Porous Properties Research Articles

Production of Porous Biochar from Cow Dung Using Microwave Process.

To valorize livestock manure, the present study investigated the production of biochar from cow dung (CD) by microwave pyrolysis. The pore properties and chemical characteristics of CD and CD-based biochar products were found to correlate with the process parameters like microwave power (300-1000 W) and residence time (5-20 min). The findings indicated that CD is an excellent biomass based on the richness of lignocellulosic constituents from the results of proximate analysis and thermogravimetric analysis (TGA). Higher calorific values were obtained at mild microwave conditions, giving the maximal enhancement factor 139% in comparison with the calorific value of CD (18.97 MJ/kg). Also, it can be concluded that the biochar product obtained at 800 W for a holding time of 5 min had the maximal BET surface area of 127 m2/g and total pore volume of 0.104 cm3/g, which were microporous and mesoporous in the nitrogen adsorption-desorption adsorption analysis. On the other hand, the CD-based biochar contained oxygen-containing functional groups and inorganic minerals based on the spectroscopic analyses by Fourier-transform infrared spectroscopy (FTIR) and energy-dispersive X-ray spectroscopy (EDS), thus featuring to be prone to hydrophilicity in aqueous solutions.

A General Synthesis of Nanostructured Conductive Metal-Organic Frameworks from Insulating MOF Precursors for Supercapacitors and Chemiresistive Sensors.

Two-dimensional conjugated metal-organic frameworks (2D c-MOFs) are emerging as a unique subclass of layer-stacked crystalline coordination polymers that simultaneously possess porous and conductive properties, and have broad application potential in energy and electronic devices. However, to make the best use of the intrinsic electronic properties and structural features of 2D c-MOFs, the controlled synthesis of hierarchically nanostructured 2D c-MOFs with high crystallinity and customized morphologies is essential, which remains a great challenge. Herein, we present a template strategy to synthesize a library of 2D c-MOFs with controlled morphologies and dimensions via insulating MOFs-to-c-MOFs transformations. The resultant hierarchically nanostructured 2D c-MOFs feature intrinsic electrical conductivity and higher surface areas than the reported bulk-type 2D c-MOFs, which are beneficial for improved access to active sites and enhanced mass transport. As proof-of-concept applications, the hierarchically nanostructured 2D c-MOFs exhibit a superior performance for electrical properties related applications (hollow Cu-BHT nanocubes-based supercapacitor and Cu-HHB nanoflowers-based chemiresistive gas sensor), achieving over 225 % and 250 % improvement in specific capacity and response intensity over the corresponding bulk type c-MOFs, respectively.

Eine allgemeine Strategie zur Synthese von nanostrukturierten leitfähigen MOFs aus isolierenden MOF‐Vorläufern für Superkondensatoren und chemiresistive Sensoren

AbstractZweidimensionale konjugierte metallorganische Gerüstverbindungen (2D c‐MOFs) entwickeln sich zu einer einzigartigen Unterklasse von geschichteten kristallinen Koordinationspolymeren, die gleichzeitig Porosität und elektrische Leitfähigkeit besitzen und ein breites Anwendungspotenzial in Energiespeicherung und elektronischen Geräten haben. Um die intrinsischen elektronischen Eigenschaften und strukturellen Besonderheiten von 2D c‐MOFs optimal nutzen zu können, ist die kontrollierte Synthese von hierarchisch nanostrukturierten 2D c‐MOFs mit hoher Kristallinität und maßgeschneiderten Morphologien unerlässlich, was eine große Herausforderung darstellt. In diesem Artikel stellen wir eine Template‐Strategie zur Synthese einer Bibliothek von 2D c‐MOFs mit kontrollierten Morphologien und Dimensionen über eine Transformation von isolierenden MOFs zu c‐MOFs vor. Die daraus resultierenden hierarchisch nanostrukturierten 2D c‐MOFs weisen höhere intrinsische elektrische Leitfähigkeiten und größere Oberflächen als die literaturbeschriebenen 2D c‐MOFs auf, was für einen verbesserten Zugang zu aktiven Seiten und einen verbesserten Massentransport von Vorteil ist. Als Proof‐of‐Concept‐Anwendungen zeigen die hierarchisch nanostrukturierten 2D c‐MOFs eine überlegene Leistung für Anwendungen welche auf ihren elektrischen Eigenschaften basieren (hohle Cu‐BHT‐Nanowürfel‐basierte Superkondensatoren und Cu‐HHB Nanoblumen‐basierte chemiresistive Gassensoren). Diese erreichen eine Verbesserung der spezifischen Kapazität und der Ansprechintensität von über 225 % bzw. 250 % gegenüber den entsprechenden durch Bulk‐Synthese erhaltenen c‐MOFs.

Crystal structures and syntheses of four novel Cu(I)-MOFs with in-situ reduced of Cu(II) and highly efficient fluorescent sensor for trace nitroaromatics

Four novel Cu(I)-based metal-organic frameworks, [Cu3(p-IPIB)(CN)Cl2]n (Cu(I)-MOF-7), [Cu3(p-IPIB)(CN)Cl2]n (Cu(I)-MOF-8), [Cu3(p-IPIB)Cl3]n (Cu(I)-MOF-9) and [Cu2(p-IPIB-Cl)1/2Cl2(H2O)]n (Cu(I)-MOF-10) where ligand p-IPIB is 1,4-bis[(2-(4-(1H-imidazol -1-yl)-phenyl)-1H-imidazole-1-yl)-methyl]-benzene, have been successfully synthesized by in-situ reduction of Cu(II) under solvothermal reaction condition. Single X-ray diffraction analysis shown that Cu(I)-MOF-7 and 8 are not only structural supramolecular isomerism containing cyano-bridge which was in situ obtained from the cleavage of the CCN bond of acetonitrile solvent, but also a 3D twofold interpenetration metallo-supramolecular assembly for Cu(I)-MOF-7 and a 3D porous supramolecular assembly containing the macrometallacyclic box structure for Cu(I)-MOF-8, respectively. Cu(I)-MOF-9 is a 1D channel polymeric chain motif with macrometallacyclic structure containing [Cu3Cl3] cluster of μ3- and μ2-chloride bridge. And Cu(I)-MOF-10 is also a 3D twofold interpenetration metallo-supramolecular assembly with [Cu4Cl3(H2O)2] cluster of μ4-chloride bridge. They are thermally stable and exhibit apparent porous properties with adsorption of N2 and CO2 gas. The fluorescence sensing experiment indicated that Cu(I)-MOF 7–10 can be used for detecting nitroaromatic explosives through fluorescence quenching in the solution and they have the best sensing effects on the detection of 2,4,6-Trinitrophenol (TNP). Especially, Cu(I)-MOF-9 has the best sensing property towards TNP with a higher quenching constant of 4.53 × 104 L/mol and a lower detection limit of 1.21 ppm.

Investigating Fe-doped yttrium oxide nanophosphors for enhanced latent fingerprint visualization and deep learning analysis

In the study, synthesized Fe3+ doped yttrium oxide nanophosphors (Y2O3:Fe NPs, 1–11 mol%), including structural, microstructural, chemical state, optical, thermal, and photoluminescence properties, are extensively studied. An optimized 7 mol % Fe doped Y2O3 NPs powder is used to develop latent fingerprints on various surfaces through a simple powder dusting method. The developed fingerprints are visible under 254 nm UV light. The research also analyzes several pore properties: size, shape, number, position, type, and inter-distance. A fingerprint recognition deep learning model based on the YoLOv8 algorithm was developed and employed for analyzing both single and overlapped fingerprints. These highly effective NPs are also used to create a transparent anti-counterfeiting (AC) ink that exhibits AC properties when exposed to UV light, and their physical and chemical stability opens novel applications in the AC field. The optimized Y2O3:7Fe3+ NPs are an excellent luminous platform for solid-state lighting, AC, and dermatoglyphics applications.

Synthesis and application of modified membranes for efficient cationic and anionic dye elimination

This study focuses on developing ceramic ultrafiltration membranes using locally sourced kaolin clay and feldspar. An active layer composed of graphene and alkoxide is added to enhance the performance of these clay supports. This layer is thin, porous, and can vary in thickness. The support and filter layer's porous properties are characterized using SEM, DRX, ATG/ATD, XPS, and FTIR techniques. Filtration tests are conducted on modified porous tubular supports using cationic and anionic dye solutions. The filtration is performed tangentially at a pressure of 3.5 bar and a processing time of 120 minutes. The retention rates of the colored solutions are measured using a UV-visible spectrophotometer. The results show a 100% retention rate for supranol yellow and orange II at a concentration of 10-4 M, while for crystal violet and malachite green, the retention rates are 92.03% and 95.30%, respectively.

Alternating current assisted preparation of three-dimensional graphene aerogels and the application in electromagnetic interference shielding

Three-dimensional (3D) graphene aerogels (GA) have obtained significant attention across various fields due to their lightweight and porous properties. Nevertheless, the development of a scalable and environmentally friendly method for synthesizing self-supported 3D GA remains a challenge. In this study, we introduced an innovative method for the preparation of 3D GA using alternating current (AC) strategy, which fully used the characteristic of AC's constantly changing current direction to attract graphene oxide (GO) particles to the electrode surface and subsequently reduced them to reduced GO (rGO). Ultimately, GA is self-assembled on the electrode surface under repeated cycles. An applied AC signal with optimal parameters produced a porous GA with an oxygen content of 10.76 at%, which is 66.67% less than that of the original GO. When applying GA to electromagnetic interference (EMI) shielding, it provides a maximum specific shielding effectiveness of 9100 dB cm2 g−1 at X-band due to the repeated reflection and absorption of electromagnetic waves (EMWs) by the abundant pore wall. Furthermore, the shielding effectiveness can be significantly improved to 68.60 dB at the X-band for a multilayer GA. Notably, it is worth emphasizing that this AC-assisted synthesis method has proven its adaptability to various metal electrodes, such as cost-effective iron and copper. Importantly, this method avoids the high-temperature treatments and the use of environmentally hazardous chemicals. It is envisaged that this environmentally friendly and low-cost approach will greatly facilitate the cost-effective production of 3D GA with diverse applications.

Task specific microextraction column based on monolith for magnetic field-assisted in-tube solid phase microextraction of vanadium species in complex samples prior to online chromatographic analysis

The dominant species of vanadium (V) are V(IV) and V(V) which exhibit different toxicity and biological effects. Thus, speciation of V(IV) and V(V) is highly essential. Efficient sample preparation is the core step in the quantification of V(IV) and V(V). In the present study, a new task specific microextraction column based on monolith mingled with Fe3O4 nanoparticles (MBMC) was in situ synthesized in capillary and utilized as the extraction phase of magnetic field-assisted in-tube solid phase microextraction (MA-IT-SPME) of V(IV) and V(V) species which were coordinated with ethylene diamine tetraacetic acid (EDTA). The prepared MBMC presented porous and superparamagnetic properties, and possessed abundant functional groups. Results revealed that the exertion of magnetic field during adsorption and eluting steps boosted the extraction efficiency of V(IV)-EDTA and V(V)-EDTA chelates from 65.1 % to 55.7 %–90.0 % and 80.1 %, respectively. Under the beneficial extraction parameters, the established MA-IT-SPME was online hyphenated with HPLC/DAD to perform speciation of trace vanadium in water and vegetable samples, the achieved limits of detection were 0.054–0.060 μg/L and 1.4–1.5 μg/kg in water and vegetable samples, respectively, and the spiked recoveries varied from 82.5 to 118 %. In addition, relevant extraction mechanism under magnetic field was explored. In comparison with existing methods, the developed MA-IT-SPME technique displays some attractive merits such as automation, good anti-interference ability, high extraction efficiency, low cost and less use of organic solvent, in the capture of V species. The established online MBMC@MA-IT-SPME-HPLC/DAD system can become a competitive approach for sensitive speciation of V(IV) and V(V) at trace levels in complex samples.

Heat transfer mechanism of TiO2-doped silica aerogel

The remarkable thermal insulation properties of silica aerogel stem from its distinctive three-dimensional nano-network structure, rendering it a promising candidate for diverse applications such as energy-efficient construction and aerospace engineering, among others. Nonetheless, the application of pure silica aerogels at high temperatures is limited due to their nearly transparent nature in the wavelength range of 2–8 µm. To overcome this limitation, the incorporation of opacifiers into pure silica aerogels can effectively augment the overall extinction coefficient of the material, consequently minimizing radiative heat transfer. In this paper, titanium dioxide is used to improve the high-temperature thermal insulation performance of silica aerogels. In order to fully understand the internal heat transfer properties of silica aerogel-based composites theoretically and to provide guidance for the structural design of high-temperature insulation materials, a theoretical model is established. This model accounts for the actual microstructure of the materials as well as the porous structural properties of the secondary particles in silica aerogel. Furthermore, it considers the intricate nature of heat transfer in multiphase hybrid materials. This paper compares the predictions of the model with experimental data. The results show that the theoretical model can quickly and accurately predict the thermal conductivity of TiO2-doped silica aerogels, and the error is controlled within 8 %, with a minimum error of 1.1 %.

Degradation of norfloxacin by red mud-based prussian blue activating H2O2: A strategy for treating waste with waste

The massive accumulation of red mud (RM) and the abuse of antibiotics pose a threat to environment safety and human health. In this study, we synthesized RM-based Prussian blue (RM-PB) by acid solution-coprecipitation method to activate H2O2 to degrade norfloxacin, which reached about 90% degradation efficiency at pH 5 within 60 min and maintained excellent catalytic performance over a wide pH range (3−11). Due to better dispersion and unique pore properties, RM-PB exposed more active sites, thus the RM-PB/H2O2 system produced more reactive oxygen species. As a result, the removal rate of norfloxacin by RM-PB/H2O2 system was 8.58 times and 2.62 times of that by RM/H2O2 system and PB/H2O2 system, respectively. The reactive oxygen species (ROS) produced in the degradation process included ·OH, ·O2- and 1O2, with 1O2 playing a dominant role. The formation and transformation of these ROS was accompanied by the Fe(III)/Fe(II) cycle, which was conducive for the sustained production of ROS. The RM-PB/H2O2 system maintained a higher degradation efficiency after five cycles, and the material exhibited strong stability, with a low iron leaching concentration. Further research showed the degradation process was less affected by Cl-, SO42-, NO3-, and humic acids, but was inhibited by HCO3- and HPO42-. In addition, we also proposed the possible degradation pathway of norfloxacin. This work is expected to improve the resource utilization rate of RM and achieve treating waste with waste.

Effect of Post-Washing on Textural Characteristics of Carbon Materials Derived from Pineapple Peel Biomass.

Porous carbon materials have been widely used to remove pollutants from the liquid-phase streams. However, their limited pore properties could be a major problem. In this work, the effects of post-washing methods (i.e., water washing and acid washing) on the textural characteristics of the resulting biochar and activated carbon products from pineapple peel biomass were investigated in the carbonization and CO2 activation processes. The experiments were set at an elevated temperature (i.e., 800 °C) holding for 30 min. It was found that the enhancement in pore property reached about a 50% increase rate, increasing from 569.56 m2/g for the crude activated carbon to the maximal BET surface area of 843.09 m2/g for the resulting activated carbon by water washing. The resulting activated carbon materials featured the microporous structures but also were characteristic of the mesoporous solids. By contrast, the enhancement in the increase rate by about 150% was found in the resulting biochar products. However, there seemed to be no significant variations in pore property with post-washing methods. Using the energy dispersive X-ray spectroscopy (EDS) and the Fourier Transform infrared spectroscopy (FTIR) analyses, it showed some oxygen-containing functional groups or complexes, potentially posing the hydrophilic characters on the surface of the resulting carbon materials.

Effect of CO2 on HCl removal from syngas using normal and modified Ca-based hydrotalcites: A comparative study

MSW pyrolysis and gasification technologies have been recognized as effective means to enhance the resource utilization of MSW and promote a circular economy. However, the presence of HCl gas can significantly impact the quality and application of syngas. To maximize syngas resource utilization, develop highly efficient HCl adsorbent, this study investigates the performance and mechanism of HCl removal from syngas using a conventional hydrotalcite (Mg-Al-CO3) and modified Ca-based hydrotalcite (Ca-Mg-Al-CO3). The impact of CO2, a component naturally presents in syngas, on the performance of both materials, were also investigated. Characterization techniques, including XRD, TGA, SEM, and analysis of pore properties and specific surface area, were employed to understand the underlying reaction mechanism. The results demonstrated that the performance of Ca-Mg-Al-CO3 was significantly superior to that of conventional Mg-Al-CO3 sorbents, particularly in the presence of CO2 However, the presence of CO2 had a detrimental impact on the performance of Ca-Mg-Al-CO3 in HCl removal, and this effect became increasingly pronounced with higher concentrations of CO2. TGA results revealed a competitive relationship between HCl and CO2 during the adsorption process. Additionally, the fitting results of adsorption kinetics suggested that the adsorption reaction of HCl and CO2 by Ca-Mg-Al-CO3 followed multiple rate-controlling mechanisms.

Digital Cake Analysis: A Novel Coal Filter Cake Examination Technique Using Microcomputed Tomography

Filtration is crucial for separating solids and liquids in various industries. Understanding slurry properties and filter cake structures is essential for optimising filtration performance. Conventional methods focus on interpreting filtration data to improve the understanding of filtration mechanisms. However, examining fragile filter cakes is challenging, and current techniques often alter their structure. Conventional methods only provide an average representation of cake porosity, neglecting variations in porosity and pore distribution across the cake thickness. This study introduces the Digital cake analysis, a non-destructive technique for evaluating filter cake structure. Filtration experiments using a custom-built unit were conducted on coal slurries to obtain filter cake samples. X-ray-microcomputed tomography (µCT) imaging was utilized for cake analysis. Image enhancement techniques were employed to improve the quality of the µCT images. The enhanced images were segmented into three phases (resolved pore, subresolution pore, and solid phases) for quantitative analysis. This segmentation technique allocated partial pore volume to voxels in the subresolution phase based on their intermediate grey-scale intensity, enabling more accurate porosity calculations. Unlike conventional methods, this approach computed porosity values for resolved (100% void) and subresolution (partially void) pores. This image segmentation technique facilitated accurate computations of porosity, pore size distribution, and pore properties, significantly advancing the understanding of cake structures. Digital cake analysis produced porosity measurements similar to the experimental results.

Effect of variable viscosity, porous walls and mixed thermal boundary condition on the onset of Rayleigh-Bénard convective instability

In this paper, we have studied the criteria for the onset of instability in the Rayleigh-Bénard convection problem, by considering a fluid layer confined between two infinitely extended rough boundaries, which are subjected to mixed-type thermal boundary conditions, physically representing the imperfectly conducting boundaries. The rough boundaries are assumed to be shallow porous layers with different pore size, properties, and permeabilities. Mathematically, it is given by the Saffman type boundary condition. Therefore, we have two generalized forms of boundary conditions, one for the flow field and the other for the thermal field. The two limiting cases of the mixed-type thermal boundary condition correspond to a perfectly conducting boundary and to a perfectly insulating boundary, whereas the two limiting cases of the hydrodynamic boundary condition correspond to a no-slip condition and to a free-surface condition, depending upon the limiting values of the parameters involved in these two generalized boundary conditions. The linear and nonlinear energy stability analyses are performed, and the existence of the region of subcritical instability is checked. Through the principle of exchange of stability analysis, it is found that the instability occurs only in the stationary mode. The adiabatic boundary condition is found to be more restrictive than the isothermal boundary condition. Under given conditions, the instability is observed to be occurring in the infinite wavelength mode for the case of adiabatic boundaries. In the present work, the effect of temperature and pressure dependent viscosity on the stability of the system has been shown and found to be of destabilizing nature. However, the roughness of the boundaries is found to be of stabilizing nature.

Hybrid mesoporous silica materials templated with surfactant polyion complex (SPIC) micelles for pH-triggered drug release

New Surfactant PolyIon Complex (SPIC) micelles were assembled by electrostatic complexation of an antibacterial cationic surfactant, cetylpyridinium chloride (CPC), and a double hydrophilic block copolymer (DHBC) containing a neutral comb block of poly(oligo(ethylene glycol)) methyl ether acrylate (PEOGA) and a weak polyacid block of poly(acrylic acid) (PAA). The corresponding SPIC micelles, with a CPC/PAA core and a PEOGA corona, were successfully used as structure directing and functionalizing agents in a soft and sustainable sol-gel strategy, yielding hybrid mesoporous silica (MS) materials with a monomodal pore size distribution centred at 2.8 nm. The influence of synthesis parameters, including the pH, concentrations and ratios of components, was systematically investigated. The obtained hybrid MS materials were intrinsically functional, with PEOGA blocks anchored in silica walls via H-bonding, while weak polyacid blocks, complexed with CPC, were confined within the mesopores. The response of the materials to pH changes (pH 7.4, 4.2 and 3) indicated remarkable stability of the anchored DHBC, while CPC was selectively released under the acidic conditions typical of orodental biofilm microenvironments. This result is noteworthy, since the release of encapsulated amphiphilic drugs into water is less favorable than that of hydrophilic drugs. Owing to the control of their pore and functionality properties, ordered hybrid silica materials templated and functionalized with SPIC systems will be materials of choice for developing pH-responsive biomedical devices using wet processing techniques.

Harnessing the potential of modified cellulosic pumpkin seed hulls as affordable biosorbents for cationic dye removal from aqueous solutions: adsorption kinetics and isotherm studies

AbstractThis investigation focuses on examining the adsorption behavior of crystal violet dye on cellulose (CS) and its modified forms, including cellulose loaded with nicotinic acid (CSN) and cellulose loaded with thiourea (CST). Batch experiments were performed to analyze the adsorption process, while various characterization techniques, such as Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), Brunauer–Emmett–Teller (BET), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA), were utilized to assess the structural and morphological changes in the cellulose materials. The findings reveal that the adsorption process follows a pseudo-second-order kinetic model, indicating a chemical adsorption mechanism. Additionally, the Langmuir isotherm model suggests monolayer adsorption on cellulose surfaces. Thermodynamic analysis demonstrates that the adsorption process is spontaneous and exothermic for CS and CSN, whereas it is endothermic for CST. The characterization techniques employed provide valuable insights into the structural modifications and porous properties of cellulose materials. Overall, this study underscores the potential of modified cellulose materials to effectively remove dyes in wastewater treatment applications. Notably, thiourea-loaded cellulose CST exhibits superior adsorption capacity with removal percentages of 78.2% compared to CS and CSN, whose removal percentages were 76.45% and 76.72%, respectively, suggesting the promising role of CST in dye removal. These findings contribute to a comprehensive understanding of crystal violet dye adsorption on cellulose and its modified forms, thereby paving the way for future research on the application of modified cellulose materials in wastewater treatment processes.

A pore network-based multiscale coupled model for rapid permeability prediction of tight sandstone gas

Tight sandstone has multiscale pore structures. Gas transport in tight sandstones involves several length scales and the complicated physics. Gas transport characteristics in tight sandstone can be represented by apparent gas permeability. Microstructure-based accurate and efficient calculation of gas permeability is challenging. By combining CT and SEM images along with statistical analysis, we present a novel pore network-based multiscale coupled model (MCPNM) to rapidly predict the apparent gas permeability. CT images are adopted to extract the large-scale pore network (LPNM) and the clay component, and SEM image is used to get the properties of small-scale pores. Upscaled model (UM) of small-scale pores is built via statistical analysis and then assigned to the clay domains. The LPNM and UM are coupled as MCPNM by the cross-scale connection structure with variable diameter. The pore spaces at several length scales and the flow characteristics in them are included in the MCPNM. We validate the MCPNM by comparing the calculated apparent gas permeability to the results of available multiscale pore network models and the experimental data. Compared with the available multiscale pore network models, MCPNM solves the accuracy/efficiency trade-off of tight gas permeability prediction. The effects of pressure, temperature, and gas type on gas permeability are studied. The MCPNM simplifies the permeability calculation process and can accurately and rapidly predict tight sandstone gas permeability.

Enhancing Structure-Property Relationships in Porous Materials through Transfer Learning and Cross-Material Few-Shot Learning.

Porous materials have emerged as promising solutions for a wide range of energy and environmental applications. However, the asymmetric development in the field of metal-organic frameworks (MOFs) has led to a data imbalance when it comes to MOFs versus other porous materials such as covalent organic frameworks (COFs), porous polymer networks (PPNs), and zeolites. To address this issue, we introduce PMTransformer (Porous Material Transformer), a multimodal Transformer model pretrained on a vast data set of 1.9 million hypothetical porous materials, including metal-organic frameworks, covalent organic frameworks, porous polymer networks, and zeolites. PMTransformer showcases remarkable transfer learning capabilities, resulting in state-of-the-art performance in predicting various porous material properties. To address the challenge of asymmetric data aggregation, we propose cross-material few-shot learning, which leverages the synergistic effect among different porous material classes to enhance the fine-tuning performance with a limited number of examples. As a proof of concept, we demonstrate its effectiveness in predicting band gap values of COFs using the available MOF data in the training set. Moreover, we established cross-material relationships in porous materials by predicting the unseen properties of other classes of porous materials. Our approach presents a new pathway for understanding the underlying relationships among various classes of porous materials, paving the way toward a more comprehensive understanding and design of porous materials.

Effect of heating self-healing and construction of composite structure on corrosion resistance of superhydrophobic phosphate ceramic coating in long-term water environment

Despite superhydrophobic ceramic coatings have been successfully prepared, there lacks an improvement in their corrosion resistance in long-term saltwater environments due to the porous properties. In this paper, two coatings were prepared again by heat repair treatment and construction of double-layer composite structure, and the surface characteristics of the coatings were determined by scanning electron microscope, infrared spectrometer and contact angle measuring instrument, and the electrochemical performance and corrosion resistance of the coatings were evaluated by electrochemical test and immersion test. The results showed that the original porous ceramic coating had superhydrophobic property, and the water contact angle (CA) and sliding angle (SA) were 150.4°and 8.7°, respectively. Through knife scratching, sandpaper abrasion and tape peeling tests, the coating had good bond strength and mechanical durability. Compared with the original coating, the corrosion resistance of heat repair coating and composite coating had better corrosion resistance and a protective effect on the substrate. This protective mechanism can be attributed to the repair effect of heat treatment on the hydrophobicity of the coating, and the composite structure resists the penetration of external liquids. Based on these results, heat repair and double-layer composite structures can improve the defects of long-term insufficient durability of superhydrophobic ceramic coatings, which have potential marine application prospects.

A single shell protein plays a major role in choline transport across the shell of the choline utilization microcompartment of Escherichia coli 536.

Bacterial microcompartments (MCPs) are widespread protein-based organelles that play important roles in the global carbon cycle and in the physiology of diverse bacteria, including a number of pathogens. MCPs consist of metabolic enzymes encapsulated within a protein shell. The main roles of MCPs are to concentrate enzymes together with their substrates (to increase reaction rates) and to sequester harmful metabolic intermediates. Prior studies indicate that MCPs have a selectively permeable protein shell, but the mechanisms that allow selective transport across the shell are not fully understood. Here we examine transport across the shell of the choline utilization (Cut) MCP of Escherichia coli 536, which has not been studied before. The shell of the Cut MCP is unusual in consisting of one pentameric and four hexameric bacterial microcompartment (BMC) domain proteins. It lacks trimeric shell proteins, which are thought to be required for the transport of larger substrates and enzymatic cofactors. In addition, its four hexameric BMC domain proteins are very similar in amino acid sequence. This raises questions about how the Cut MCP mediates the selective transport of the substrate, products and cofactors of choline metabolism. In this report, site-directed mutagenesis is used to modify the central pores (the main transport channels) of all four Cut BMC hexamers to assess their transport roles. Our findings indicate that a single shell protein, CmcB, plays the major role in choline transport across the shell of the Cut MCP and that the electrostatic properties of the CmcB pore also impact choline transport. The implications of these findings with regard to the higher-order structure of MCPs are discussed.