Presence Of Micropores Research Articles

Fluorescence visualization dynamics of carbonated water injection processes in homogeneous glass micromodels

Understanding the flow behavior of oil–water phases in porous media is crucial for revealing the kinetic mechanisms underlying oil–water movement. In this study, we designed and constructed a fluorescence visualization experimental platform for carbonated water injection (CWI). We evaluated the effects of nine distinct injection rates on oil production and CO2 sequestration capabilities using three types of homogeneous porous structure micromodels. The microscale oil–water seepage behavior at the pore scale was also explored. The experimental results indicate that optimally increasing the injection rate can improve displacement efficiency, whereas excessively high rates may lead to viscous and capillary fingering. The geometry of the micromodels, particularly the hexagonal matrix, demonstrates potential advantages in enhancing oil displacement due to its uniform flow paths. The capillary number (Ca) significantly influences oil droplet capture behavior within micromodels. For instance, micromodel A captures the largest ganglion area at low Ca values, with a noticeable reduction in average ganglion area as Ca increases. Conversely, micromodels B and C exhibit similar trends in ganglion size variation at high Ca values, suggesting a more uniform impact of pore structure on oil droplet capture behavior. At elevated Ca values, capillary forces exert a more uniform and controlled effect on oil droplet capture and release, minimizing size variability. Additionally, the injection rate plays a critical role in CO2 sequestration, with higher rates promoting convective mixing between CO2 and reservoir fluids, thereby enhancing dissolution and storage efficiency. The complexity of the pore structure, characterized by the presence of micropores and macropores, affects the dissolution kinetics and mobility of CO2, influencing sequestration efficiency. These experimental findings provide valuable insights into the dynamics of oil–water motion and the potential for enhanced oil recovery (EOR) and CO2 storage, offering essential guidance for optimizing CWI strategies in the petroleum industry.

3D Microporosity Characterizations in the Heterogeneous Middle Jurassic Tuwaiq Mountain Formation: Insights into an Unconventional Sweet Spot.

Carbonate microporosity can vary significantly across depositional lithofacies and cycles, owing primarily to the high degree of heterogeneity in their pore sizes, pore throat radius, geometry, and connectivity. This is further compounded by the complex diagenetic alterations during various stages of burial. In addition, the presence of micropores, which are abundant in carbonate rocks, but not visible using conventional techniques, is challenging to characterize. To address this issue, our study focused on the Middle Jurassic Tuwaiq Mountain Formation (TMF) due to its importance as an analogue to subsurface conventional and unconventional reservoirs. Here, we utilized eight samples and performed pore network modeling to quantify microporosity distribution and connectivity from high-resolution microcomputed tomography images of different microfacies (MF) in the TMF from both mud- and grain-dominated facies. These results were then validated with petrographic, SEM images, and porosity-permeability measurements. Our study revealed that, in the high-energy, grain-supported microfacies of the shallow lagoon depositional cycle, micropores dominated by interparticle and microvug types were abundant and well-connected, with mean pore and throat sizes of 7 and 4 μm. Conversely, micropores within the low-energy mud-dominated microfacies of the deep lagoon depositional cycle dominated by intraparticle and intercrystalline types were isolated and rarely connected, even at the microscale (1-4 μm in diameter, with an average of 2 μm). This result suggests that pore connectivity at the microscale is not always related to matrix porosity, and the pore connectivity is present in submicron scale, which goes against common concepts in unconventional carbonate reservoirs. Furthermore, our observations indicate that primary depositional processes play a major role in controlling the distribution and connectivity of the Tuwaiq Mountain Formation's microporosity, while diagenetic processes only have minor controls. Our study emphasizes the importance of characterizing microporosity and its connectivity in heterogeneous carbonate rocks, which may reduce the uncertainty in exploring the properties of complex carbonate reservoirs worldwide.

Synthesis of Activated Charcoal from Coconut Shell for the Removal of Crude Oil Spill

Crude oil spills have devastating effects on the environment, particularly aquatic ecosystems. The purpose of the present research is to determine whether dry coconut shells can be used as raw materials to make activated charcoal (AC) via pyrolysis and whether they can be utilized as natural sorbents to clean up crude oil spills. The UV-Vis spectrum of the synthesized CSAC shows distinct peaks at 230 and 260 nm, whereas the activated charcoal exhibits peaks at 231 and 261 nm. The FTIR spectra of the synthesized CSAC reveal a medium broad absorption peak at 3307.2 cm⁻¹, while the raw coconut shell's FTIR spectra show a medium sharp peak at 2945.3 cm⁻¹. The SEM images highlight the unique structural properties of CSAC, showcasing high porosity, varied pore sizes, rough surface topography, and the presence of micropores and mesopores. The chemical activation significantly increased the hydrophobicity of the adsorbent, creating CSAC with a much better adsorption capacity for crude oil removal, having a maximum adsorption capacity of 4840.0 mg/g and the highest percentage of crude oil removal at 99.9985%, as proven by batch experiments for different adsorbent dosages. The batch experimental results indicated that the percentage of crude oil removal increased with an increase in adsorbent dosage and contact time. Based on the correlation coefficients (R²) values (close to unity), it was generally observed that the plots match the Freundlich isotherm better than the Langmuir isotherm model. These findings have made the synthetic CSAC an attractive, useful, and environmentally friendly adsorbent.

A sol-gel templating route for the synthesis of hierarchical porous calcium phosphate glasses containing zinc

Hierarchical porous phosphate-based glasses (PPG) have great potential in biomedicine. Micropores (pore size <2 nm) increase the surface area, mesopores (pore size 2–50 nm) facilitate the absorption and diffusion of therapeutic ions and molecules making them ideal controlled delivery systems, while macropores (pore size >50 nm) facilitate the movement and diffusion of cells and fluids. In addition, the bioresorbability of PPG allows for their complete solubility in body fluid, alongside simultaneous formation of new tissue. Making PPG via the traditional melt-quenching (MQ) synthesis method used for phosphate-based glasses (PG), is not straightforward. Hence, we present here a route for preparing such glasses using a combination of sol-gel (SG) and templating methods. Hierarchical PPG in the P2O5–CaO–Na2O system with the addition of 1, 3 and 5 mol % of Zn2+ were prepared with pore dimensions ranging from the micro-to the macro scales using Pluronic 123 (P123) as a surfactant. The presence of micropores (0.30–0.46 nm), mesopores (1.75–9.35nm) and macropores (163–207 nm) was assessed via synchrotron-based Small-Angle X-ray Scattering (SAXS), with the presence of the latter two confirmed by Scanning Electron Microscopy (SEM). Structural characterisation performed using 31P solid state magic angle spinning nuclear magnetic resonance (MAS NMR) and Fourier Transform Infrared (FTIR) spectroscopies shows the presence of Q2, Q1 and Q0 phosphate species with a predominance of Q1 species in all compositions. Dissolution studies in deionised (DI) water confirm that controlled release of phosphates, Ca2+, Na+ and Zn2+ is achieved over a period of 7 days. In particular, the release of Zn2+ is proportional to its loading, making its delivery particularly easy to control.

Analysis of changes in shale mechanical properties and fault instability activation caused by drilling fluid invasion into formations

During the drilling process, the issue of drilling fluid loss can lead to changes in the mechanical properties of the formation, thereby altering the stress environment of nearby faults. In order to assess the risk of fault activation during drilling operations, the Ordos M area shale was selected as the research object. Mechanical experiments were conducted on rock samples immersed in water-based drilling fluid with a pressure differential of 2 MPa and a temperature of 50 °C. The changes in the mechanical properties of the shale before and after immersion in drilling fluid were determined. Based on the experimental results, combined with the spring combination model and fault activation theory, a quantitative evaluation of fault activation risk was conducted. The findings revealed that the shale in this region has a high clay content, demonstrating a certain level of water sensitivity. The presence of micro-pores and micro-fractures is well-developed, increasing the interaction probability between drilling fluids and clay minerals. After immersion in drilling fluid, there was a varied decline in all mechanical strengths of the shale. The elastic modulus is positively correlated with the shear strength and Coulomb stress of the fault plane. The Poisson’s ratio is positively correlated with the shear strength and negatively correlated with the Coulomb stress. The greater the internal friction and cohesion, the higher the shear strength of the fault plane, and the larger the friction coefficient, the smaller the Coulomb stress, resulting in a more stable fault.

Characterization and fractal characteristics of nano-scale pore structure in shale gas reservoirs: a case study of the deep Longmaxi Formation, Zigong region, Southern Sichuan Basin, China

Taking the Longmaxi deep-marine shale gas reservoir in Zigong region as the research target, this paper aimed to characterize the nano-scale pore structure and investigate the reservoirs’ heterogeneity based on fractal theory. By conducting a series of experimental studies, mainly including TOC, XRD, gas adsorption (N2 and CH4), we were able to clarify the main controlling factors for the heterogeneity of deep shale pore structure. Our results indicated that the deep marine shale possessed a significant amount of organic matter, as the average TOC value is 3.68%. The XRD analysis results show that quartz and clay were the main mineral types, and the total content of these two minerals averaged 77.5%. Positive correlations were observed between TOC and quartz, while TOC decreases as the clay mineral increases, this discovery indicating that quartz is biogenic. Based on FHH (Frenkele-Halseye-Hill) method, by using the LTNA adsorption isotherms, we took relative pressure P/P0=0.5 as the boundary, then two separate fractal dimension were deduced, D1 and D2 represent the fractal characteristics of small and large pores, respectively. Our study revealed that both D1 and D2 demonstrated positive correlations with N2 adsorption pore volume and adsorption specific surface area, while negatively correlated with the adsorption average pore diameter. Moreover, the two fractal dimensions showed positive associations with TOC and quartz and negative associations with clay. Additionally, D1 and D2 also demonstrated a positive correlation with Langmuir volume. The presence of micropores was found to significantly influence the formation of an irregular pore structure in shale. As the pore size decreased, the adsorption specific surface area increased, resulting in a more intricate pore structure, and the fractal dimension of the pores elevated, ultimately. This intricate structure is beneficial for the accumulation of shale gas. These research findings offer valuable insights for the comprehensive assessment of deep shale gas, and enrich our knowledge of enrichment mechanisms in deep shale gas reservoirs.

Effect of in-situ generated MgAl2O4 spinel on thermal shock resistance of magnesia-zirconia refractories

This study aims to advance the application of magnesia-zirconia (MgO–ZrO2) refractories in non-ferrous metal smelting furnaces by enhancing their thermal shock resistance. To fabricate MgO–ZrO2–MgAl2O4 refractories, tabular corundum particles and activated α-Al2O3 powder are integrated into MgO–ZrO2 refractories. The analysis of thermal shock resistance, phase composition, and microstructure of the samples was conducted to gain insights into the toughening mechanisms. The results reveal a substantial enhancement in thermal shock resistance with the addition of 15 wt% tabular corundum (1–0.5 mm) and activated α-Al2O3. Compared to samples without these additives, a notable increase of over 50.0 % in the ratio of residual cold modulus of rupture is shown. The enhancement in thermal shock resistance is primarily attributed to the in-situ generated MgAl2O4 spinel. This process involves volume expansion and increased thermal expansion mismatch, which induce microcrack toughening. Additionally, larger tabular corundum particles form in-situ MgAl2O4 spinel, causing crack deflection and branching, thus extending the crack propagation pathway. Furthermore, the presence of micropores in the spinel zone absorbs the energy required for crack propagation, thereby improving toughness and thermal shock resistance. Consequently, the MgO–ZrO2–MgAl2O4 refractories containing in-situ MgAl2O4 spinel with micropores are promising candidate for chrome-free refractories used in non-ferrous metal smelting furnaces.

Pore-structure control of porous carbon electrode materials and energy-storage performance in water-in-salt electrolytes

The pore structure of carbon-based materials and the voltage window of the electrolyte are two key factors affecting the energy density of carbon-based supercapacitors (SCs). In this paper, activated carbon materials of different pore sizes is successfully synthesized by chemical activation method by adjusting the mass ratio of ZnCl2 to sucrose, and successfully applied to construct SCs based on different electrolyte systems. As the specific surface area of the prepared porous carbon materials shows a tendency to increase and then decrease, reaching a maximum in the presence of micropores. Further summarizing the constitutive relationship between pore structure-electrochemical performance in the high-concentration electrolyte system, it is found that the normalized specific capacity is larger at smaller pore sizes, and with the increase of mesoporous proportion, the normalized specific capacity decreases and tends to be stable. In addition, the different strengths of solvation of anions and cations in the electrolyte, with the cations contributing more to the contrast, and the presence of mesopores providing ion transport channels to improve the efficiency of ion transport in porous materials, which provide directions for designing a suitable pore structure for highly concentrated salt electrolytes, as well as another way of optimizing the properties of carbon-based materials for SCs.

Assessment of the quality of root canal obturation of teeth with destructive forms of periodontitis using Silpex (SEM studies)

AIM. To evaluate the effectiveness of using the material Sealpex with gutta-percha pins using the lateral condensation method for permanent obturation of the root canals of teeth with periapical pathology and pathologically destroyed apical constriction.MATERIAL AND METHODS. The root canals of 94 teeth with destructive forms of periodontitis were filled with Sealpex. Depending on the degree of apical constriction, patients were divided into three groups. Follow-up of patients was carried out for 4 years.RESULTS. Using SEM, in 80% of cases, single micro cracks were detected between the dentin of the root canal wall and the sealer. In the area of wide apical openings, the fit of the material is loose, and it is removed beyond the root apex. The material diffuses into the root dentin. Statistical studies have shown a high percentage of successful treatment of destructive forms of periodontitis with the use of Sealpex.CONCLUSIONS. Endo-sealant extended beyond the apex of the root canal does not mean dense obturation of the apical foramen. The presence of micropores and microcracks in the endosealant can be regarded as evidence of poor sealing of the channel. The use of Sealpex is especially effective when filling teeth of groups, I and II with destructive forms of periodontitis

Controlled growth-dependent electrochemical behavior of cobalt and 1,3,5 benzene-tricarboxylic acid-based MOFs for efficient supercapacitor applications

This study investigates the synthesis and electrochemical performance of cobalt-BTC acid-based metal-organic frameworks (Co-MOFs) under different hydrothermal conditions. The crystal growth was controlled by varying the concentration of NaOH during synthesis, resulting in three Co-BTC MOF varieties (labeled as COMOFDW-0mM, COMOFDW-3mM, and COMOFDW-6mM). Exhaustive structural-microstructural characterizations, including X-ray diffraction (XRD), scanning electron microscopy (SEM), and N2 adsorption-desorption isotherms, elucidate the structural and morphological variation among these Co-BTC MOF varieties. The crystal structures of COMOFDW-0mM and COMOFDW-3mM exhibit similar laminar configurations, while COMOFDW-6mM shows major variations, such as changes in the coordination modes between BTC and cobalt complexes and differences in BTC plane directions in MOF crystal faces. SEM images reveal distinctive needle-like morphologies, and the as-synthesized crystals exhibit varying aspect ratios. Nitrogen adsorption-desorption isotherms indicate variations in the presence of micropores and mesoporosities, revealing microstructural differences. Electrochemical evaluations in a three-electrode system reveal superior performance for COMOFDW-6mM, with a maximum specific capacitance of 261.27 F/g, an energy density of 7.34 Wh/kg, and a maximum power density of 1325.2 W/kg under 2 M KOH electrolyte. Two-electrode coin cell measurements further validate its potential, maintaining competitive capacitance values. This systematic exploration of Co-MOFs not only elucidates the impact of growth conditions on crystal structures but also underscores the potential for tailoring electrochemical properties. Moreover, the findings present opportunities for further enhancements through composite strategies, opening new avenues for advancing MOFs in energy storage applications.

Enhancing PEO coating on TC6 alloy through in-situ synthesis of MoSe2—Towards more efficient wear-reducing lubrication and wear resistance

Plasma electrolytic oxidation (PEO) has demonstrated significant enhancements in the mechanical properties and corrosion resistance of titanium alloys. Despite these advantages, the presence of micropores and microcracks in the coating can still detrimentally impact tribological properties. This paper introduces a novel approach involving the in-situ growth of a surface structure. The resulting interface structure exhibits outstanding tribological properties under a load of 3 N and a speed of 1.5 cm/s. In contrast to prior studies, improvements are made to the electrical parameters and electrolyte formula of Plasma electrolytic oxidation, facilitating the in-situ growth of MoSe2. This results in the formation of a lubricating layer and a robust TiO2 ceramic coating with excellent adhesion. A systematic analysis of friction, wear characteristics, reveals that MoSe2 in situ grow on the surface of the PEO coating, within micropores, microcracks, and crater structures after hydrothermal treatment. This process significantly enhances the microporous structure of the coating, with the MoSe2 film forming a dense and uniform interlocking layer with the PEO lower layer. Dry friction test experiments demonstrate a 33.7% reduction in friction coefficient and a 29% decrease in wear rate compared to the PEO sample, indicating the synergistic effect between the MoSe2 film and the PEO coating.

Deformation behavior and crack mechanism of a first generation single-crystal Ni-based superalloys under thermomechanical fatigue loading

A research investigation was conducted to analyze thermomechanical fatigue (TMF) in a first-generation nickel-based single-crystal superalloy. The analysis was conducted within a temperature range of 450–950 °C while employing a strain ratio of −1 during two phases, in-phase (IP) and out-of-phase (OP). TMF life data were collected at varying mechanical strain amplitudes. The IP and OP TMF lifetimes were compared under identical strain conditions. A detailed analysis of the fractures and microstructures of the tested specimens was performed to investigate the crack mechanism. In the IP specimens, the formation of cracks closely followed the direction perpendicular to the principal stress within the material, which was primarily associated with the presence of micropores. Internal cracks tended to develop at locations with strain concentrations and subsequently propagate outward from the surface. The main mechanism behind these cracks was the interaction between creep and fatigue damage. Conversely, in the OP TMF specimens subjected to an oxide scale formed on the fracture surface, leading to fatigue cracking at multiple locations. The cracks gradually extended within the material before transitioning into the (111) crystallographic planes, where localized deformation bands occurred, affecting an area depleted of the γ' phase. This crack mechanism predominantly involved interactions between oxidation and fatigue. Among the various fatigue life prediction models, the Ostergren model exhibited strong agreement with the predicted data points for the fatigue life.

A step towards tuning the jute fiber structure and properties by employing sodium periodate oxidation and coating with alginate

This paper outlines a novel simple protocol for tuning the structure and properties of jute using sodium periodate (NaIO4) oxidation and coating with alginate. When compared to the raw jute, fabrics oxidized with a 0.2 or 0.4 % NaIO4 solution for 30–120 min exhibited an increased aldehyde group content (0.185 vs. 0.239–0.398 mmol/g), a significantly increased negative zeta potential (from −8.57 down to −20.12 mV), a slight disruption of fiber crystallinity, 15.1–37.5 % and 27.9–49.8 % lower fabric maximum force and stiffness, respectively. Owing to the removal of hydrophobic surface barrier, decreased crystallinity index and the presence of micropores on the fabrics' surfaces, oxidized fabrics have a 22.3–29.6 % improved ability for moisture sorption compared to raw fabric. Oxidized fabrics characterized by very long wetting times and excellent antioxidant activities (> 98 %), can find applications as hydrophobic packaging materials. To further extend the utilization of jute in biocarpet engineering such as water-binding geo-prebiotic supports, oxidized fabrics were coated with alginate resulting in 7.9–24.9 % higher moisture sorption and 352–660 times lower wetting times than their oxidized counterparts. This modification protocol has never been applied to lignocellulosic fibers and sheds new light on obtaining jute fabrics with tuned structure and properties intended for various applications.

Effect of microstructure in mesoporous adsorbents on the adsorption of low concentrations of VOCs: An experimental and simulation study

This study evaluated the adsorption of five volatile organic compounds (VOCs) on Opoka, precipitated silica, and palygorskite, to elucidate the effect of their pore size on VOCs adsorption. The adsorption capacity of these adsorbents is not only highly correlated with their surface area and pore volume, but also notably improved by the presence of micropores. The variation in adsorption capacity for different VOCs was primarily influenced by their boiling point and polarity. Palygorskite, which had the smallest total pore volume (0.357 cm3/g) but the largest micropore volume (0.043 cm3/g) among the three adsorbents, exhibited the highest adsorption capacity for all tested VOCs. Additionally, the study constructed slit pore models of palygorskite with micropores (0.5 and 1.5 nm) and mesopores (3.0 and 6.0 nm), calculated and discussed the heat of adsorption, concentration distribution, and interaction energy of VOCs adsorbed on different pore models. The results revealed that the adsorption heat, concentration distribution, total interaction energy, and van der Waals energy decrease with increasing pore size. The concentration of VOCs in 0.5 nm pore was nearly three times that in 6.0 nm pore. This work can also provide guidance for further research on using adsorbents with mixed microporous and mesoporous structures to control VOCs.

Membrane material based on acrylic emulsion and terry cloth for medical drapes

AbstractWaterproof “breathable” membrane materials were obtained using acrylic emulsion for the polymer layer and cotton terry cloth for the textile layer. Excellent physical, mechanical, and hygienic properties of polymer‐textile materials obtained by spraying the emulsion on the wrong side of the terry cloth, allow them to be used for medical and prophylactic bed linen. The resulting materials absorb a large amount of water (350%–366%), at the same time do not let liquid water through (water resistance—395–470 mm ), but have sufficient air and vapor permeability. The water‐absorbing and membrane properties of the obtained materials are due to their nature (hydrophilicity of cellulose fibers, hydrophobicity of polymethylacrylate) and structure (terry weaving of a textile fabric, the presence of micropores). Scanning electron microscope studies of the surface and cross section showed the capillary‐porous structure of the polymer layer and the material as a whole. When spraying an acrylic emulsion, a continuous polymer film is not formed; a hydrophobic polymer layer is located on the surface of individual fibers of a textile fabric. Another important advantage of the obtained membrane materials is that their water absorption, water resistance, and “breathing” properties are preserved after repeated washings.

Porosity distribution in the Devonian Antrim Shale: Controlling factors and implications for gas sorption

Unconventional reservoirs, such as oil and gas shales, are characterized by diverse and heterogeneous pore systems, and their detailed knowledge is critical for understanding fluid storage and transport mechanisms. The Devonian Antrim Shale in the Michigan Basin is an unconventional, primarily biogenic gas accumulation with a technical recoverable resource of 19.9 Tcf. While its general formation properties are known, the details of porosity distribution and pore morphology are lacking. This study provides a comprehensive description of the total porosity, pore size distribution, pore morphology and mineral associations for various members of the Antrim Shale sampled at three locations across the basin, and then investigates the factors controlling porosity distribution and the implications for gas sorption. Results indicate that the black-shale members, the Lachine and Norwood, are characterized by a lower porosity (0.1–2%) compared to the organic-lean members, the Paxton and Upper Antrim (2–7% porosity). Total porosity tends to decrease with the increase in organic content in the Antrim Shale as organic matter, in particular solid bitumen, occludes available pore space between mineral grains in the organic-rich black shale members. Organic matter displays little to no porosity of its own at the SEM resolution, but gas adsorption measurements indicate the presence of micropores (<2 nm), whose amount correlates positively to the total organic content. The Norwood member (TOC values up to 25%) is characterized by the largest share of micropores (up to 37% of the total porosity volume), while the organic-lean Paxton Member (TOC < 6%) has the least amount of microporosity (1–6%). Only the Lachine Member and select Upper Member samples showed larger organic matter pores, visible in the SEM images (∼50–100 nm). Mesopores (2–50 nm) are the dominant pore size group in the Antrim Shale, forming 45% to 76% of the pore space, and most of the pores are interparticle and intraparticle pores in and around clays, quartz, feldspar and pyrite grains. No single mineral component influences the total porosity distribution, but clay content exhibits a weak positive correlation to the meso-macro porosity. As microporosity is known to contribute the most to gas adsorption capacity of unconventional reservoirs, TOC appears to be most important factor controlling both CH4 and CO2 storage potential of the Antrim Shale. The Norwood Member, characterized by the highest TOC and microporosity volume as well as surface area of the micropores, is predicted to have the highest gas adsorption capacity but direct sorption measurements will be needed to confirm that. This study highlights some important differences with previous observations about porosity relationship to organic and mineral components of shale reservoirs, and expands the understanding of shale pore systems in the low-maturity range of organic-rich shales.

Effective toluene removal from aqueous solutions using fast pyrolysis-derived activated carbon from agricultural and forest residues: Isotherms and kinetics study

In this study, the production and characterization of activated carbons (ACs) from agricultural and forest residue using physical activation are discussed. Biomass-based biochars produced during fast pyrolysis process is introduced as alternative precursors to produce AC and the integrated process for the co-production of porous adsorbent materials from biochar via the fast pyrolysis process is suggested. Moderate surface areas and good adsorption capacities were obtained from switchgrass (SWG) and pine tops (PT) based AC. The surface areas were 959 and 714 m2/g for SWG- and PT-based AC, respectively. The adsorption capacities using toluene as pollutant for two model systems of 180 and 300 ppm were measured and ranged between 441-711 and 432–716 mg/g for SWG-based and PT-based AC, respectively. The nitrogen adsorptive behavior, Lagergren pseudo-second-order kinetic (PSOK) model and kinetics isotherms studies describe a heterogeneous porous system, including a mesoporous fraction with the existence of a multilayer adsorption performance. The presence of micropores and mesopores in SWG- and PT-based AC suggests potential commercial applications for using pyrolytic biochars for AC production.

Porous cellulose microspheres loaded with dry Nile water algae for removal of MB dye and copper ions from aqueous media

AbstractLow‐cost‐effective applied technologies for water and wastewater treatment, such as microalgae, have growing attention due to their mutual benefit in wastewater treatment and for valuable algae biomass production. A newly constructed Nile water algae cross‐linked cellulose microsphere (NACS) was applied by functionalization of cross‐linked cellulose acetate with dry Nile water algae forming an efficient adsorptive microsphere. The adsorption capacity of microspheres was evaluated for the removal of basic dye (Methylene blue: MB) and heavy metal copper ions (Cu+2). The molecular structure revealed that the prepared microspheres have several functional groups and elements that have a high affinity for heavy metals and dye removal; furthermore, the morphological structure emphasizes this removal affinity by the presence of micropores at the surface of the microsphere. The results of maximum biosorption conditions showed both MB and Cu through the microsphere were 20 mg/L MB and (10 and 20) mg/L Cu concentrations, 2 g/L of adsorbent dose, pH (MB = 6 and Cu = 5.5), and contact time of 60 min. The maximum adsorption capacities (qmax) were significantly enhanced at 200 and 153.2 mg/g for MB and Cu (II), respectively. The possibility of removal, recovery, and reuse of MB by prepared microsphere was efficiently achieved.

Tuning the pore size distribution of Ti3C2Tx porous film for high capacity supercapacitor electrode

The closely restacked MXene nanosheets obstruct electrolyte ion transfer in electrodes, limmiting the electrochemical performance at a high charging-discharging rate. Although various 3D porous structures have been constructed, size effect of porous MXenes electrodes has been rarely studied. Herein, the classical metal ion-assisted method was used to fabricate 3D porous MXene films. The pore size distribution was changed by adjusting the cation valency. Noteworthy, when the mesoporous pore size distribution is in the range of 5 ∼ 10 nm, the porous structure can significantly improve the electrochemical performance and the presence of micropores can increase the proportion of surface capacitance. As a result, the porous Ti3C2Tx film treated by Mg2+ showed outstanding electrochemical performance, with both high capacity (420F/g at 2 mV/s) and good cyclic stability (94.4% retention after 5000 cycles). This work presents a study on how pore size distribution of porous MXene film effects the electrochemical performance and provides a reference for the design of 3D porous MXene electrodes.

Analytical study of Brinkman–Bénard convection in a bidisperse porous medium: Linear and weakly nonlinear study

Linear and weakly nonlinear stability analyses of Brinkman–Bénard convection of a Newtonian fluid saturating a bidisperse porous medium (BDPM) are made. Local-thermal-non-equilibrium (LTNE) is assumed between the fluid and the porous spheres (micro-pores) that make up the macro porous medium. Two coupled linear momentum equations are considered one each for the macro- and micro-pores. Results of mono-disperse porous medium (MDPM) with solid spheres are recovered as a limiting case of the present study. Further, in the case of both types of porous media considered the results of Darcy–Bénard and Brinkman–Bénard convection are extracted under suitable limiting procedures. To keep the work analytical, we reduce the intractable hexa-modal Lorenz model with four quadratic nonlinearities into the tractable mono-modal Stuart–Landau equation (SLE) with cubic and quintic nonlinearities. Subcritical instability is discounted in the study thereby suggesting that cubic SLE and cubic–quintic SLE both expound similar results qualitatively. The concept of a BDPM is shown to be meaningful only when the pores are not large, and when they are very small, then the MDPM assumption applies. Similar observation can be made when the ratio of permeabilities is large. The presence of micro-pores does not alter the size of the convective cell significantly at the onset. The present study reiterates the findings of several earlier works.