Surface Micropore Research Articles

Engineering the Pore Structure and Functionality of Ionic Porous Polymers for Separating Acetylene over Carbon Dioxide

AbstractPrecise engineering of organic porous polymers to realize the selective separation of structurally similar gases presents a great challenge. In this study, a new class of ionic porous polymers P(Ph3Im‐Br‐nDVB) with a high ionic density and microporous surface area are constructed through a facile copolymerization strategy, providing an efficient path to rational control over pore structure and functionality. The first example of ionic porous organic polymers is reported to address the challenge of discriminating the subtle difference of C2H2 and CO2, which have almost identical molecular sizes and similar physicochemical properties, which achieve the highest C2H2/CO2 selectivity (17.9) among porous organic polymers. These ionic porous polymers exhibit high stability and excellent dynamic breakthrough performance for binary C2H2/CO2 mixtures, indicating their practical feasibility. Modeling studies reveal that anions are the specific binding sites for preferential C2H2 capture because of Br−···HCCH interactions. This study not only demonstrates an efficient strategy to build novel ionic porous polymers integrating abundant micropores and ionic sites but also sheds some light on the development of functionalized materials for the separation of structurally similar gas molecules.

Experimental study of heat transfer in a microchannel with pin fins and sintered coatings

ABSTRACT Increasing processing capacity without modifying the size of electronic devices has made thermal management important in the electronic industry. Commercialized thermal management, such as in a conventional air cooling system, is insufficient for electronic devices with high heat flux dissipation. Pool boiling is a better method for heat transfer because it can dissipate a substantial amount of heat at low wall superheats. This study focused on heat transfer enhancement using passive approaches, including nanostructures and microporous sintered surfaces over open microchannel surfaces and microchannels with pin-fins. In the present work, seven structures were studied in pool boiling, wherein experiments elucidated the effects of microchannels, sintered, and pin fins (micropillar) on boiling heat transfer from a copper chip in a pool of degassed water. Boiling performance is ascertained via critical heat flux (CHF) and heat transfer coefficient (HTC). The best heat transfer performance showed a heat flux of 243.75W/cm2 at 15.46°C on the pin-fins chip, which was 1.9 times the heat flux of the plain chip. The highest HTC was 181.03 kW/(m2 oC) at a heat flux of 172.61 W/cm2 for the microchannel with single pin-fins. The HTC enhancement was 2.8 times greater than the plain surface. It was found experimentally that HTC and CHF improved on all modified surfaces compared to the plain copper chip baseline.

Design strategy for hierarchical structure of carbon black on microporous elastomer surface toward stretchable and compressive strain sensors

Flexible mechanical sensors capable of sensing both compressive and tensile strains with high sensitivity and linear piezoresistive response are of great significance for the development of wearable devices, flexible electronic skins, and robotics. However, it is still of challenge to develop simple 3-dimensional (3D) porous polymer/carbon nanomaterial composite strain sensors capable of sensing both tensile and compressive strains with reproducible electrical signals. Herein, we report a simple and scalable morphology-engineering strategy, i.e., selective location of carbon black (CB) in polyoxyethylene (PEO)/ethylene-α-octene random copolymer (ORC) blends via phase separation, to fabricate isotropic 3D continuous porous composite strain sensors. Such a composite consists of a continuous porous ORC matrix inlaid with preferable CB distribution on ORC surface after PEO removal, enabling distinguishable detection of both compressive and tensile strains with opposite resistance changes. Specifically, the as-fabricated strain sensors exhibit linear response with a sensitivity of 16 for 0–46% compressive strain, a detection limit of 0.3% strain with 16/16 ms response/recovery time. Besides, it has a large gauge factor for tensile strain of 0–300%, a detection limit strain of 0.06% with 16/47 ms response/recovery time, and low hysteresis degree. As such, it allows for full-range body motion monitoring and Morse code communication.

Polyaniline Hybrids with Biological Tissue, and Biological Polymers as Physiological—Electroactive Materials

A sprout/polyaniline was synthesized via the chemical oxidative polymerization of aniline in the presence of natural sprout, based on a concept of cyborg plant composite. The composite consisted of both polyaniline and plants. The chemical structure was confirmed by infrared absorption spectroscopy measurements. Optical microscopy observation revealed that polyaniline was deposited into the micro-tissue of the sprout to form the conductive polymer bio-composite. Micro-optical fiber functions for the composite were visually confirmed. Furthermore, the sprout/polyaniline based organic diode exhibited an avalanche breakdown phenomenon. Next, a fucoidan/polyaniline composite as a physiological active material/conducting polymer composite was prepared. This composite showed good film-forming ability, electrochromism, and a micro-porous surface. This paper reports the preparation of conducting polymer composites with a combination of bio-tissue and bio-substance for the creation of bio-based electrically active organized architecture.

Customized oxygen-rich biochar with ultrahigh microporosity for ideal solid phase microextraction of substituted benzenes

The synergistic effect of high microporosity and abundant heteroatoms is important for improving the performance of biochar in various fields. However, it is still challenging to create enough micropores for biochar, while simultaneously retaining the heteroatoms from biomass. A series of biochar with variable microstructures was successfully prepared by carbonization and following ball milling on lotus pedicel (LP), watermelon rind (WR), and litchi rind (LR). The pore structures and heteroatoms of biochar were characterized in detail. Notably, high microporosity could be realized by the carbonization of LR, and further ball milling resulted in a higher microporous surface area (1323.4 m2·g−1) and richer oxygen. Furthermore, the obtained biochar was fabricated as solid phase microextraction (SPME) coatings with uniform morphologies and similar thicknesses to deeply investigate the relationships between the microstructures and extraction performance. The best performance was demonstrated by the LR800BM, with enrichment factors from 1780 to 155,217. Finally, it was coupled with gas chromatography–mass spectrometry (GC–MS) to develop an analytical method with a wide linear range (1–50,000 ng·L−1), low limits of detection (0.10–1.4 ng·L−1), good repeatability (0.83 %–7.5 %) and reproducibility (4.2 %–8.9 %). This work provides valuable insights into the structure-performance relationship of biochar, which is important for the design of high-performance biochar-based adsorbents and their applications in the environment.

Carbon allotropes and MXenes composites as superdurable nanofillers for polymer coatings: Emerging materials

Carbon allotropes, especially CNTs and GO, and MXenes are well-known for their filler and reinforced properties in polymer coatings. They fill the surface micropores and cracks of rapture coating structures and avoid the diffusion of corrosive species. They also avoid the direct attack of corrosive species by delaying their diffusion rate. However, carbon allotropes and MXenes manifest poor dispersibility as well as interfacial interactions that limit their use. Recent studies suggest that a suitable combination of carbon allotropes and MXenes (CAMs), synergistically enhanced their reinforcement property. The CAMs formulations manifest magnified durability as well as anticorrosive potential. As CAMs are chemically and thermally very stable, they can be used to formulate effective anticorrosive polymer-based coatings for high temperature application. This article aims to describe the challenges and opportunities of using CAMs as fillers in polymer coatings. The mechanism of reinforcement has also been reported along with future directions.

A Comparative Study on the Microstructure and Petrophysical Properties of Undeformed and Naturally Deformed Shales

Structural deformation is one of the main impacts responsible for understanding the hydrocarbon accumulation mechanism. Predicting its function in gas storage and migration in a microscopic scale is thus a significant issue in predicting reservoir quality. The purpose of this article is to make a comparative study on the microstructure and petrophysical properties of undeformed and naturally deformed shales developed in the Southeast Sichuan Basin. The results show that (1) organic pores, ranging from 10 to 200 nm, are more developed in undeformed shale, whereas carbonate solvopores, clay-hosted pores, and microfractures are dominant in deformed shale. (2) Undeformed shales have Dubinin–Radushkevich (DR) CO2 adsorbed contents ranging between 0.009 and 0.018 g, DR CO2 micropore surface areas of 3.90–15.59 m2/g, and Dubinin–Astakhov (DA) CO2 micropore volumes of 0.002 and 0.035 cc/g. Naturally deformed shales have larger DR CO2 adsorbed contents, DR CO2 micropore surface areas, and DA CO2 micropore volumes, typically in the ranges of 0.019–0.031 g, 13.15–20.97 m2/g, and 0.006–0.012 cc/g, respectively. (3) Undeformed shales have N2 adsorbed contents ranging between 1.94 and 6.03 cc/g, Brunauer–Emmett–Teller (BET) N2 mesopore and macropore surface areas of 0.55–7.35 m2/g, and Barrett–Joyner–Halenda (BJH) N2 mesopore and macropore volumes of 0.002 and 0.006 cc/g. Naturally deformed shales have larger N2 adsorbed contents, BET N2 mesopore and macropore surface areas, and BJH N2 mesopore and macropore volumes, typically in the ranges of 5.72–14.45 cc/g, 7.47–17.64 m2/g, and 0.005–0.015 cc/g, respectively. (4) All samples have a unimodal micropore size distribution with a distinct peak associated with a 1.5 nm micropore fraction and have a multimodal mesopore and macropore size distribution. Naturally deformed shales show more homogeneous pore size distribution curves with morphological consistency than undeformed shales, indicating that structural deformation can significantly influence pore structural heterogeneity. (5) Deformed shales exhibit higher porosity and permeability compared to the undeformed samples due to the open pore-fracture network associated with the inorganic pores and microfractures. Average porosity and permeability in deformed shales can be 1.8 and 15 times higher than those in the undeformed shales. We conclude that the microstructural heterogeneity from strong to weak and the changes of a relatively single organic pore-dominated pore system to complex pores and microfractures dominated the pore-fracture system within shales due to structural deformation being the key cause of the quantitatively and qualitatively studied microstructure and petrophysical property differences.

Influence of Humidity on Adsorption Performance of Activated Carbon

Activated carbon filter is the main equipment used to remove pollutants in the ventilation system in a nuclear power plant. Its main function is to remove radioactive iodine to minimize radioactive hazards against workers in the ventilation area. Periodic evaluation is a key step for verifying its operation effectiveness, further to ensure the safety and long-term operation. In this paper, by changing the micropore structure and surface chemical properties of activated carbon, its physicochemical properties and adsorption performance against methyl iodide under the high humidity working environment are studied. The results show that the adsorption performance of activated carbon on organic compound decreases significantly under the high humidity conditions; however, the combination of potassium iodide, triethylene diamine and functional groups on the activated carbon surface form stable chemical bonds and a new surface structure, which enhances the adsorption performance and stability of activated carbon against pollutants and makes it difficult to remove pollutants. The adsorption capacity of nuclear activated carbon can be restored to 80.7% of the initial capacity, and the adsorption performance can be obviously improved.

Plasma fibrin membranes loaded with bone marrow mesenchymal stem cells and corneal epithelial cells promote corneal injury healing via attenuating inflammation and fibrosis after corneal burns.

The shortage of corneal donors has prompted the development of tissue-engineered corneal grafts as an alternative solution. Currently, amniotic membranes with good biocompatibility are widely used as scaffolds for loading stem cells in the treatment of corneal injury. However, this approach has its limitations. In this study, BMSCs were induced to differentiate into corneal epithelial cells via direct contact co-culture, and platelet-poor plasma was used to prepare fibrin gels, which were compressed to remove excess liquid and then lyophilized to obtain plasma fibrin membranes (PFMs). A tissue-engineered corneal implant with PFMs as a scaffold loaded with BMSCs and corneal epithelial cells was designed and obtained. Scanning electron microscopy showed that PFMs have a uniformly distributed microporous surface that facilitates cell attachment and nutrient transport. The rheological results showed that the freeze-dried and rehydrated PFMs were more rigid than fresh membranes, which makes it easier to use them for transplantation after cell loading. The experimental results of a rat alkali burn cornea injury model showed that PFMs effectively reduced the inflammatory reaction, inhibited fibrosis, and accelerated the healing of corneal wounds. It was also found that some of the BMSCs were successfully implanted into the corneal injury site in rats and differentiated into corneal epithelial cells. These results demonstrate the potential of tissue-engineered corneal implants using BMSCs and corneal epithelial cells and PFMs as scaffolds as a new treatment option for corneal injury.

Textural, mineralogical and physico-chemical characterization of red clay of Tanout (Zinder-Niger) with a view to its valorization in water treatment

This study aims to determine the textural (specific surface, pore volume and pore size) and mineralogical characteristics of Tanout red clay of Zinder region (Niger) in order to have textural data allowing its use as an adsorbent. The methodology is based on textural analyzes (adsorption of N2 at 77 K by the Brunauer-Emmett-Teller method), mineralogical (X-ray fluorescence, X-ray diffraction, thermo-gravimetric analysis, scanning electron microscopy) and physicochemical (preliminary analyses). The results obtained show that the red clay has a specific surface of 418.4 m2.g-1 and 967.7 m2.g-1 calculated according to the BET and Langmuir methods respectively and a microporous surface of 540 m2.g- 1, with pore volume varying from 0.0389 to 0.2535 cm3.g-1 and pore size varying from 0.3675 to 5.423 nm calculated according to the methods (Barrett-Joyner-Halenda, Dubinin-Radushkevich, Dubinin -A, Horvath-Kawazoe and Saito-Foley). It has slit and cylindrical micro- pores. It has a slightly neutral pH in an aqueous medium and a high cation exchange capacity with low humidity and density, and is mainly composed of SiO2 (83.2%), Al2O3 (7.04%) and Fe2O3 (3.35%) with trace elements, the main ones being: Zr (2490 ppm), Sr (310.21 ppm), Cu (310.1 ppm), V (290.1 ppm) and Zn (140ppm). It consists essentially of Montmorillonite, illite and Kaolinite with impurities such as quartz and rutile. This clay has a high degree of crystallinity. These characteristics make it a promoter material that can be used as an adsorbent.

Regeneration of beaded activated carbon saturated with volatile organic compounds by a novel electrothermal swing adsorption system

A commercially available beaded activated carbon (KBAC) was selected for combination with a novel electrothermal swing system in examining the Joule heating effects on the physical and chemical properties of activated carbon and its adsorption regenerability at various regeneration temperatures (120, 140, and 160 °C) after saturation by toluene (TOL) and methylethylketone (MEK). The specific surface area (1278 m2 g− 1) and micropore volume (0.48 cm3 g− 1) for KBAC after one adsorption/desorption cycle were slightly reduced, while KBAC micropore surface area (1158 m2 g− 1) and micropore volume decreased significantly after six adsorption/desorption cycles. It can be inferred that the pores of KBAC, especially micropores, are blocked by heel buildup caused mainly by formation of cracked TOL and MEK coke generated by cyclic Joule heating. The desorption efficiencies of TOL-KBAC and MEK-KBAC (KBAC saturated with TOL and MEK, respectively) evaluated per the gravimetric method ranged from 55 to 80 and 85–90%, respectively, and both showed great correlation between regeneration temperature and desorption efficiency. Notably, the desorption efficiencies calculated from the integral method based on breakthrough curves were 8 and 16% lower than those directly obtained by the gravitational method for TOL-KBAC and MEK-KBAC, respectively. The larger difference in desorption efficiency evaluated by the two methods for MEK-KBAC is likely caused by the decomposition of MEK into CO or CO2, which was less prominent in TOL-KBAC. In the cyclic adsorption/desorption tests, the adsorption capacities of both TOL-KBAC and MEK-KBAC decreased after the 6-cycle electrothermal swing regeneration, such that TOL-KBAC adsorption capacity significantly reduced to around 50%, while that of MEK-KBAC retained around 70% of their respective original adsorption capacities. As aforementioned, heel buildup blocks the pores and leads to decreasing adsorption, especially for TOL.

Microporous surface as a new solution for stent surface modification: A review

The introduction of coronary stents into clinical practice has reduced repeated patient visits compared with balloon angioplasty alone. Also, drug-eluting stents substantially reduced the restenosis incidence. Therefore, later complications related to the implantation of a stent coated with a cytostatic-containing polymer became more relevant. The mechanism of late stent complications is multifactorial. It is mainly due to the body's response to the prolonged indwelling of the drug carrier polymer on the coronary stent's surface. There is a trend towards the return of polymer-free drug coating technologies, which are implemented through certain modifications of stent surfaces for better drug retention and proper drug distribution. It is mainly achieved using drug depots in various reservoirs: grooves, nanoparticles in the matrix compound, micropores, through and blind micro reservoirs, etc. New promising technologies for crystallizing cytostatic drugs or depositing them in specially designed reservoirs show good preclinical and clinical results, comparable or even superior to approved coronary stents. Micropores as carriers for antiproliferative agents on the stent surface are a promising direction to rejecting the use of polymers in stents.

Image recognition of cracks and the effect in the microporous layer of proton exchange membrane fuel cells on performance

Proton exchange membrane fuel cell (PEMFC) is considered as a potential power source for future automotive applications and microporous layer (MPL) is one of the core components. The cracks on the surface of microporous layer formed during the deposition process change the overall transport capacity and effect the output performance of fuel cells by regulating water management. In this work, the image recognition and feature extraction of microporous layer surface crack is proposed and elaborated in detail. The simple, fast and accurate method based on image recognition is realized by programming a regional connectivity algorithm and calculating the geometric features of the circumscribed geometry of the cracks. The application of artificial intelligence image processing technology at the micron level provides convenience for data analysis of crack distribution and improvement of microstructure. In this paper, scanning electron microscope (SEM) images of different carbon paper samples are taken, and the samples are tested under the same conditions to verify the feasibility and accuracy of the crack identification method, and to study the effect of cracks on the performance of fuel cells. The results prove that the image recognition algorithm can quickly and accurately identify the characteristics of cracks after Gaussian filtering and grayscale thresholding. Besides, it is found that cracks have impact on fuel cells and surface slender-shaped cracks with large area can improve the performance of fuel cells at high current densities. The method proposed in this paper can be used to improve the existing PEMFC design and quality check in process production by analyzing the local crack characteristics of the same sample and statistical data. In addition, the results of this paper are instructive for further water management research on microporous layer in fuel cells and can be used as a reference for practical applications.

Experimental and theoretical study of the adsorption of mixed low carbon alcohols and acids from Fischer Tropsch synthesis wastewater by activated carbon

To purify and recycle the low-carbon alcohols and acids in wastewater by a green method with high efficiency is of great significance in chemical engineering process, such as indirect coal liquefaction (Fischer Tropsch Synthesis, FTS), which produces a large amount of alcohol and acid-containing wastewater. Adsorption-desorption of low-carbon alcohols and acids in wastewater by activated carbon is a promising method for industrial application. The adsorption capacity of low-carbon alcohols and acids in activated carbons is closely related with their pore and surface properties. However, this was seldom studied due to the complex properties of carbon materials with different pore size, distribution and volume, as well as surface area and hydrophobicity. In this work, four commercial activated carbon materials (AC1 ∼ 4) with similar hydrophobicity and different pore and surface structure were chosen to explore the possible correlation of the adsorption capacity of C1-5 alcohols, C2-4 acids and FTS modeling wastewater. The batch method was used to investigate the adsorption capacity of AC1 ∼ 4 on low-carbon alcohols and acids as well as FTS modeling wastewater; while density functional theory (DFT) calculation was performed to investigate the adsorption energies of low-carbon alcohols and acids in carbon nanotubes with different pore sizes. Both the experimental and theoretical results indicate that the adsorption capacities of methanol, ethanol and acetic acid are strongly dependent on the ultra-micropores (<0.9 nm) due to their small molecular weight; and the adsorption capacity of pentanol is mainly determined by the surface areas due to its relatively high molecular weight and low polarity; while the adsorption capacities of C3-C4 alcohols and acids are well correlated with the microporous volume and surface area. In addition, and the adsorption capacities of acids were also related with the content of surface COOH species. AC2 has the highest adsorption capacity of mixed low-carbon alcohols and acids (196.2 mg/g) in FTS modeling wastewater due to its abundant ultra-micropore and high specific surface area. This work sheds light into the development of adsorbents with high adsorption capacity of low-carbon alcohols and acids, and provides solid experimental and theoretical support in the further purification of FTS wastewater and recovery of valuable chemicals.

Microstructural and physicochemical origins of electroless copper deposition on graphite enhanced by acid pretreatment

Acid treatment is the most widely used surface modification method for enhancing the electroless metal deposition (EMD) on carbon reinforcement materials (CRMs) for metal matrix nanocomposites. However, specific microstructural and physicochemical origins of the enhanced EMD on carbon surfaces by acid treatments have been rarely studied. Here, we investigated the effects of the nitric acid treatment on graphite, a prototypical combination of acid treatment and CRM, on the fidelity of Cu EMD and their structural and chemical origins. Complementary materials characterizations and density functional theory calculations revealed the acid-induced formation of broken C–C/CC graphitic bonds and resulting surface micropores on graphite; this enabled a uniform dispersion of catalytic Sn/Pd nanoparticles during pre-EMD sensitization/activation processes via spontaneous binding of Sn and Pd ions and, consequently, a much more uniform Cu layer EMD compared to the untreated graphite. We proposed a general mechanism illustrating how the acid-induced microstructural and chemical modifications of carbon surface affected the spatial uniformity of catalytic metal reduction during EMD and, finally, the quality of deposited metal layer. The results clearly reveal the origins of the enhanced EMD on carbon materials by acid treatments, providing guidelines for optimizing EMD on general CRMs for high-performance metal matrix nanocomposites.

Hierarchical porous metallic glass with strong broadband absorption and photothermal conversion performance for solar steam generation

The development of a strong light absorption absorber with a facile preparation process are crucial for some photothermal conversion applications, such as solar steam generation, photothermal catalysis and detectors. Here, a hierarchical structure based on microporous surface equipped with nanoporous layer is ingeniously designed and fabricated benefiting from the unique thermoplastic forming ability of metallic glasses by using the soluble clusters as template in less than 30 s. The presence of hierarchical porous structures induces multiple reflection of light and excites the plasmonic behavior of surface, achieving over 90% light absorption in the 380–20 µm wavelength range and the broad light incident angle from 0° to 70°, resulting in a remarkable photothermal conversion performance. Compared to conventional and existing absorber, the innovatively designed and fabricated metallic surface offers outstanding advantages in terms of light absorption range, heating rate and maximum temperature rise. Afterwards, the hierarchical porous structures for solar steam generation shows an evaporation efficiency of up to 94.2% and evaporation rate of 1.72 kg m−2 h−1 at 1 kW m−2. The design of unprecedented structure on metallic glass opens up a new strategy for solar energy harvesting, water treatment and other related fields.

Porosity Engineering towards Nitrogen-Rich Carbon Host Enables Ultrahigh Capacity Sulfur Cathode for Room Temperature Potassium-Sulfur Batteries.

Potassium-sulfur batteries (KSBs) are regarded as a promising large-scale energy storage technology, owing to the high theoretical specific capacity and intrinsically low cost. However, the commercialization of KSBs is hampered by the low sulfur utilization and notorious shuttle effect. Herein, we employ a porosity engineering strategy to design nitrogen-rich carbon foam as an efficient sulfur host. The tremendous micropores magnify the chemical interaction between sulfur species and the polar nitrogen functionalities decorated carbon surface, which significantly improve the sulfur utilization and conversion. Meanwhile, the abundant mesopores provide ample spaces, accommodating the large volume changes of sulfur upon reversible potassation. Resultantly, the constructed sulfur cathode delivers an ultrahigh initial reversible capacity of 1470 mAh g-1 (87.76% of theoretical capacity) and a superior rate capacity of 560 mAh g-1 at 2 C. Reaching the K2S phase in potassiation is the essential reason for obtaining the ultrahigh capacity. Nonetheless, systematic kinetics analyses demonstrate that the K2S involved depotassiation deteriorates the charge kinetics. The density functional theory (DFT) calculation revealed that the nitrogen-rich micropore surface facilitated the sulfur reduction for K2S but created a higher energy barrier for the K2S decomposition, which explained the discrepancy in kinetics modification effect produced by the porosity engineering.

Rational Design of Carbon-Based Porous Aerogels with Nitrogen Defects and Dedicated Interfacial Structures toward Highly Efficient CO2 Greenhouse Gas Capture and Separation.

CO2 capture from flowing flue gases through adsorption technology is essential to reduce the emission of CO2 to the atmosphere. The rational design of highly efficient carbon-based absorbents with interfacial structures containing interconnected porous structures and abundant adsorption sites might be one of the promising strategies. Here, we report the synthesis of nitrogen-doped carbon aerogels (NCAs) via prepolymerized phenol-melamine-formaldehyde organic aerogels (PMF) by controlling the addition amount of ZnCl2 and the precursor M/P ratio. It has been revealed that NCAs with a higher specific surface area and interconnected porous structures contain a large amount of pyridinic nitrogen and pyrrolic nitrogen. These would act as the intrinsic adsorption sites for highly effective CO2 capture and further improve the CO2/N2 separation efficiencies. Among the prepared samples, NCA-1-2 with a high micropore surface area and high nitrogen content exhibits a high CO2 adsorption capacity (4.30 mmol g-1 at 0 °C and 1 bar) and CO2/N2 selectivity (36.5 at 25 °C, IAST). Under typical flue gas conditions (25 °C and 1.01 bar), equilibrium gas adsorption analysis and dynamic breakthrough measurement associated with a high adsorption capacity of 2.65 mmol g-1 at 25 °C and 1.01 bar and 0.81 mmol g-1 at 25 °C and 0.15 bar. This rationally designed N-doped carbon aerogel with specific interfacial structures and high CO2 adsorption capacity, high selectivity, and adsorption performance remained pretty stable after multiple uses.

Pore structure and fractal characteristics of marine-continental transitional shales in the southern North China Basin

Research on marine-continental transitional shale in China is significant because this type of shale contains rich gas resources. The shale pore development, which is the key factor in determining the reservoir gas-bearing capacity, is complex. The organic matter (OM) content of the Shanxi and Taiyuan Formations shale in the southern North China Basin is medium to high, the mineral composition differs from that of other transitional shales, and the quartz content is higher than the clay content. The OM content and mineral composition exhibit a strong longitudinal heterogeneity. The pore types are mainly inorganic pores, and OM pores are less developed. The pore morphology is mainly parallel plate-like fissure pores, and there are a few ink-bottle-like pores composed of micro- and macropores. The specific surface area and total pore volume (TPV) of mesoporous-macropores are mainly controlled by mesoporous. The micropore volume is mainly controlled by micropores with sizes below 1.2 nm. Pore structure parameters and fractal dimension find that Shanxi and Taiyuan Formations shale has complex pore structure and rough pore surface. The fractal dimension D2 more accurately characterizes the roughness of the micropore surface. Compared with other shales, the micropore surface roughness of Shanxi and Taiyuan Formations shale is lower. The fractal dimensions and TPV do not correlate. The pore morphology and mineral characteristics of Shanxi and Taiyuan Formations shale leads to relatively low gas adsorption capacity and strong gas storage capacity, and is favorable for oil and gas migration. Due to the effects of compaction, macropores formed by quartz break and are filled with clay, resulting in a low daily gas production of the transitional shale in well MY1 after fracturing. The results provide references for the optimization of favorable reservoirs and the prediction of enrichment areas during transitional shale gas exploration.

Modification of Activated Carbon and Its Application in Selective Hydrogenation of Naphthalene.

The MoS2/ACx catalyst for hydrogenation of naphthalene to tetralin was prepared with untreated and modified activated carbon (ACx) as support and characterized by X-ray powder diffraction, Brunauer-Emmett-Teller, scanning electron microscopy, temperature-programmed desorption of ammonia, X-ray photoelectron spectroscopy, and scaning transmission electron microscopy. The results show that the modification of activated carbon by HNO3 changes the physical and chemical properties of activated carbon (AC), which mainly increases the micropore surface area of AC from 1091 to 1209 m2/g, increases the micropore volume of AC from 0.444 to 0.487 cm3/g, increases the oxygen-containing functional groups of AC from 5.46 to 7.52, and increases the acidity of catalysts from 365.7 to 559.2 mmol/g. The modified catalyst showed good catalytic performance, and the appropriate HNO3 concentration is very important for the modified of activated carbon. Among all the catalysts used in this study, the MoS2/AC3 catalyst could achieve the highest yield of tetralin. It can be attributed to the moderate acidity of the catalyst, reducing the cracking of hydrogenation products. Also, the proper hydrogenation activity of MoS2 and the appropriate increase of oxygen-containing functional groups on the surface of modified activated carbon are beneficial to the dispersion of active components on the support, increasing the yield of tetralin. The catalytic performance of MoS2/AC3 is better than that of MoS2/Al2O3 catalyst, and the two catalysts show different hydrogenation paths of naphthalene.