Surface Micropore Research Articles

Removal of bisphenol A (BPA) from aqueous solution by potassium carbonate modified wetland plant biochars

Bisphenol A (BPA) is a known endocrine disruptor that is acutely toxic to the living organisms. In this study, the wetland plants Phragmites australis and Typha orientalis were subjected to carbonize at 500℃ for different durations (4, 5, and 6h) and varying mass ratios of wetland plants to potassium carbonate (1:2, 1:1, and 2:1). The prepared modified biochars were used to treat BPA in solution to explore the effect of contact time and initial concentration of BPA on adsorption performance. Both adsorption kinetic models and isotherm models were also studied. The results demonstrated a gradual increase in the adsorption capacity of Phragmites australis and Typha orientalis biochars for BPA with prolonged contact time. Furthermore, an enhancement in the adsorption capacity was observed with increasing initial BPA concentration. The modified biochars significantly enhanced BPA removal and adsorption capacities for BPA compared to the unmodified biochars. L55C (Phragmites australis carbonized at 500℃ for 5h with a mass ratio of 2:1) and X54C (Phragmites australis carbonized at 500 ℃ for 4h with a mass ratio of 2:1) exhibited the largest total surface areas, total pore volumes, microporous surface areas and microporous volumes, and achieved maximum adsorption capacities of 8.547 and 8.117mg/g, respectively. The adsorption processes were fitted with pseudo-second-order adsorption kinetic models and Langmuir models. The adsorption processes were monolayer chemical adsorption.

Magnetic solid-phase extraction of trace elements in water and fish using greenly synthesized MnFe2O4 @ cabbage hydrochar/chitosan ternary composite

A new analytical method for determining lead, cadmium, and copper in water and fish was established employing a novel synthesized magnetic eco-friendly ternary nano-composite adsorbent of manganese ferrite@cabbage hydrochar/chitosan (MnFe2O4@CBH/CTS). Cabbage leaves were employed as a green fuel, acting as a reducing and capping agent in the green manufacture of manganese-ferrite nanoparticles, and then hydrothermally carbonized to form hydrochar. The novel material underwent FT-IR, XRD, SEM, EDX, and BET investigation, revealing a micro-porous surface. The magnetic solid-phase extraction (MSPE) technique was used to enrich the samples and separate the matrix for GFAAS analysis. The impact of adsorption factors such as pH, extraction duration, metal ion concentration, and interference from coexisting ions were examined. Based on a preconcentration factor of 50, the method demonstrated LOD (3σ/m) ranging from 6 to 18 ng L−1, linearity (ng L−1) from 48 to 450 (Pb), 20–180 (Cd) and 59–300 (Cu), and precision (RSD, n=3) of 1.8–3.9 % (1.0 μg L−1) and 3.0–4.6 % (10 μg L−1). The approach was effectively applied to the analysis of tested elements in water and marine fish samples, with spiked sample recoveries above 95 % and an RSD of less than 5.4 %.

Flow boiling heat transfer in multi-stage enhanced open microchannels with micro/nano structures

In the realm of flow boiling research, open microchannels heat sink is garnering more attention due to its potential in enhancing heat transfer and mitigating flow instability. Nevertheless, growing heat dissipation needs necessitate further enhancement of the heat removing capability of flow boiling within open microchannels. In this paper, experimental research on flow boiling in open microchannels utilized a new environmentally friendly refrigerant SF-33 and presented a novel heat transfer enhancement strategy, specifically, a multi-region enhancement strategy for diverse flow pattern stages. A copper heat sink with 25 open microchannels was fabricated, and a layer of copper powder particles was sintered on the channel bottom to create a microporous structured surface in about 1/3 of the inlet region. Several layers of copper wire mesh with micropores were sintered in about 1/3 of the outlet region, and the nanostructures were grown on the wire mesh by chemical treatment, resulting in a micro-nanocomposite structure. The final product formed the multi-stage enhanced open microchannels (MSEOM). The heat transfer performance and pressure drop of SF-33 saturated flow boiling in MSEOM under different operating conditions were determined, and the transitions of flow patterns were visualized to analyze the mechanism of two-phase heat transfer. The study demonstrated that despite SF-33 having a low latent heat of vaporization, its flow boiling heat transfer coefficient in MSEOM was high. This was attributed to the enhanced effect of multi-region surface modifications on heat transfer. Additionally, a vapor plug breakup-dispersed bubble flow pattern was observed for the first time, which resulted from the combined influence of the low surface tension property of SF-33 and the boosted nucleate boiling triggered by the micro-nanostructures in the outlet region.

Adsorbent Properties of Porous Boron Nitride and Activated Carbon: A Comparative Study.

Porous boron nitrides possess beneficial properties such as high thermal and chemical stability which are critical for applications in adsorption processes. In order to assess possible fields of applications, trace-level adsorption isotherms of different hydrocarbons on two synthesized porous boron nitrides and two commercial activated carbons are compared. By normalizing the adsorptive loadings on the micropore surface area, superior adsorption performances of the BN materials on polar and aromatic adsorptives with up to 50% higher loadings compared to the activated carbons can be shown. Nonpolar adsorptives, on the other hand, feature higher specific loadings on the activated carbon. Consequently, the size of the micropore surface appears to be decisive for nonpolar adsorptives, while the higher polarity of the boron nitrides is the dominant influencing factor for the adsorption of polar and aromatic components. For an energetic study of the adsorbents, calorimetric experiments were performed to identify and discuss adsorbent-adsorptive interactions. While the initial heat of adsorption of the nonpolar n-hexane is lower on the boron nitride than on the activated carbon due to a less favorable spatial arrangement, toluene shows comparable values on both adsorbent classes and the polar acetone shows higher values on the polar boron nitride. Considering technical applications in adsorption technology, the thermal stability of the boron nitrides is investigated using spontaneous ignition temperatures and points of initial oxidation. Here, the porous boron nitrides with oxidation temperatures above 900 °C show about 400 °C higher values and thus a significantly higher thermal stability.

Evaluation of the effect of ultrasound-assisted hot air drying on the drying characteristics and physicochemical properties of cherries based on the entropy-weighted TOPSIS method.

To address the challenges associated with prolonged traditional hot air drying (HAD) times and significant nutrient loss in cherries, this study employs ultrasound-assisted hot air drying (USA-HAD) technology. The study investigates the impacts of various ultrasound (US) frequencies, US powers, and hot air temperatures on the drying kinetics, physicochemical properties, texture attributes, and microstructure of cherries during drying. Cherry physicochemical quality serves as the evaluation criterion, with the entropy-weighted TOPSIS method used to identify the optimal drying parameters. The findings indicate that USA-HAD accelerates the drying process, reduces drying time, and enhances drying efficiency. In comparison to natural drying, USA-HAD significantly preserves polysaccharides, total phenolic content, total flavonoid content, and organic acids in cherries, while boosting antioxidant activity. Concurrently, it reduces color intensity, as well as the hardness, chewiness, and gumminess of dried cherry products. Microstructural observations under different drying methods reveal an increase in surface micropores and relatively intact tissue structure. Under conditions of 55°C, 48W, and 28kHz, cherries exhibit superior overall quality based on the TOPSIS relative closeness degree. This study offers practical insights for optimizing post-harvest processing of cherries. PRACTICAL APPLICATION: In this rapidly evolving era, the application of combination drying technology is clearly on the rise. The USA-HAD treated cherries had better nutritional and bioactive than HAD. The conclusions obtained indicate that the USA-HAD technology has more potential for development.

Remarkable improvement in the NOx storage ability of Pd/SSZ-13 zeolite PNA via a facile pretreatment strategy

A facile strategy was employed to pretreat Pd/SSZ-13 zeolite obtained via the initial-impregnated method under a microwave field, aiming to greatly enhancing the NOx storage-release ability. By investigating the effect of microwave treatment parameters (power, atmosphere and time) on the improvement of PNA performance, the optimal conditions were determined (175 W, 10 % O2/N2, 15 min). Under these conditions, the Pd/SSZ-13 exhibited an enhanced NOx adsorption and desorption amount to 2.60 and 2.38 times, respectively, compared to the untreated sample after three cycles of NO-TPD. Deeper insights into the variations in Pd/SSZ-13 properties induced by the microwave radiation were clarified through a series of characterizations. The micropore surface area of Pd/SSZ-13 zeolite activated by microwave increased by 3.91 %, and the micropore volume also improved by 3.85 %, which might facilitate the adhesion of more active Pd species to the materials surface, and aid in the dispersion of PdOx clusters into the zeolite channels. After microwave activation, the average particle size of Pd decreased from 10.09 nm to 7.08 nm. Particularly, the content of Pd(II) species such as Pd2+, [Pd(OH)]+ and PdO as active NOx adsorption sites enhanced from 66.68 % to 68.93 %. Additionally, the microwave treatment not only increased the number of Lewis and Brønsted acid sites, but also strengthened the interaction between NOx molecules and the zeolite skeleton. The above reasons collectively promoted the NOx storage-release properties of Pd/SSZ-13 zeolite, showing that the microwave pretreatment is a highly efficient strategy for improving the performance of PNA materials.

Supercritical Methane Adsorption Characteristics and Pore Structure Characteristics of Deep Middle Rank Coal

Abstract In order to accurately analyze the adsorption characteristics, pore structure, and fractal law of deep middle rank coal, high-pressure isothermal adsorption tests based on magnetic levitation high-pressure thermobalance and pore structure tests based on mercury intrusion method were carried out on coal samples collected from typical kilometer level deep wells. The fractal law of sponge model was studied. The results showed that: a. The weight method adsorption test showed “excess adsorption” phenomenon with the increase of equilibrium pressure, and the modified Gibbs surface excess adsorption theory was in line with the Langmuir adsorption model; b. The distribution of macropore volume in deep middle rank coal accounts for a dominant proportion of 57.44% to 62.47%, and the proportion of microporous specific surface area reaches 72.96% to 74.27%, indicating that microporous adsorption capacity is the strongest; c. The pore structure parameters and adsorption constants exhibit strong nonlinear characteristics.

Optimized Microporous Surfaces Increase Bond durability of NPJ-printed zirconia

Optimized Microporous Surfaces Increase Bond durability of NPJ-printed zirconia

Low Ru doping induced interface and defects engineering in 2D square micro-mesoporous CoNiRuOx nanosieves for advanced oxygen evolution electrocatalysis

Efficient oxygen evolution reaction (OER) catalysts require the reasonable integration of geometric architecture, defects construction and interfacial electronic structure, which is difficult to combine multiple advantages into one low-cost catalysts. Herein, we designed a novel low Ru doping 2D square CoNiRuOx nanosieves (NSs) with abundant surface micropore and mesopore structure, rich oxygen defects and heterophase interfaces. Owing to the Ru incorporation, the electrons in Ni2+ could partially spontaneously transfer to the Ru4+ species by the bridge O2− with π donation effect according to the proposed “Ni-O-Co-O-Ru-O-Ni” electron interaction model. Benefitting from the porous surface with rich mass transfer channel, increased oxygen defects concentration, well-optimized electron redistribution, the CoNiRuOx nanosieves possessed a low overpotential of 261 mV to reach the current density of 10 mA cm−2, which is better than that of counterpart CoNiOx NSs and commercial RuO2 catalysts. The CoNiRuOx NSs also possessed the favorable durability with 50 h. Moreover, the CoNiRuOx//Pt/C electrode couple exhibited enhanced overall water splitting performance. This work provides offers insightful significance to design 2D micro-mesoporous materials for the robust electrocatalysis processes related to energy conversion technologies.

The effect of thermal aging on microhardness and SEM/EDS for characterisation bioactive filling materials

BackgroundThe aim of this study is to evaluate the surface microhardness, surface chemical composition of bioactive restorative materials pre- and post- thermal aging.MethodA total of 200 disc-shaped samples were prepared by using the materials: Cention N, ACTIVA BioActive Restorative, Equia Forte HT Fil, Glass Fill glass carbomer cement (GCP), and Fuji II LC. Vickers microhardness test were used to measure surface hardness. Scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM/EDS) was used to determine the characterization of the microstructures and elemental analysis of the materials. These measurements were repeated after thermal aging. One-Way ANOVA test, Bonferroni test and the Games-Howell test was used for data analysis. The significance level was accepted as 0.05.ResultsCention N had the highest vickers microhardness value before thermal cycle. The highest fluoride ion ratio among the materials before thermal aging was detected in the Equia Forte HT Fil and Fuji II LC groups. While a decrease in fluorideF ion was detected in all groups except the Cention N group after thermal aging. It is observed that ACTIVA BioActive Restorative has a more microporous and rougher surface in the scanning electron microscopy image after the thermal cycle than in the image before the thermal cycle.ConclusionsThe chemical properties of the materials and the properties of the filler particles may be related to the differences in the mechanical properties, surface characterizations and ion releases of the materials Thermal aging affected the microhardness, surface characteristics and elemental mass ratios of the studied materials. Alkasite bioactive materials are more similar to composite restorative materials and show better mechanical properties than other materials, but do not have the same effect on fluoride release.Clinical relevanceMost of the bioactive materials showed a decrease in the fluoride ion ratio after thermal aging, while no difference was found in the ion exchange of alkasite materials. Material selection should be made more carefully in caries-active individuals whose fluoride release is clinically important.

Hydrophobic ZIF-8 nanoparticles loaded on chitosan for improved methanol adsorption from fermented wine.

Metal-organic frameworks (MOFs) have great potential for the adsorption of minor molecular alcohols in the vapor phase. However, the drawbacks of powdered MOFs, including low recyclability and problematic separation, limit their application in fermented wine. Chitosan (CS) is a low-cost, eco-friendly, moldable matrix used in the food industry. In this study, a novel CS@ZIF-8 adsorbent with excellent microporous surface area was successfully synthesized by incorporating hydrophobic ZIF-8 into CS. The results showed that CS@ZIF-8 beads had a high adsorption affinity for methanol at a Zn2+/2-methylimidazole molar ratio of 1:5. The adsorption mechanism of methanol on CS@ZIF-8 beads was systematically studied by X-ray photoelectron spectroscopy, isotherms, and kinetics. The Langmuir model calculated the maximum adsorption of methanol to 56.8mg/g. Adsorption kinetics are consistent with pseudo-second-order models. Furthermore, CS@ZIF-8 beads presented excellent recyclability for removing methanol for five consecutive cycles. It could treat 60 bed volumes of Chinese yellow wine in column filtration experiments to make the concentration below 50mg/L. In summary, the highly efficient CS@ZIF-8 adsorbent has great potential for methanol adsorption from fermented wines. PRACTICAL APPLICATION: Methanol will exhibit adverse symptoms such as weakness and headaches after it is ingested. Therefore, methanol control is an important safety factor in the production of fermented wine. The adsorption method is recognized as a widely used technique due to its high efficiency and selectivity. The CS@ZIF-8 adsorbent synthesized in this paper provides a new idea for methanol removal.

Evaluation of Zeolite Composites by IR and NMR Spectroscopy.

In this study, we assessed the quantity, strength, and acidity of zeolite composites comprising Silicalite-1 grown on ZSM-5 crystals using a combination of infrared (IR) and solid-state nuclear magnetic resonance (NMR) spectroscopy. The composites were created through the direct growth of Silicalite-1 crystals on ZSM-5 (P_ZSM-5), either with or without the organic structure-directing agent (OSDA) introduced into the ZSM-5 channels (samples: H_ZSM-5_Sil1 and TPA_ZSM-5_Sil1). The results revealed that Silicalite-1 grew differently when the ZSM-5 core was in the H+ form (empty pores) compared to when the OSDA was still present in the sample. This distinction was evident in the textural properties, with a decrease in the micropore surface area and an increase in the external surface area in the H_ZSM-5_Sil1 compared to the parent sample. The TPA_ZSM-5_Sil1 composite exhibited characteristics similar to the parent zeolite. These findings were further supported by 29Si NMR, which revealed a comparable local order for the parent (P_ZSM-5) and TPA_ZSM-5_Sil1 samples, along with a broadening of the Q4 peak for the H_ZSM-5_Sil1 composite. Additionally, the acid sites were preserved in the TPA_ZSM-5_Sil1 composite, while in the H+-form core, the concentration of Brønsted acid sites significantly decreased. This reduction in isolated Brønsted acid sites was further corroborated by 1H NMR.

Activated carbons from Brazilian lignocellulosic residues from baru and jurubeba as adsorbents for removal of diethyl phthalate in aqueous phase

New insights were achieved for the removal of plasticizer in the aqueous phase, through adsorption by H3PO4 and H2SO4 activated carbons. The preparation was made from Brazilian lignocellulosic residues from of the baru shell (Dipteryx alata) and the jurubeba fruit (Solanum paniculatum). Such residues were characterized by biochemical, elemental, thermogravimetric, Fourier Transform Infrared analyses. Subsequently, the influence of the biomass/acidity ratio (1/2; 1/3) was analyzed by applying adsorption kinetics for a diethyl phthalate concentration of 0.2 g L‐1, isotherms, and modeling. Chemical activation was carried out at 80 ºC 30 min‐1, drying at 110 ºC 15 h‐1 and carbonization under N2 flow at 800 ºC 60 min‐1 at a heating rate of 20 ºC min‐1. Precursors and ACs were characterized by nitrogen isotherm at 77 K, TGA-DTG, FT-IR, pHPZC. The reaction mechanisms, applicability of ACs were analyzed. ACs' yields varied: 31.7–50.4% (baru); 30–41.7% (jurubeba). The ACs exhibited a range of textural properties from: specific surface area (SBET): 2–269 m² g‐1, micropore volume (W0): 0.10–0.56 cm3 g‐1, micropore width (L0): 9.3–17.6 Å. Results revealed high thermal resistance, amorphous structure, mesoporous surfaces for baru ACs, microporous surfaces for jurubeba ACs, both predominantly acidic: pHPZC 1.8–3.9. This acidity facilitated non-electrostatic interactions during the adsorption.

Assessment of process parameters on modified 316L SS surfaces prepared via hybrid powders mixed EDM

This study aims to assess the influence of hybrid powders (hydroxyapatite, manganese, copper, and carbon nanotube) mixed electric discharge machining (EDM) and coating process on 316L stainless steel (SS). An efficiently machined, hydrophilic, thin, and microporous surface is produced using variable discharge energies and powders weighted percentage suspended in the dielectric medium. The research outcome indicates that the hybrid powders mixed-EDM process synthesised a coating that substitutes the base elements with foreign elements of calcium (Ca), phosphorous (P), copper (Cu), carbon (C), oxygen (O), and manganese (Mn). The surface wettability response of the coating displays a hydrophilic nature with a contact angle of 51.5° and surface energy of 52.9 mJ m−2. The coated surface exhibited a roughness value of 3.201 μm, which is expected to promote osseointegration, and the material removal rate has been enhanced to an optimal value of 100.32 mg/min. The Taguchi design demonstrated that the powder mixing ratio, current intensity, and spark time are the most influential factors in the hybrid powders mixed EDM process. This study determines a novel multiple additives-assisted EDM method to synthesise a coating on 316L SS with potential benefits for biomedical applications.

Exploring the room temperature chemiresistive LPG and humidity sensing properties of MWCNT/TiO2 nanocomposite with DFT interpretations

A nano-sized multi-walled carbon nanotube/titanium dioxide (MWCNT/TiO2) composite gas sensing material was synthesized using the chemical vapor deposition method and extensively characterized through advanced techniques. Scanning electron microscopy (SEM) revealed a microporous surface featuring a cross-linked nanotube structure in the thin film. The bandgap, determined from absorption spectra, was calculated to be 3.89 eV. Electrical resistance variations in response to liquefied petroleum gas (LPG) concentrations (0.5–2 vol%) were systematically recorded over time, with the maximum %sensor response of 423.2 at 2 vol%, indicating high sensitivity. The sensor response towards humidity was found as 1.05 MΩ/%RH at room temperature. The limit of detection (LOD) for LPG by using MWCNT/TiO2 at room temperature was found to be 0.063 vol%. Ab initio density functional theory (DFT) calculations provided insights into the adsorption mechanisms of LPG and H2O on the CNT/TiO2 surface, assessing changes in ionization potential, HOMO-LUMO gap, and electronegativity upon interaction with hydroxyl and CnH2n+2 groups. This comprehensive approach highlights the development of a robust, cost-effective, and technologically advanced sensor for LPG and humidity detection.

Wetting Dynamics Behavior of In Situ Generated Droplet on Micropore Surfaces

The pinning dynamic of oil droplet on micropore surface has a significant impact on the stability of the oil film. Herein, the numerical model of the oil droplet generated in situ at the orifices is established. The influence of pore parameters and the inlet pressure on the movement of the three‐phase contact line are explored. The transformation mechanism between pinning and spreading of the droplet is revealed. The result shows that due to the competition between the surface tension and the driving force, the flow field parameters at the pinning point become unstable. Until the three‐phase contact line is unpinned, the droplet spreads on the micropore surface. With the reduce of the contact angle or the increase of the diameter of the pore, the pinning time of the droplet is shortened, and the droplets spread faster on the micropore surface. As the inlet pressure increases, the droplets grow faster at the orifice and spread from the orifice until the apparent contact angle reaches its maximum forward angle. The spread promotes the regeneration of the lubricating film, which is conducive to improving the stability of the oil film on micropore surface.

Ti3+ self-doped TiO2 nanoparticles immobilized on self-pillared pentasil zeolite nanosheets: An efficient visible-light-driven degradation photocatalyst

Ti3+ defective TiO2 nanoparticles (TiO2-NPs) were synthesized through slow hydrolyzation of tetrabutyl titanate and low-temperature annealing, followed by loading on self-pillared pentasil (SPP) zeolite nanosheets to construct a TiO2/zeolite hybrid composite by solid-state dispersion. The obtained TiO2-NPs/SPP composite exhibited a distinct red-shift in the UV–vis absorption spectrum and a significantly reduced band gap due to the introduced Ti3+ defects and the consequent oxygen vacancies (VO), leading to an enhanced visible-light responsivity. The diverse porosity and house-of-cards nanosheet morphology of the SPP support not only promoted the efficient loading and stable immobilization of TiO2-NPs nanoparicles through micropore migration and surface adhesion but also endowed the adsorbability to the TiO2-NPs/SPP composite. The adsorptive photodegradation of methylene blue (MB) was used to evaluated the photocatalytic performance of TiO2-NPs/SPP, and a 95.6 % degradation rate of MB was observed after 3 h illumination with visible-light. The adsorptive effect strongly promoted the accessibility of MB molecules to the active TiO2 species, leading to a remarkable enhancement in degradation efficiency. Moreover, a superior recyclability embodied in the retention of 96.4 % photocatalytic activity after three regeneration cycles indicated the TiO2-NPs/SPP composite to be practical for water pollutant degradation.

Facile and binder free nano-architecturing of anode with biocompatible g-C3N4-PPy for bacterial community enrichment and green energy generation in microbial fuel cells

The adoption of microbial fuel cells (MFCs) as waste-to-power solution for green energy generation while treating wastewater has attracted considerable attention. However, their wide-scale expansion requires further improvements, particularly by anode modifications which necessitates the development of anodes with large surface area, high electrical conductivity, and biocompatibility. Thus, herein, we present a novel and facile approach for the modification of carbon felt (CF) with graphitic carbon nitride (g-C3N4) and polypyrrole (PPy) to create a highly biocompatible anode following a binder-free route. Increased surface area with microporous rough surface of modified electrodes was confirmed through scanning electron microscopy (SEM) and atomic force microscopy (AFM). The g-C3N4@PPy-CF anode exhibited minimal water contact angle of 0.9°, in contrast to g-C3N4-CF (53.5°) and pristine CF (123.8°), indicating enhanced hydrophilicity essential for biofilm formation. The synergy between g-C3N4 and polypyrrole results in remarkable 80.7% higher power output (205.8 ± 7.36 mW/m2) and 47% higher current response (8.24 mA) as compared to pristine-CF. Efficient extracellular electron transport (EET) was enacted through better interfacial contact between electrode and electroactive bacteria (EAB), as evidenced by the minimal charge transfer resistance in g-C3N4@PPy-CF (4.21 Ω) and g-C3N4-CF (6.47 Ω), while 68% higher resistance (7.06 Ω) with pristine-CF. Microbial characterization of biofilms showed enrichment of electroactive bacteria, mainly the Proteobacteria phylum comprised 79–82% of total microbial community in modified electrodes while it was 74% in pristine CF. Acinetobacter (25.9%) and Desulfuromonas (17.9%) emerges as major electroactive genera on g-C3N4@PPy-CF contributing to its excellent bio-electrogenic performance. Thus, the low-cost, binder-free and facilely fabricated novel anode with stable electrogenic efficiency provides solution to longstanding challenge of suboptimal anode performance and opens new avenues for scale-up of sustainable energy generation from wastewater using MFCs.

Highly microporous activated carbons synthesized from sacrificial templating of melamine for CH4 and H2 storages and CH4/H2 adsorptive separation

Achieving carbon neutrality necessitates advancements in adsorbent-based gas storage technologies, particularly for maximizing the utilization of natural gas (CH4) and hydrogen (H2) as sustainable energy sources. Activated carbons, characterized by their high surface area, stability, and cost-effectiveness, emerge as promising candidates for CH4 and H2 storage applications. Here, we report highly microporous activated carbons prepared using sacrificial templating of melamine followed by Cs+ ion activation. The resulting activated carbon demonstrates exceptional microporous characteristics, boasting a significantly high micropore surface area (2311 m2/g) and micropore volume (1.070 cm3 g−1). These structural attributes translate into impressive CH4 (11.92 mmol/g at 298 K and 70 bar) and H2 (2.74 mmol/g at 298 K and 70 bar) storage capacities, underscoring its potential as a viable ambient temperature gas storage material. Furthermore, our evaluation extends to the performance of the activated carbon for adsorptive CH4/H2 separation. The activated carbon exhibits a notable CH4 working capacity (3.13 mmol/g at 298 K, 1–10 bar pressure swing) coupled with a moderate Ideal Adsorbed Solution Theory (IAST) selectivity (25). These findings highlight the suitability of the activated carbon for both CH4 and H2 storage applications, as well as the separation of H2 from CH4.

Research on micro-arc oxidation method based on passivation layer on non-valve metal low-carbon steel surface

In this study, a method for preparing micro-arc oxidation (MAO) coatings on the surface of non-valve metal low-carbon steel based on a passivation layer is proposed. Microstructure and elemental composition of the surface and cross-section were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy-dispersive spectroscopy (EDS). Micro-scratch tests, tribological tests and electrochemical corrosion tests were conducted. Compared to MAO coatings, coatings obtained by pre-passivation treatment exhibit fewer surface micropores with smaller pore sizes, and both wear resistance and corrosion resistance are enhanced. In summary, the method for preparing MAO coatings based on the passivation layer on the surface of low-carbon steel provides feasible approach to improving the drawbacks of low-carbon steel.