Average Pore Size Research Articles

Synergistic Effects of Polydopamine/Medical Stone Bio-Adsorbents for Enhanced Interfacial Adsorption and Dynamic Filtration of Bacteria.

Polymer-based wastewater disinfection, which is typically performed using chemical oxidation or irradiation, can result in various toxic byproducts and corrosion under harsh environments. This study introduces a robust bio-adsorbent prepared from naturally abundant polydopamine-modified medical stone (MS@PDA) for the high-efficiency removal of bacteria from water. The PDA nanocoating can be easily applied through an in situ self-polymerization process, resulting in a considerably high bacterial adsorption capacity of 6.6 k pcs mm-2 for Staphylococcus aureus. A cyclic flow-through dynamic filtration and a disinfection system was implemented using an MS@PDA porous filter with an average pore size of 21.8 ± 1.4 µm and porosity of ~83%, achieving a 5.2-6.0-fold enhancement in the cumulative removal efficiency for MS@PDA2. The underlying mechanisms were elucidated through the synergistic effects of interfacial bio-adsorption and size-dependent interception. Notably, the bacteria captured on the surface could be killed using the enhanced photothermal effects of the PDA nanocoating and the inherent antimicrobial properties of the mineral stone. Thus, this study not only provides a new type of advanced bio-adsorbent but also provides new perspectives on an efficient and cost-effective approach for sustainable wastewater treatment.

Enhancing melt foam stability, form-filling process, and pore structure evolution of shaped aluminum foam

This study explores the stability of Al–Si–Ca–Mg-Sc melt foams and investigates the melt foam filling process and the dynamic evolution of pore structures in the fabrication of foam aluminum profiles using the melt transfer foaming technique. The results show that Al–Si–Ca–Mg-Sc melt foam maintains high porosity and a stable pore structure even after 30 min of foaming, without any signs of boundary rupture or destabilization. This stability is attributed to the increased viscosity from finely dispersed second-phase particles, which hinder the growth, coalescence, and drainage of the melt foam. Regarding melt foam filling, enhanced filling capability is achieved by elevating the foaming temperature, extending the foaming time, and increasing the TiH2 addition. The melt foam exhibits a smooth flow from the lower part of the mold to the corners, completing the filling process with well-defined edges in the profile. During lateral movement for filling, a gradual increase in porosity, a decrease in pore number, and a slow enlargement of pore size and standard deviation along the lateral (x-axis) are observed. This is due to the slower liquid phase flow compared to the gas phase, resulting in bubble coalescence. After filling is complete, this phenomenon improves, contributing to a slow and stable evolution of the pore structure.Under optimized conditions of 1.4 wt% TiH2 addition at 600°Cfor 9 min of foaming with Al–Si–Ca–Mg-Sc alloy melting, we successfully fabricated foam aluminum profiles with complete filling, a porosity of 81.5%, an average pore size of 2–3 mm, and a uniform pore structure.

Exploring the Relationship Between Biochar Pore Structure and Microbial Community Composition in Promoting Tobacco Growth.

The potential benefits of biochar, a carbon-rich substance derived from biomass, for enhancing agricultural yield and soil health have drawn increasing interest. Nevertheless, owing to the lack of specialized studies, the role of its poly-spatial structure in the success of fostering plant growth remains unclear. This study aimed to assess the effects of various biochar pore shapes on tobacco growth and the underlying microbiological processes. Three pyrolysis temperatures (250 °C, 400 °C, and 550 °C) were used to produce biochar from tobacco stems, resulting in different pore structures (T3 > T2 > T1). We then used BET-specific surface area (BET), t.Plot micropore specific surface area (t.Plot), mesopore specific surface area (MSSA), specific pore volume (SPV), average pore size (AP), and mesopore pore volume (MPV) measurements to evaluate the effects of these biochars on tobacco growth and biomass accumulation, and microbial analyses were performed to investigate the underlying mechanisms. When applied to plants, biochar increased their growth compared to untreated controls. The most notable improvement in tobacco growth was observed in the biochar produced at 400 °C (T3), which possessed the largest and most advantageous pore structure among all treatments. Further studies demonstrated that biochars with greater specific surface areas (BET, t.Plot, and MSSA) positively altered the abundance of key microbial taxa (e.g., Stenotrophobacter, Ensifer, Claroideoglomus) and community composition, thereby encouraging plant development and biomass accumulation. Conversely, greater pore volumes (SPV, AP, and MPV) inhibited microbial activity and significantly affected growth and biomass accumulation. Structural equation modeling further demonstrated that the pore structure of biochar greatly affected plant growth by changing the relative abundance and community composition of soil microbes. Maximizing the benefits of biochar in stimulating plant growth and improving soil microbial communities depends on optimizing the material's pore structure, particularly by increasing the specific surface area. These findings will help expand the use of biochar in sustainable agriculture.

Optimization of Hydrogen Utilization and Process Efficiency in the Direct Reduction of Iron Oxide Pellets: A Comprehensive Analysis of Processing Parameters and Pellet Composition

The article deals with the H2 consumption for different processing conditions and the composition of the processed pellets during the direct reduction process. The experiments are carried out at 600–1300 °C, with gas pressures of 1–5 bar, gas flow rates of 1–5 L min−1, and basicity indices of 0 to 2.15. Pellets with different compositions of TiO2, Al2O3, CaO, and SiO2 are analyzed. The gas flow rate is crucial, with 0–10 L min−1 leading to an H2 consumption of 0–5.1 kg H2/kg pellet. The gas pressure (0–10 bar) increases the H2 consumption from 0 to 5.1 kg H2/kg pellet. Higher temperatures (600–1300 °C) reduce H2 consumption from 5.1 to 0 kg H2/kg pellet, most efficiently at 950–1050 °C, where it decreases from 0.22 to 0.10 kg H2/kg pellet. An increase in TiO2 content from 0% to 0.92% lowers H2 consumption from 0.22 to 0.10 kg H2/kg pellet, while a higher Fe content (61–67.5%) also reduces it. An increase in SiO2 content from 0% to 3% increases H2 consumption from 0 to 5.1 kg H2/kg pellet. Porosity structure influences H2 consumption, with the average pore size decreasing from 2.83 to 0.436 mm with increasing TiO2 content, suggesting that micropores increase H2 consumption and macropores decrease it.

An Easy-to-Handle Route for Bicomponent Porous Tubes Fabrication as Nerve Guide Conduits

Over the past two decades, the development of nerve guide conduits (NGCs) has gained much attention due to the impellent need to find innovative strategies to take care of damaged or degenerated peripheral nerves in clinical surgery. In this view, significant effort has been spent on the development of high-performance NGCs by different materials and manufacturing approaches. Herein, a highly versatile and easy-to-handle route to process 3D porous tubes made of chitosan and gelatin to be used as a nerve guide conduit were investigated. This allowed us to fabricate highly porous substrates with a porosity that ranged from 94.07 ± 1.04% to 97.23 ± 1.15% and average pore sizes—estimated via X-ray computed tomography (XCT) reconstruction and image analysis—of hundreds of microns and an irregular shape with an aspect ratio that ranged from 0.70 ± 0.19 to 0.80 ± 0.15 as a function of the chitosan/gelatin ratio. More interestingly, the addition of gelatin allowed us to modulate the mechanical properties, which gradually reduced the stiffness—max strength from 0.634 ± 0.015 MPa to 0.367 ± 0.021 MPa—and scaffold toughness—from 46.2 kJ/m3 to 14.0 kJ/m3—as the gelatin content increased. All these data fall into the typical ranges of the morphological and mechanical parameters of currently commercialized NGC products. Preliminary in vitro studies proved the ability of 3D porous tubes to support neuroblastoma cell (SH-SY5Y) adhesion and proliferation. In perspective, the proposed approach could also be easily implemented with the integration of other processing techniques (e.g., electrospinning) for the design of innovative bi-layered systems with an improved cell interface and molecular transport abilities.

Microstructure, thermal, and mechanical properties of hierarchical porous silicon carbide made by direct ink writing

AbstractHierarchical porous silicon carbide (SiC) ceramics were fabricated by combining particle‐stabilized emulsions and three‐dimensional (3D) printing. Direct ink writing (DIW) was used as the 3D printing technique. The formulation for successful printing is discussed in relation to the rheology of the emulsions. The SiC emulsions were able to be printed with a lower storage modulus (G′) and apparent yield shear stress (τy) than previously reported SiC ink pastes. The printed and sintered porous SiC ceramics possess a total porosity of 73.7% with an average pore size within the filaments of 2.2 µm in diameter. A hierarchical pore structure that contains pore sizes of about 250 µm, around 1–10 µm and smaller than 0.5 µm can be observed in the microstructure and pore size distribution. The mechanical properties showed a good strength‐to‐density ratio, and the thermal conductivity was reduced to 4.9 W/m·K. This study provides a new reliable approach for fabricating hierarchical porous SiC ceramics with low thermal conductivity.

Study on the Thermal Effect of Spontaneous Combustion of Coal-Based Activated Carbon By-Products Oxidized and Carbonized Powders

ABSTRACT To investigate the spontaneous combustion thermal effect of the by-products oxidized powder (OP) and carbonized powder (CP) produced during the preparation of coal-based activated carbon (CBAC). First, the changes in composition and pore structure of OP and CP compared with raw coal (RC) were measured by coal quality analysis and nitrogen adsorption experiments. The ability of OP and CP to physically adsorb oxygen was determined. Then, differential scanning calorimetry (DSC) was used to study the whole process thermal effect of the spontaneous combustion of OP and CP. Finally, the thermal effect of OP and CP during low-temperature oxidation process was further explored by the C80 micro-calorimeter, and the thermodynamic characteristics were also probed. The results show that the content of fixed carbon and carbon elements in OP and CP are significantly greater than that in RC, which makes the pore structure of both complicated. In addition, the total pore volume, average pore size, and specific surface area of OP and CP are greater than that of RC, which is more conducive to the physical adsorption of oxygen by both. No transition platform is caused by the decomposition of intermediate products on the DSC curve of CP. The characteristic temperatures of CP (except T D10) are lower than that of OP, indicating that the spontaneous combustion reaction of CP started earlier than that of OP. However, part of the combustible substance of CP was consumed in the dry distillation process, leading to the thermal release and maximum thermal release rate being smaller than that of OP. The apparent activation energy (E a) of stages H2 and H3 in the low-temperature oxidation process of OP is 75.04 and 11.42 kJ mol−1, while that of CP is 83.11 and 30.91 kJ mol−1. The threshold of CP entering stages H2 and H3 is higher than that of OP. Nevertheless, from the pre-exponential factor (A), the low-temperature oxidation process of CP is more rapid.

A grey relational analysis of the micro arc oxidation process parameters and their effects on Ti-6Al-7Nb coating performance and corrosion resistance for biomedical uses

Abstract In current investigation micro arc oxidation of Ti6Al7Nb alloy was done to improve its surface properties and corrosion resistance. Mixture of Na2SiO3, Na3PO412H2O and KOH is used as electrolyte. MAO treated Ti6Al7Nb specimens were examined using x-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and scanning electron microscopy (SEM) to examine their morphology and phase composition. It was observed that electrolyte composition is simultaneously included in the growing oxide layer during MAO process. From electrochemical study it was found that corrosion resistance of the Ti6Al7Nb increases during EIS testing in 0.9% NaCl solution. It was found that frequency, duty cycle, current and processing time effect the surface roughness, thickness, hardness and corrosion resistance of coating. Out of above mention parameters frequency and duty cycle has major impact on performance parameters. The objective of current investigation is to find out effects MAO process parameters on coating performance parameters such as coating thickness, hardness, surface roughness and corrosion resistance. At duty cycle of 50%, frequency 500 Hz, current 300 mA and processing duration 7.5 min, highest coating thickness 32.96 μm and surface roughness 3.3680 μm was obtained. Process parameters have the influence on pore size, biggest average pore size 3.8519 μm was obtained at duty cycle of 50%, frequency 500 Hz, current 300 mA and processing duration 7.5 min. Grey relational analysis is done to determine which process variable has the most influence on performance parameters. From grey relational analysis technique, it was observed that duty cycle 50%, frequency 500 Hz, current 300 mA, and processing time 7.5 min are ideal process parameters for higher coating thickness, hardness, surface roughness and better corrosion resistance. From grey relation analysis it was also found that frequency has most significant impact on performance parameters after that duty cycle, then current and at last processing time.

Dual-Self-Crosslinking Effect of Alginate-Di-Aldehyde with Natural and Synthetic Co-Polymers as Injectable In Situ-Forming Biodegradable Hydrogel.

Injectable, in situ-forming hydrogels, both biocompatible and biodegradable, have garnered significant attention in tissue engineering due to their potential for creating adaptable scaffolds. The adaptability of these hydrogels, made from natural proteins and polysaccharides, opens up a world of possibilities. In this study, sodium alginate was used to synthesize alginate di-aldehyde (ADA) through periodate oxidation, resulting in a lower molecular weight and reduced viscosity, with different degrees of oxidation (54% and 70%). The dual-crosslinking mechanism produced an injectable in situ hydrogel. Initially, physical crosslinking occurred between ADA and borax via borax complexation, followed by chemical crosslinking with gelatin through a Schiff's base reaction, which takes place between the amino groups of gelatin and the aldehyde groups of ADA, without requiring an external crosslinking agent. The formation of Schiff's base was confirmed by Fourier-transform infrared (FT-IR) spectroscopy. At the same time, the aldehyde groups in ADA were characterized using FT-IR, proton nuclear magnetic resonance (¹H NMR), and gel permeation chromatography (GPC), which determined its molecular weight. Furthermore, borax complexation was validated through boron-11 nuclear magnetic resonance (¹¹B NMR). The hydrogel formulation containing 70% ADA, polyethylene glycol (PEG), and 9% gelatin exhibited a decreased gelation time at physiological temperature, attributed to the increased gelatin content and higher degree of oxidation. Rheological analysis mirrored these findings, showing a correlation with gelation time. The swelling capacity was also enhanced due to the increased oxidation degree of PEG and the system's elevated gelatin content and hydrophilicity. The hydrogel demonstrated an average pore size of 40-60 µm and a compressive strength of 376.80 kPa. The lower molecular weight and varied pH conditions influenced its degradation behavior. Notably, the hydrogel's syringeability was deemed sufficient for practical applications, further enhancing its potential in tissue engineering. Given these properties, the 70% ADA/gelatin/PEG hydrogel is a promising candidate and a potential game-changer for injectable, self-crosslinking applications in tissue engineering. Its potential to revolutionize the field is inspiring and should motivate further exploration.

Electrospun nanofiber-supported thin-film composite membrane by introducing graphene oxide interlayer for water vapor/N2 separation

In response to the increasing challenge of global water scarcity, the need for alternative water resources has become increasingly critical. Membrane technologies for water vapor separation have emerged as promising approaches for water recovery and reuse. In this study, a polyethersulfone electrospun nanofiber-supported thin-film composite (eTFC) membrane structure with graphene oxide (GO) interlayer, specifically designed for water vapor/N2 separation was introduced. The interlayer was fabricated by controlling the deposition of GO on the electrospun nanofiber substrate. Subsequently, the thin-film was formed through interfacial polymerization using trimesoyl chloride and piperazine as monomers. All the prepared membranes were characterized using analytical techniques. Their water vapor separation performance was evaluated under different water activity conditions and compared to commercial membrane with similar average pore size. The optimized Gi-eTFC (with a GO interlayer of 0.4 mg) exhibited enhanced hydrophilicity, superior water vapor permeance of 3817 GPU, and a relatively high water vapor/N2 selectivity of 115, under conditions of 80 % relative humidity, 1 bar pressure, and a temperature of 30 °C. Gi-eTFC membranes with an optimized GO interlayer showed uniform and successful polyamide active-layer formation, confirming that the introduction of the GO interlayer and the use of nanofibers had a synergistic effect on improving water vapor separation performance.

Preparation and Characterization of Ni-Mn-Ga-Cu Shape Memory Alloy with Micron-Scale Pores

Porous Ni-Mn-Ga shape memory alloys (SMAs) were prepared by powder metallurgy using NaCl as a pore-forming agent with an average pore size of 20–30 μm. The microstructure, phase transformation, superelasticity, and elastocaloric properties of the porous alloys were investigated. The prepared porous alloy had a uniform pore distribution and interconnected microchannels were formed. Cu doping can effectively improve the toughness of a porous alloy, thus improving the superelasticity. It was found that porous Ni-Mn-Ga-Cu SMAs have a flat stress plateau, which exhibits a maximum elongation of 5% with partially recoverable strain and a critical stress for martensite transformation as low as about 160 MPa. In addition, an adiabatic temperature change of 0.6 K was obtained for the prepared porous alloy at a strain of 1.2% at about 150 MPa. This work confirms that the introduction of porous structures into polycrystalline Ni-Mn-Ga SMAs is an effective way to reduce costs and improve performance, and provides opportunities for engineering applications.

Investigation on the microstructure and compressive behavior of open-cell copper- Al2O3 composite foams

The objective of this study is to evaluate the mechanical behavior and energy absorption characteristics of open-cell copper- Al2O3 composite foams fabricated using polyurethane foam with an average pore size of 1.2 mm and a combination of electroless and electrodeposition methods. During electroplating process, the composite foams were fabricated with varying amounts of Al2O3 particles (0.1, 0.6, 0.8, and 1 g/l) in electrolyte solution. To assess mechanical properties of the fabricated foams, uniaxial compression test was conducted to determine the maximum compressive strength, energy absorption density, efficiency, and specific energy absorption. The content of Al2O3 in the fabricated composite foams was evaluated using energy dispersive X-ray (EDX) analysis, and the microstructure was examined using scanning electron microscopy (SEM). The results indicate that the incorporation of Al2O3 particles significantly improves the mechanical properties of the copper-Al2O3 composite foam. Specifically, in the composite foam with 9.34 vol% of Al2O3 particles, the maximum compressive strength, total energy absorption, specific energy absorption, and energy absorption efficiency reach 1.03 MPa, 6.48 MJ m−3, 1.9 J g−1, and 75%, respectively. This amount of alumina particles enhances the maximum compressive strength and total energy absorption of open-cell copper foam by approximately 30% and 100%, respectively. However, the mentioned parameters slightly decreased with an increasing amount of Al2O3 particles up to 16.32 vol%. These significant improvements in the mechanical properties of these foams make them well-suited for high-strength applications.

Efficient sealing of cemented sheath: An oil-responsive self-healing latex with toughness enhancement for cement composites

The integrity of the cemented sheath is important to the safe exploration of oil and gas resources. Sealing failure of cement sheath will result in formation fluid channeling and pressure carryover in the annulus. The both toughening and oil-responsive self-healing latex (TOS) was prepared to achieve efficient sealing of cemented sheath, and prolong its service life. The structure and oil swelling behavior of TOS, its toughening and self-healing effects on hardened cement paste (HCP) were analyzed by comprehensive characterizations. Results demonstrated that TOS possessed excellent stability and an oil swelling rate of 1235 %. Cement specimens by curing 28d containing 8 % TOS exhibited a 27.8 % increase in flexural strength, a 48.7 % reduction in elasticity modulus and a 33.8 % reduction in brittleness coefficient. The addition of TOS can effectively improve the toughness of cement. The average pore size of specimens containing 8 % TOS admixture decreased to 9.17 nm. This indicates that TOS enhanced the structural density of cement materials. The crack about 103μm in the cracking specimens with 8 % TOS was almost healed, and the corresponding permeability was reduced 99.1 % after curing in oil. Adsorption and film formation of TOS can resist the cracking of cement sheath, and the oil swelling expansion of film in cement matrix can repair the cracked structure.

Effect of Triton X-100 surfactant concentration on the wettability of polyethylene-based separators used in supercapacitors

Polyethylene-based separators are generally unsuitable for aqueous supercapacitors due to their poor wettability with the electrolyte, which impedes ion transport. However, incorporating Triton X-100 (2-[4-(2,4,4-trimethylpentan-2-yl)phenoxy]ethanol) into the aqueous sulfuric acid (H2SO4) electrolyte improves the wettability of polyethylene and facilitates ionic movement through its pores. In this study, Triton X-100 was added to 1.0 M H2SO4 at various concentrations (0.122%–1.210% V/V) to evaluate its impact on supercapacitor performance. Supercapacitors were assembled using activated carbon-filled carbon cloth electrodes, each of the above electrolytes and polyethylene sheet separators. Scanning electron microscopy revealed that the carbon cloth exhibited a uniform fiber distribution and high surface area for activated carbon integration. The polyethylene separator displayed a porous structure with an average pore size of 165 ± 35 nm. Triton X-100 significantly reduced the water contact angle from 101.5° (without surfactant) to 30.2° (with 1.21% V/V Triton X-100), enhancing polyethylene’s wettability. This change from hydrophobic to hydrophilic characteristics enabled the formation of an electrical double layer at the separator/electrolyte interface, improving ionic transport. However, higher Triton X-100 concentrations increased the electrolyte's viscosity, which impeded ion movement. The highest specific capacitance of 55.3 F/g (at a scan rate of 0.005 V s−1) was achieved with 0.488% V/V Triton X-100. The specific capacitance varied with surfactant concentration in a complex manner, influenced by micelle formation and precipitation. These findings were corroborated by cyclic voltammetry and AC impedance spectroscopy.

S-Cu Doubly Doped NiFe LDH@Diatomite with Adjustable Surface Characteristics for the Efficient Removal of Tetracycline.

Overuse of antibiotics can lead to increased bacterial resistance; therefore, there is a need to develop efficient nanomaterials for removing antibiotics from water. NiFe bimetallic hydroxide nanosheets doped with S-Cu were prepared on diatomite (S-CuNiFe LDH@diatomite) by using a two-step hydrothermal method. The surface of CuNiFe LDH@DE has a layered structure with an increased specific surface area and pore volume. The average pore size of S-CuNiFe LDH@De increases from 13.3 to 24.7 nm, and a more stereoscopic channel structure is obtained. Tetracycline removal experiments were performed on CuNiFe LDH@De and S-CuNiFe LDH@De. It was found that CuNiFe LDH@De had excellent photocatalytic performance and S-CuNiFe LDH@De had excellent adsorption performance. After CuNiFe LDH@De had been in contact with tetracycline (TC) for 2 h, the TC removal rate reached 95.6%. After S-CuNiFe LDH@De had been in contact with TC for 1 h, the adsorption capacity of TC was 145.5 mg/g. The pseudo-first-order kinetics and Sips isotherm model can be used to describe the adsorption process more accurately. The response surface method was used to optimize the adsorption conditions. According to the optimized conditions, a better adsorption performance of 166.9 mg/g was obtained. The two prepared materials showed good performance in the removal of tetracycline. This study provides a way to synthesize low-cost adsorbents and photocatalysts, which has value in the treatment of TC wastewater.

Structure-property relationships of polydisperse open-cell foams: Application to melamine foams

The melamine foam presents a unique microstructure characterized by an interconnected network of solid struts, which form the edges and faces of high porosity open cells. This study investigates the influence of pore size distribution on acoustic properties for three commercially available melamine foams. Based on the measured transport parameters, a top-down approach is employed to determine the equivalent Kelvin-cell size corresponding to each transport parameter. The differences found in these equivalent pore sizes indicate that the mono-size model is not suitable for these materials, a difference from which a quantitative estimate of the level of polydispersity can be deduced (using macro-scale information). The polydispersity was confirmed from experimental evidence at micro-scale from the analysis of SEM images. Moreover, the measurements collected at micro-scale (average pore size and its standard deviation) can be used as input data to determine the transport and sound absorbing behavior of melamine foam samples from structure-property relationships available for open cell microstructures. This work provides evidence that the polydispersity of melamine foams should be taken into account to obtain an accurate and consistent picture of microstructure and transport properties of such open cell high porosity foams.

Development and characterization of an asymmetrical flat microfiltration membrane based on natural phengite clay: Application as a pretreatment for raw seawater reverse osmosis desalination

The work focuses on developing a new asymmetric flat microfiltration membrane using an inexpensive geological material, natural Moroccan phengite clay. The optimal porous ceramic support was prepared by applying the paste casting method and sintering at a low temperature of 1050 °C for 2 h. Secondly, the microfiltration layer was developed by the spin coating method. The layer was then dried and sintered at 850 °C/2h. SEM analysis revealed that the morphological structure of the layer is homogeneous and free from cracks. Furthermore, the microfiltration layer has an average pore size of 1.23 μm, a thickness ranging from 30.3 μm to 31.3 μm, a water permeability of 258.1 L/h.m2.bar, and good chemical stability against corrosion. The performance of the manufactured membrane was evaluated by filtering raw seawater (RSW1 and RSW2) as a potential application for seawater pretreatment before desalination by reverse osmosis. The prepared membrane significantly reduced turbidity concentrations by 98.7 % for RSW1 and 96.8 % for RSW2. The fouling and antifouling mechanisms were also examined. Finally, the preparation cost of the phengite membrane was estimated to be 125 $/m2.

Effect of pH, acid catalyst, and aging time on pore characteristics of dried silica xerogel

ABSTRACT This study investigates the impact of pH and ageing time on silica xerogel pore characteristics prepared via the sol-gel method. Using tetraethyl orthosilicate (TEOS) and HCl as a precursor and acid catalyst, respectively, tailored pore size distributions in the meso- and macroporous range were achieved. Field emission scanning electron microscopy (FESEM) revealed interconnected porous structures, with pore size increasing linearly with ageing time. pH variation yielded average pore sizes ranging from ~ 31 nm (mesoporous) to ~ 59 nm (macroporous). Higher acid catalyst concentration accelerated gelation, resulting in smaller pores. Elemental analysis confirmed silicon and oxygen as primary constituents, while X-ray diffraction (XRD) confirmed amorphous nature. Sol-gel synthesis provides versatile control over microstructure and properties, enabling customisation for applications such as liquid filters, batteries, sensors, and bio-scaffolds. It offers a cost-effective, direct synthesis of high-purity multi-component materials, emphasising its potential for functional material development.

Green self-templated synthesis of P-doped mesoporous carbon from dual sodium salts with improved average pore size for capacitive deionization

Mesoporous carbon materials hold significant potential in capacitive deionization (CDI) technology owing to expansive accessible surface area, more adaptable pore structure, excellent conductivity properties and effective surface modification and functionalization. While templating is a common method for synthesizing mesoporous carbons, the commonly used hard and soft templating approaches among them suffer from the challenges of expensive precursors and templating agents, complex procedures, secondary contaminants and difficulties in template removal. In contrast, the self-templating method not only circumvents the traditional template removal or combustion steps but also eliminates the use of organic solvents and hazardous chemicals, thus minimizing environmental impact. In this paper, we have successfully synthesized phosphorus-doped mesoporous carbon with a large average pore size (paver) using a green and convenient self-templating method employing dual sodium salts of sodium alginate (SA) and sodium phytate (SP). Compared to single SA (6.76 nm) or SP (3.74 nm) self-templated carbonization, the average pore size of carbon materials obtained from dual self-templated carbonization with a proportional mixture (12.97 nm) is significantly improved. The larger average pore size provides a greater surface area for electrode-electrolyte interactions, allowing for easier access and faster diffusion of ions into the pores, thereby enhancing the electrochemical and capacitive deionization properties of the material. The resulting material demonstrates promising electrochemical and desalination performance as evidenced by possessing a specific capacitance of 175.8 A/g and an adsorption capacity of 19.65 mg/g, underlining its potential for application in capacitive deionization utilizing mesoporous carbon materials with large average pore size.

Influence of different composite curing agents on the rapid curing characteristics and mechanical performance of epoxy resins

To address the need for rapid in situ plugging and repair of hydraulic machinery and chemical pipelines and to resolve the issue that a single curing agent cannot simultaneously achieve rapid curing and excellent mechanical properties in epoxy resin systems, this study explores the use of composite curing agents. In particular, effective formulations are designed for mixing fast and slow curing agents, studying their effects on the curing behavior, curing quality, and mechanical properties of epoxy resins and elucidating their influence mechanisms. The results indicate that three resin systems meet the requirements for rapid curing (curing time within 30 min): 4A6B/EP, 2A8B/EP, and 0A10B/EP. Among them, 4A6B/EP exhibits the best curing quality and mechanical properties. In particular, 4A6B/EP demonstrates the lowest values of curing shrinkage rate, internal curing stress, average pore size, porosity, and cumulative pore volume. Its low internal stress and low defects reduce the stress concentration, while more efficient deflection and branching of internal cracks enhance its deformation resistance. Consequently, 4A6B/EP shows the highest microhardness, fracture toughness, tensile strength, Young’s modulus, and elongation after fracture. Based on the comprehensive evaluation of rapid curing characteristics and mechanical properties, the 4A6B/EP system offers the best overall performance. Therefore, it is recommended as the preferred resin system for rapid plugging and repair of composite materials, providing a theoretical basis and technical support for boosting the application of epoxy resin composite materials in high-tech fields.