-solid (V/V-S) method for growing ultrathin crystalline TpPa-1 COF membranes on the inner lumen surface of alumina hollow fibers (TpPa-1/Alumina). Through vapor-phase monomer introduction onto polydopamine-modified alumina at 170 °C and 1 atm, efficient polymerization and crystallization occur at the confined V-S interface. This enables one-step growth within 8 h, producing 100 nm thick COF membranes with strong substrate adhesion. TpPa-1/Alumina exhibits exceptional stability and performance over 80 h in continuous cross-flow organic solvent nanofiltration (OSN), with methanol permeance of about 200 L m-2 h-1 bar-1 and dye rejection with molecular weight cutoff (MWCO) of approximately 700 Da. Moreover, the versatile V/V-S method synthesizes two additional COF membranes (TpPa2Cl/Alumina and TpHz/Alumina) with different pore sizes and chemical environments. Adjusting the COF membrane thickness between 100-500 nm is achievable easily by varying the growth cycle numbers. Notably, TpPa2Cl/Alumina demonstrates excellent OSN performance in separating the model active pharmaceutical ingredient glycyrrhizic acid (GA) from dimethyl sulfoxide (DMSO), highlighting the method's potential for large-scale industrial applications.

Fabrication of Coffee-Ring Nanostructured Membranes for Organic Solvent Nanofiltration.

Organic solvent nanofiltration (OSN) plays important roles in pharmaceutical ingredients purification and solvent recovery. However, the low organic solvent permeance under cross-flow operation of OSN membrane hampers their industrial applications. Herein, we report the construction of coffee-ring structured membrane featuring high OSN permeance. A water-insoluble crystal monomer that dissolved in EtOH/H2O mixed solvent was designed to react with trimesoyl chloride via interfacial polymerization. Owing to the diffusion of EtOH to n-hexane, coffee-ring nanostructure on the support membrane appeared, which served as the template for construction of coffee-ring structured membrane. The optimal nanostructured membrane demonstrated 2.6-fold enhancement in the effective surface area with reduced membrane thickness. Resultantly, the membrane afforded a 2.7-fold enhancement in organic solvent permeance, e.g., ~13 LMH/bar for MeOH, without sacrificing the rejection ability. Moreover, due to the rigid monomer structure, the fabricated membrane shows distinctive running stability in active pharmaceutical ingredients purification and the ability for concentration of medicines.

Organic-solvent ditch overlap in reversed-phase liquid chromatography: A molecular dynamics simulation study in cylindrical 6-12 nm-diameter pores.

Mass transport through the mesopore space of a reversed-phase liquid chromatography (RPLC) column depends on the properties of the chromatographic interface, particularly on the extent of the organic-solvent ditch that favors the analyte surface diffusivity. Through molecular dynamics simulations in cylindrical RPLC mesopore models with pore diameters between 6 and 12 nm we systematically trace the evolution of organic-solvent ditch overlap due to spatial confinement in the mesopore space of RPLC columns for small-molecule separations. Each pore model of a silica-based, endcapped, C18-stationary phase is equilibrated with two mobile phases of comparable elution strength, namely 70/30 (v/v) water/acetonitrile and 60/40 (v/v) water/methanol, to consider the influence of the mobile-phase composition on the onset of organic-solvent ditch overlap. The simulations show that, as the pore diameter decreases from 9 to 6 nm, the bonded-phase density extends and compacts towards the pore center, which leads to increased accumulation of organic-solvent excess and thus enhanced organic-solvent diffusivity in the ditch. Because the acetonitrile ditch is more pronounced than the methanol ditch, acetonitrile ditch overlap sets in at less severe spatial confinement than methanol ditch overlap. The pore-averaged methanol and acetonitrile diffusivities are considerably raised by ditch overlap in the 6 nm-diameter pore, but also benefit from the ditch (without overlap) in the 7 to 12 nm-diameter pores, whereby local and pore-averaged effects are generally larger for acetonitrile than methanol.

Organic Solvent Boosts Charge Storage and Charging Dynamics of Conductive MOF Supercapacitors.

Conductive metal-organic frameworks (c-MOFs) and ionic liquids (ILs) have emerged as auspicious combinations for high-performance supercapacitors. However, the nanoconfinement from c-MOFs and high viscosity of ILs slow down the charging process. This hindrance can, however, be resolved by adding solvent. Here, constant-potential molecular simulations are performed to scrutinize the solvent impact on charge storage and charging dynamics of MOF-IL-based supercapacitors. Conditions for >100% enhancement in capacity and ≈6 times increase in charging speed are found. These improvements are confirmed by synthesizing near-ideal c-MOFs and developing multiscale models linking molecular simulations to electrochemical measurements. Fundamentally, the findings elucidate that the solvent acts as an "ionophobic agent" to induce a substantial enhancement in charge storage, and as an "ion traffic police" to eliminate convoluted counterion and co-ion motion paths and create two distinct ion transport highways to accelerate charging dynamics. This work paves the way for the optimal design of MOF supercapacitors.

Alkane-Translocated Cells of Rhodococcus Strains Utilize Dissolved Oxygen in the Alkane Phase of an Aqueous-Alkane Two-phase Culture.

To clarify the growth mechanisms of Rhodococcus in the alkane phase, we measured oxygen utilization in the alkane phase. The results showed that dissolved oxygen decreased significantly when viable cells were present in the alkane phase. The findings suggested that Rhodococcus strains can grow in alkanes and utilize the resident dissolved oxygen.

Adhesive Zwitterionic Poly(ionic liquid) with Unprecedented Organic Solvent Resistance.

The resistance of adhesives to organic solvents is of paramount importance in diverse industries. Unfortunately, many currently available adhesives exhibit either weak intermolecular chain interactions, resulting in insufficient resistance to organic solvents, or possess a permanent covalent crosslinked network, impeding recyclability. This study introduces an innovative approach to address this challenge by formulating zwitterionic poly(ionic liquid) (ZPIL) derivatives with robust dipole-dipole interactions, incorporating sulfonic anions and imidazolium cations. Due to its unique dynamic and electrostatic self-crosslinking structure, the ZPIL exhibits significant adhesion to various substrates and demonstrates excellent recyclability even after multiple adhesion tests. Significantly, ZPIL exhibits exceptional adhesion stability across diverse nonpolar and polar organic solvents, including ionic liquids, distinguishing itself from nonionic polymers and conventional poly(ionic liquid)s. Its adhesive performance remains minimally affected even after prolonged exposure to soaking conditions. The study presents a promising solution for the design of highly organic solvent-resistant materials for plastics, coatings, and adhesives.

Integrated Membrane Process in Organic Media: Combining Organic Solvent Ultrafiltration, Nanofiltration, and Reverse Osmosis to Purify and Concentrate the Phenolic Compounds from Wet Olive Pomace.

Phenolic compounds from a hydroalcoholic extract of wet olive pomace were purified and concentrated by an integrated membrane process in organic media. First, UF010104 (Solsep BV) and UP005 (Microdyn Nadir) membranes were tested to be implemented in the ultrafiltration stage, with the aim of purifying the extract and obtaining a permeate enriched in phenolic compounds. Despite the high flux observed with the UF010104 membrane (20.4 ± 0.7 L·h-1·m-2, at 2 bar), the UP005 membrane was selected because of a more suitable selectivity. Even though some secoiridoids were rejected, the permeate stream obtained with this membrane contained high concentrations of valuable simple phenols and phenolic acids, whereas sugars and macromolecules were retained. Then, the ultrafiltration permeate was subjected to a nanofiltration step employing an NF270 membrane (DuPont) for a further purification and fractionation of the phenolic compounds. The permeate flux was 50.2 ± 0.2 L·h-1·m-2, working at 15 bar. Hydroxytyrosol and some phenolic acids (such as vanillic acid, caffeic acid, and ferulic acid) were recovered in the permeate, which was later concentrated by reverse osmosis employing an NF90 membrane. The permeate flux obtained with this membrane was 15.3 ± 0.3 L·h-1·m-2. The concentrated phenolic mixture that was obtained may have important applications as a powerful antioxidant and for the prevention of diabetes and neurodegenerative diseases.

Scalable, Interfacially Synthesized, Covalent-Organic Framework (COF)-Based Thin-Film Composite (TFC) Hollow Fiber Membranes for Organic Solvent Nanofiltration (OSN).

Covalent organic frameworks have great potential for energy-efficient molecular sieving-based separation. However, it remains challenging to implement COFs as an alternative membrane material due to the lack of a scalable and cost-effective fabrication mechanism. This work depicts a new method for fabricating a scalable in situ COF hollow fiber (HF) membrane by an interfacial polymerization (IP) approach at room temperature. The 2D COF film was constructed on a polyacrylonitrile HF substrate using aldehyde (1,3,5-trimethylphloroglucinol, Tp) and amine (4,4'-azodianiline (Azo) and 4,4',4″-(1,3,5-triazine- 2,4,6-triyl) trianiline (Tta)) as precursors. The COF membrane on the PAN substrate showed 99% rejection of Direct red-80 with remarkable solvent permeance. The rejection analysis revealed that the structural aspects of the solute molecule play a major role in rejection rather than the molecular weight. We further optimized the precursor concentrations to improve the permeation performance of the resulting membrane. The durability study reveals excellent stability of the membrane toward organic solvents. This study also demonstrated the easy scalability of the membrane fabrication approach. The approach was further extrapolated to fabricate a cation-based COF membrane. These charged membranes exhibited an enhanced rejection performance. Finally, this approach can facilitate industrially challenging molecular sieving applications using COF-based membranes.

Tunable 2D Conjugated Porous Organic Polymer Films for Precise Molecular Nanofiltration and Optoelectronics.

Structural design of 2D conjugated porous organic polymer films (2D CPOPs), by tuning linkage chemistries and pore sizes, provides great adaptability for various applications, including membrane separation. Here, four free-standing 2D CPOP films of imine- or hydrazone-linked polymers (ILP/HLP) in combination with benzene (B-ILP/HLP) and triphenylbenzene (TPB-ILP/HLP) aromatic cores are synthesized. The anisotropic disordered films, composed of polymeric layered structures, can be exfoliated into ultrathin 2D-nanosheets with layer-dependent electrical properties. The bulk CPOP films exhibit structure-dependent optical properties, triboelectric nanogenerator output, and robust mechanical properties, rivaling previously reported 2D polymers and porous materials. The exfoliation energies of the 2D CPOPs and their mechanical behavior at the molecular level are investigated using density function theory (DFT) and molecular dynamics (MD) simulations, respectively. Exploiting the structural tunability, the comparative organic solvent nanofiltration (OSN) performance of six membranes having different pore sizes and linkages to yield valuable trends in molecular weight selectivity is investigated. Interestingly, the OSN performances follow the predicted transport modeling values based on theoretical pore size calculations, signifying the existence of permanent porosity in these materials. The membranes exhibit excellent stability in organic solvents at high pressures devoid of any structural deformations, revealing their potential in practical OSN applications.

Synthesis optimization and separation mechanism of ZSM-5 zeolite membranes for pervaporation dehydration of organic solvents.

Pervaporation (PV), as an energy-efficient mixture separation technology, plays an important role in the chemical industry. In this work, no organic templates were needed to produce high-performance ZSM-5 membranes with an extremely low Si/Al ratio of 3.3 on α-Al2O3 tubular supports using 100 nm nanoseeds. The effects of preparation parameters on the crystalline phase structures, micromorphologies, and PV separation performance of ZSM-5 membranes were comprehensively investigated. The results revealed that the Si/Al ratio of gels significantly affected both the Si/Al ratio and the crystal orientation of the final ZSM-5 membrane. The optimized ZSM-5 membrane with a thickness of 1.8 µm was utilized to dehydrate various organic solvents via PV, and the influence of the operating parameters on PV dehydration performance was evaluated and is described herein. Furthermore, the permeation behaviors of single gases and PV were examined using permeate molecules within a similar size range to reveal the PV mechanism of the ZSM-5 membrane. The results demonstrated that gas permeation followed Knudsen diffusion, while PV permeation was decreased with decreases in the affinity of molecules, revealing an adsorption-diffusion mechanism that dominated PV dehydration through the ZSM-5 membrane. Moreover, the as-synthesized ZSM-5 membrane had good water permselectivity for water/acetone (e.g., total flux = 1.03 kg/(m2 h), α = 307) and for water/isopropanol (e.g., total flux = 1.49 kg/(m2 h), α = 1070) mixtures compared with other membranes reviewed in the literature. The synthesized ZSM-5 membrane also exhibited excellent reproducibility, high stability, and attractive PV separation performance, demonstrating its significant potential application in the PV dehydration of organic solvents.

Computer-aided design to enhance the stability of aldo-keto reductase KdAKR.

The aldo-keto reductase (AKR) KdAKR from Kluyvermyces dobzhanskii can reduce t-butyl 6-chloro-(5S)-hydroxy-3-oxohexanoate ((5S)-CHOH) to t-butyl 6-chloro-(3R,5S)-dihydroxyhexanoate ((3R,5S)-CDHH), which is the key chiral intermediate of rosuvastatin. Herein, a computer-aided design that combined the use of PROSS platform and consensus design was employed to improve the stability of a previously constructed mutant KdAKRM6 . Experimental verification revealed that S196C, T232A, V264I and V45L produced improved thermostability and activity. The "best" mutant KdAKRM10 (KdAKRM6 -S196C/T232A/V264I/V45L) was constructed by combining the four beneficial mutations, which displayed enhanced thermostability. Its T50 15 and Tm values were increased by 10.2 and 10.0°C, respectively, and half-life (t1/2 ) at 40°C was increased by 17.6 h. Additionally, KdAKRM10 demonstrated improved resistance to organic solvents compared to that of KdAKRM6 . Structural analysis revealed that the increased number of hydrogen bonds and stabilized hydrophobic core contributed to the rigidity of KdAKRM10 , thus improving its stability. The results validated the feasibility of the computer-aided design strategy in improving the stability of AKRs.

Managing PFAS exhausted Ion-exchange resins through effective regeneration/electrochemical process.

This study proposes an integrated approach that combines ion-exchange (IX) and electrochemical technologies to tackle problems associated with PFAS contamination. Our investigation centers on evaluating the recovery and efficiency of IX/electrochemical systems in the presence of five different salts, spanning dosages from 0.1 % to 8 %. The outcomes reveal a slight superiority for NaCl within the regeneration system, with sulfate and bicarbonate also showing comparable efficacy. Notably, the introduction of chloride ion (Cl-) into the electrochemical system results in substantial generation of undesirable chlorate (ClO3-) and perchlorate (ClO4-) by-products, accounting for ∼18 % and ∼81 % of the consumed Cl-, respectively. Several agents, including H2O2, KI, and Na2S2O3, exhibited effective mitigation of ClO3- and ClO4- formation. However, only H2O2 demonstrated a favorable influence on the degradation and defluorination of PFOA. The addition of 0.8 M H2O2 resulted in the near-complete removal of ClO3- and ClO4-, accompanied by 1.3 and 2.2-fold enhancements in the degradation and defluorination of PFOA, respectively. Furthermore, a comparative analysis of different salts in the electrochemical system reveals that Cl- and OH- ions exhibit slower performance, possibly due to competitive interactions with PFOA on the anode's reactive sites. In contrast, sulfate and bicarbonate salts consistently demonstrate robust decomposition efficiencies. Despite the notable enhancement in IX regeneration efficacy facilitated by the presence of methanol, particularly for PFAS-specific resins, this enhancement comes at the cost of reduced electrochemical decomposition of all PFAS. The average decay rate ratio of all PFAS in the presence of 50 % methanol, compared to its absence, falls within the range of 0.11-0.39. In conclusion, the use of 1 % Na2SO4 salt stands out as a favorable option for the integrated IX/electrochemical process. This choice not only eliminates the need to introduce an additional chemical (e.g., H2O2) into the wastewater stream, but also ensures both satisfactory regeneration recovery and efficiency in the decomposition process through electrochemical treatment.

On-Demand Crack Formation on DNA Film via Organic Solvent-Induced Dehydration.

Crack is found on the soil when severe drought comes, which inspires the idea to rationalize patterning applications using dried deoxyribonucleic acid (DNA) film. DNA is one of the massively produced biomaterials in nature, showing the lyotropic liquid crystal (LC) phase in highly concentrated conditions. DNA nanostructures in the hydrated condition can be orientation controlled, which can be extended to make dryinginduced cracks. The controlled crack generation in oriented DNA films by inducing mechanical fracture through organic solvent-induced dehydration (OSID) using tetrahydrofuran (THF) is explored. The corresponding simulations show a strong correlation between the long axis of DNA due to the shrinkage during the dehydration and in the direction of crack propagation. The cracks are controlled by simple brushing and a 3D printing method. This facile way of aligning cracks will be used in potential patterning applications.

Engineering diaryl alcohol dehydrogenase KpADH reveals importance of retaining hydration shell in organic solvent tolerance.

Alcohol dehydrogenases (ADHs) are synthetically important biocatalysts for the asymmetric synthesis of chiral alcohols. The catalytic performance of ADHs in the presence of organic solvents is often important since most prochiral ketones are highly hydrophobic. Here, the organic solvent tolerance of KpADH from Kluyveromyces polyspora was semi-rationally evolved. Using tolerant variants obtained, meticulous experiments and computational studies were conducted to explore properties including stability, activity and kinetics in the presence of various organic solvents. Compared with WT, variant V231D exhibited 1.9-fold improvement in ethanol tolerance, while S237G showed a 6-fold increase in catalytic efficiency, a higher T 50 15 $$ {\mathrm{T}}_{50}^{15} $$ , as well as 15% higher tolerance in 7.5% (v/v) ethanol. Based on 3 × 100 ns MD simulations, the increased tolerance of V231D and S237G against ethanol may be ascribed to their enhanced ability in retaining water molecules and repelling ethanol molecules. Moreover, 6.3-fold decreased KM value of V231D toward hydrophilic ketone substrate confirmed its capability of retaining hydration shell. Our results suggest that retaining hydration shell surrounding KpADH is critical for its tolerance to organic solvents, as well as catalytic performance. This study provides useful guidance for engineering organic solvent tolerance of KpADH and other ADHs.

Examination of Permeation Resistance of Chemical Protective Gloves Made of Laminate-Film Materials Against Chemical Substances.

This study investigated the permeation resistance of chemical protective gloves made of laminate film comprising nylon, ethylene-vinyl alcohol copolymer (EVOH), and other materials against different chemical substances to examine their usability in different work processes. The permeation resistance of the chemical protective glove was tested using the Japanese Industrial Standards (JIS) test method against twelve substances: acetone, acetonitrile, dichloromethane, ethyl acetate, n-hexane, methanol, tetrahydrofuran, toluene, 2-propanol, 1-butanol, 1,4-diethylene dioxide, and ethanol. After 480 min, no substance, except for methanol and ethanol, permeated at a standard permeation rate of 0.1 µg/cm2/min. Methanol and ethanol showed permeation at 1 min and 30 min elapsed, respectively. Hence, the gloves tested in this study exhibited permeation resistance to various chemical substances, and can thus be used in many work processes. Some film materials have short permeation time against certain chemical substances, but the chemical protective gloves tested in this study can be used at work sites, such as manufacturing sites, that require permeation resistance to different chemical substances.

Ultrathin Two-Dimensional Porous Fullerene Membranes for Ultimate Organic Solvent Separation.

Two-dimensional (2D) materials with high chemical stability have attracted intensive interest in membrane design for the separation of organic solvents. As a novel 2D material, polymeric fullerenes (C60)∞ with distinctive properties are very promising for the development of innovative membranes. In this work, we report the construction of a 2D (C60)∞ nanosheet membrane for organic solvent separation. The pathways of the (C60)∞ nanosheet membrane are constructed by sub-1-nm lateral channels and nanoscale in-plane pores created by the depolymerization of the (C60)∞ nanosheets. Attributing to ordered and shortened transport pathways, the ultrathin porous (C60)∞ membrane is superior in organic solvent separation. The hexane, acetone, and methanol fluxes are up to 1146.3±53, 900.4±41, and 879.5±42 kg ⋅ m-2 ⋅ h-1, respectively, which are up to 130 times higher than those of the state-of-the-art membranes with similar dye rejection. Our findings demonstrate the prospect of 2D (C60)∞ as a promising nanofiltration membrane in the separation of organic solvents from macromolecular compounds such as dyes, drugs, hormones, etc.

Ultralight and Robust Covalent Organic Framework Fiber Aerogels.

Shaping covalent organic frameworks (COFs) into macroscopic objects with robust mechanical properties and hierarchically porous structure is of great significance for practical applications but remains formidable and challenging. Herein, a general and scalable protocol is reported to prepare ultralight and robust pure COF fiber aerogels (FAGs), based on the epitaxial growth synergistic assembly (EGSA) strategy. Specifically, intertwined COF nanofibers (100-200 nm) are grown in situ on electrospinning polyacrylonitrile (PAN) microfibers (≈1.7 µm) containing urea-based linkers, followed by PAN removal via solvent extraction to obtain the hollow COF microfibers. The resultant COF FAGs possess ultralow density (14.1-15.5 mg cm-3 ) and hierarchical porosity that features both micro-, meso-, and macropores. Significantly, the unique interconnected structure composed of nanofibers and hollow microfibers endows the COF FAGs with unprecedented mechanical properties, which can fully recover at 50% strain and be compressed for 20 cycles with less than 5% stress degradation. Moreover, the aerogels exhibit excellent capacity for organic solvent absorption (e.g., chloroform uptake of >90 g g-1 ). This study opens new avenues for the design and fabrication of macroscopic COFs with excellent properties.