Role of micropores within minerals in retardation of mass transfer by matrix diffusion and sorption in granitic rock.

Understanding the mass transfer characteristics of matrix diffusion and sorption is important in the safety assessment of geological disposal of high-level radioactive waste in crystalline rock (granite) by contributing to radionuclide retardation through mass transfer within the rock body. We present a comparative discussion of the effective diffusion coefficient (De), porosity, and petrological data for rock samples collected from the Toki Granite in central Japan, to evaluate the role of micropores within minerals in retardation by matrix diffusion and sorption in granitic rocks. De was derived from the through-diffusion experiments using uranine, barium, strontium, and chloride ions as tracers. Petrological data consist of the fracture frequency, the extent of hydrothermal alteration in the minerals, the micropore volume in the minerals, and the three-dimensional modal mineralogy (mineral assemblage and ratio) for the target rock samples. The relationship between the De, porosity, and petrological data has the following implications: 1) Micropores in minerals related to the alteration act as 'storage pores' that contribute to retardation due to matrix diffusion and sorption; 2) Once the uranine, cations (Ba2+ and Rb+), and anion (Cl-) penetrate the micropores in the minerals through matrix diffusion, the cations are sorbed on the micropore surfaces, whereas the uranine and conservative chloride anion is trapped at the end of the micropore network, resulting in retardation; 3) Regions with a high fracture frequency are associated with not only active advection-dispersion through fractures, but also retardation due to matrix diffusion and sorption; 4) The grain-boundary pores between colorless minerals act as 'transport pores' owing to matrix diffusion, and the retardation within grain-boundary pores is less than that within micropores in minerals.

Extent of As(III) versus As(V) adsorption on iron (oxyhydr) oxides depends on the presence of vacancy cluster-like micropore sites: Insights into a seesaw effect.

Iron (oxyhydr)oxides are ubiquitous in terrestrial environments and play a crucial role in controling the fate of arsenic in sediments and groundwater. Although there is evidence that different iron (oxyhydr)oxides have different affinities towards As(III) and As(V), it is still unclear why As(V) adsorption on some iron (oxyhydr)oxides is larger than As(III) adsorption, while it is opposite for other ones. In this study, six typical iron (oxyhydr)oxides are selected to evaluate their adsorption capacities for As(III) and As(V). The characteristics of these iron minerals such as morphology, arsenic adsorption species, and pore size distribution are carefully examined using transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), positron annihilation lifetime (PAL) spectroscopy, and X-ray absorption spectroscopy (XAS). We confirm a seesaw effect occurred in different iron minerals for As(III) and As(V) immobilization, i.e., at pH 6.0, adsorption of As(V) on hematite (0.73 µmol m-2) and magnetite (0.33 µmol m-2) is higher than for As(III) (0.61 µmol m-2 and 0.27 µmol m-2, respectively), for goethite and lepidocrocite it is almost equal, while As(III) sorption on ferrihydrite (5.77 µmol m-2) and schwertmannite (28.41 µmol m-2) showed higher sorption than As(V) (1.53 µmol m-2 and 12.99 µmol m-2, respectively). PAL analysis demonstrates that ferrihydrite and schwertmannite have a large concentration of vacancy cluster-like micropores, significantly more than goethite and lepidocrocite, followed by hematite and magnetite. The difference of adsorption of As(III) and As(V) to different iron (oxyhydr)oxides is due to differences in the abundance of vacancy cluster-like micropore sites, which are conducive for smaller size As(III) immobilization but not for larger size of As(V). The findings of this study provide novel insights into a seesaw effect for As(III) and As(V) immobilization on naturally occurring iron mineral.

Effects of pore characteristics on CO2 adsorption performance of coal slime with different metamorphic degrees.

With the rapid development of Carbon Capture, Utilization and Storage (CCUS) technology, it is necessary to explore the feasibility of coal slime as a porous carbon material for CO2 capture. In this paper, scanning electron microscopy (SEM) was used to observe the morphological characteristics of coal slime samples with different metamorphic degrees, and the pore structure of coal slime was explored by low temperature N2 adsorption and low-pressure CO2 adsorption experiments. The pore distribution characteristics were analyzed, and the adsorption law of different metamorphic degrees were summarized through CO2 isothermal adsorption experiments. The results showed that: The specific surface area (SSA) and pore volume (PV) of the mesopores of the coal slime exhibited a U-shaped distribution with coal rank, and are much smaller than that of its micropores. Micropores less than 2 nm are the main adsorption space of coal slime, its PV accounted for 59%, 60%, 71%, and SSA accounted for 92%, 93%, 95%, obviously, which are dominant at all stages. The linear correlation fitting coefficients R2 between the limiting adsorbed amount a of CO2 and the micropores PV and the SSA were up to 0.830 and 0.887, respectively. The coal slime has good adsorption performance for CO2. Based on the Langmuir model to fit the limit adsorption amount, a-value can reach 41.774 cm3 g-1, 32.072 cm3 g-1, 38.457 cm3 g-1 at 303 K with the increase of Rmax. Studying the impact of coal slime on CO2 adsorption performance provides a theoretical basis for the subsequent preparation of energy storage materials and is of great significance for the safe, efficient and economic capture and sequestration of CO2, to alleviate the serious situation of the environment and realizing the dual-carbon goal.

Comparative Analysis of Woody Biomass Fly Ash and Class F Fly Ash as Supplementary Cementitious Materials in Mortar.

Biomass fly ash is a sustainable, eco-friendly cement substitute with economic and performance benefits, being renewable compared to coal fly ash. This study examines using biomass fly ash (BFA) as a sustainable cement substitute, comparing it with Class F fly ash (CFA). With a water-binder ratio of 0.5 and replacement rates of 10%, 15%, 20%, 25%, and 30% (by mass), the research highlights BFA's promising applications. BFA and CFA were mixed into cement paste/mortar to analyze their reactivity and properties, with hydration products CH and C-S-H evaluated at 7, 28, and 91 days. Compressive strength, micro-pore structure, and drying shrinkage (assessed from 7 to 182 days) were tested. Results showed BFA had similar pozzolanic reactions to CFA at later stages. While compressive strength decreased with higher BFA replacement rates, early-stage performance matched CFA; growth was CFA-10 (18 MPa) and BFA-10 (17.6 MPa). BFA mortars exhibited slightly better deformation properties. BFA-30 cement had superior performance, with a lower drying shrinkage rate of 65.7% from 14 to 56 days compared to CFA-10's 73.4% and a more stable shrinkage growth rate decrease to 8.4% versus CFA-10's 6.4% after 56 days. This study concluded that BFA, usable without preprocessing, performed best at a 10-15% replacement rate.

Targeted Stimulation of Micropores by CS2 Extraction on Molecular of Coal.

The targeted stimulation of micropores based on the transformation of coal's molecular structure is proposed due to the chemical properties and difficult-to-transform properties of micropores. Carbon disulfide (CS2) extraction is used as a targeted stimulation to reveal the internal evolution mechanism of micropore transformation. The variations of microcrystalline structures and micropores of bituminous coal and anthracite extracted by CS2 were analyzed with X-ray diffraction (XRD), low-temperature carbon dioxide (CO2) adsorption, and molecular simulation. The results show that CS2 extraction, with the broken chain effect, swelling effect, and aromatic ring rearrangement effect, can promote micropore generation of bituminous coal by transforming the microcrystalline structure. Furthermore, CS2 extraction on bituminous coal can decrease the average micropore size and increase the micropore volume and area. The aromatic layer fragmentation effect of CS2 extraction on anthracite, compared to the micropore generation effect of the broken chain effect and swelling effect, can enlarge micropores more remarkably, as it induces an enhancement in the average micropore size and a decline in the micropore volume and area. The research is expected to provide a theoretical basis for establishing reservoir stimulation technology based on CS2 extraction.

Progress in the Preparation and Application of Breathable Membranes.

Breathable membranes with micropores enable the transfer of gas molecules while blocking liquids and solids, and have a wide range of applications in medical, industrial, environmental, and energy fields. Breathability is highly influenced by the nature of a material, pore size, and pore structure. Preparation methods and the incorporation of functional materials are responsible for the variety of physical properties and applications of breathable membranes. In this review, the preparation methods of breathable membranes, including blown film extrusion, cast film extrusion, phase separation, and electrospinning, are discussed. According to the antibacterial, hydrophobic, thermal insulation, conductive, and adsorption properties, the application of breathable membranes in the fields of electronics, medicine, textiles, packaging, energy, and the environment are summarized. Perspectives on the development trends and challenges of breathable membranes are discussed.

Constructing Microporous Ion Exchange Membranes via Simple Hypercrosslinking for pH-Neutral Aqueous Organic Redox Flow Batteries.

Ion exchange membranes (IEMs) play a critical role in aqueous organic redox flow batteries (AORFBs). Traditional IEMs that feature microphase-separated microstructures are well-developed and easily available but suffer from the conductivity/selectivity tradeoff. The emerging charged microporous polymer membranes show the potential to overcome this tradeoff, yet their commercialization is still hindered by tedious syntheses and demanding conditions. We herein combine the advantages of these two types of membrane materials via simple in situ hypercrosslinking of conventional IEMs into microporous ones. Such a concept is exemplified by the very cheap commercial quaternized polyphenylene oxide membrane. The hypercrosslinking treatment turns poor-performance membranes into high-performance ones, as demonstrated by the above 10-fold selectivity enhancement and much-improved conductivities that more than doubled. This turn is also confirmed by the effective and stable pH-neutral AORFB with decreased membrane resistance and at least an order of magnitude lower capacity loss rate. This battery shows advantages over other reported AORFBs in terms of a low capacity loss rate (0.0017 % per cycle) at high current density. This work provides an economically feasible method for designing AORFB-oriented membranes with microporosity.

Machine learning and experimentally exploring the controversial role of nitrogen in CO2 uptake by waste-derived nitrogen-containing porous carbons.

Waste-derived nitrogen-containing porous carbons were widely accepted as promising carbon capture materials. However, roles of nitrogen in CO2 uptake were highly controversial, posing a challenge in designing high CO2 uptake porous carbons. Herein, nitrogen-containing species was firstly introduced into machine learning (ML) models to uncover the complex relationship of nitrogen, micropore and CO2 uptake by combining ML models, DFT computations and experiments. The results revealed that micropore volume (Vmicro) was the most important property influencing CO2 uptake, but was not the only determinant factor. Nitrogen-containing species (pyrrolic/pyridonic-N (N5) and pyridinic-N (N6)) rather than total nitrogen content, also played an essential role. On the one hand, they can enhanced CO2 adsorption by Lewis acid-base and hydrogen bonding. On the other hand, they promoted development of micropores by participating in activation reactions. The model further indicated that excessive N5 (>1.5 wt%) or N6 (>1.7 wt%) led to restriction on developments of micropores, which was attributed to enlargement of pore size, collapses or blockage of micropores. The double edged-sword effect of N5 and N6 on changes of microporous structures was responsible for the long-standing controversy over nitrogen. The result was further verified by synthesizing eight porous carbons with different textural and chemical properties. This study provided not only a new perspective for resolving the controversy of nitrogen in CO2 uptake, but also a graphical user interface prediction software meaningful for designing porous carbons.

Apicomplexa micropore: history, function, and formation.

The micropore, a mysterious structure found in apicomplexan species, was recently shown to be essential for nutrient acquisition in Plasmodium falciparum and Toxoplasma gondii. However, the differences between the micropores of these two parasites questions the nature of a general apicomplexan micropore structure and whether the formation process model from Plasmodium can be applied to other apicomplexans. We analyzed the literature on different apicomplexan micropores and found that T. gondii probably harbors a more representative micropore type than the more widely studied ones in Plasmodium. Using recent knowledge of the Kelch 13 (K13) protein interactome and gene depletion phenotypes in the T. gondii micropore, we propose a model of micropore formation, thus enriching our wider understanding of micropore protein function.

Direct carbonization of cellulose toward hydroxyl-rich porous carbons for pseudocapacitive energy storage.

Designing carbon materials with specific oxygen-containing functional groups is very attractive for the precise decoration of carbon electrode materials and the basic understanding of specific charge storage mechanisms, which contributes to the further development of high-performance carbon materials for energy storage and conversion applications. In this contribution, a hydroxyl-rich micropore-dominated porous carbon material was obtained by direct carbonization of cellulose. The content of oxygen atoms in hydroxyl form in the obtained carbon is nearly 6 at.%. With the pyrolysis temperature changed, the macroscopic morphology, the specific surface area, surface functional groups, and graphitization degree of the carbon materials were changed strongly. Besides, the carbon material obtained with a carbonization temperature of 900 °C (C9) showed enhanced specific capacitance in sulfuric acid, sodium hydroxide, and sodium sulfate aqueous electrolytes, which mainly originates from the contribution of pseudocapacitance. The pseudocapacitance mainly depends on the presence of surface hydroxyl functional groups. Besides, the pseudocapacitance value of C9 material in neutral electrolytes (151.34 F g-1) is about twice that in acidic (75.9 F g-1) and alkaline (75.78 F g-1) electrolytes.

Preferentially Biodegradable Gypsum Fibers Endowing Invisible Microporous Structures and Enhancing Osteogenic Capability of Calcium Phosphate Cements.

It is known that hydroxyapatite-type calcium phosphate cement (CPC) shows appreciable self-curing properties, but the phase transformation products often lead to slow biodegradation and disappointing osteogenic responses. Herein, we developed an innovative strategy to endow invisible micropore networks, which could tune the microstructures and biodegradation of α-tricalcium phosphate (α-TCP)-based CPC by gypsum fibers, and the osteogenic capability of the composite cements could be enhanced in vivo. The gypsum fibers were prepared via extruding the gypsum powder/carboxylated chitosan (CC) slurry through a 22G nozzle (410 µm in diameter) and collecting with a calcium salt solution. Then, the CPCs were prepared by mixing the α-TCP powder with gypsum fibers (0-24 wt %) and an aqueous solution to form self-curing cements. The physicochemical characterizations showed that injectability was decreased with an increase in the fiber contents. The µCT reconstruction demonstrated that the gypsum fiber could be distributed in the CPC substrate and produce long-range micropore architectures. In particular, incorporation of gypsum fibers would tune the ion release, produce tunnel-like pore networks in vitro, and promote new bone tissue regeneration in rabbit femoral bone defects in vivo. Appropriate gypsum fibers (16 and 24 wt %) could enhance bone defect repair and cement biodegradation. These results demonstrate that the highly biodegradable cement fibers could mediate the microstructures of conventional CPC biomaterials, and such a bicomponent composite strategy may be beneficial for expanding clinical CPC-based applications.

Contribution of micropores in porous zirconia spheres to high optical transparency of dental resin composites.

Transparency to UV-Vis light and radiopacity of dental resin composites containing zirconia (ZrO2) fillers were investigated. The transparency of the resin composite containing porous ZrO2 spheres was much higher than that containing irregularly shaped ZrO2 particles. Calcination of the porous ZrO2 spheres at high temperatures led to dramatically reduced specific surface areas and pore volumes. The transparency of the resin composite containing the calcined porous ZrO2 spheres drastically decreased as the calcination temperature increased. Then, the enhanced UV-Vis transmittance of the resin composite containing porous ZrO2 spheres is attributed to the concentration and physical characteristics of the pores. The radiopacity of the resin composites containing porous ZrO2 spheres increased slightly with increasing calcination temperature. This study revealed that the internal structure of the ZrO2 fillers mainly influenced in the UV-Vis light transmittance of the resin composites.

Outcomes of thoracic endovascular aortic repair with physician-manufactured partial micropore stent grafts for aortic arch pathologies.

OBJECTIVE: Thoracic endovascular aortic repair (TEVAR) has been used extensively in the management of thoracic aortic diseases. Numerous efforts have been made to enhance clinical outcomes through the use of stent grafts. This study aimed to investigate the effectiveness and safety of physician-manufactured partial micropore stent grafts (PSMGs) in TEVAR. METHODS: Between December 2017 and June 2022, data were collected from 56 patients who underwent TEVAR using physician-manufactured PSMGs. The evaluation encompassed technical success, perioperative and follow-up morbidity and mortality, stroke incidence, and branch artery patency. RESULTS: In this investigation, 56 patients received treatment with physician-manufactured PSMGs. Of these patients, 46 were male, with a mean age of 62.1 ± 11.2 years. Aortic pathologies comprised aortic dissection (n = 31 [55.4%]), aortic aneurysms (n = 10 [17.9%]), penetrating aortic ulcer (n = 8 [14.3%]), and intramural hematoma (n = 7 [12.5%]). During a median follow-up of 18 months (interquartile range, 13-25 months), the stroke rate, supra-aortic branch patency rate, and endoleak rate were 0%, 100%, and 7.1%, respectively. There were no occurrences of all-cause mortality, stroke, or the necessity for open conversion. CONCLUSIONS: TEVAR with physician-manufactured PSMGs is a viable alternative for addressing aortic arch pathologies in proficient medical centers. The approach demonstrates favorable branch patency, a low complication rate, and minimal postoperative mortality.

Research Advances in Wood Composites in Applications of Industrial Wastewater Purification and Solar-Driven Seawater Desalination.

In recent years, the ecosystem has been seriously affected by sewage discharge and oil spill accidents. A series of issues (such as the continuous pollution of the ecological environment and the imminent exhaustion of freshwater resources) are becoming more and more unmanageable, resulting in a crisis of water quality and quantity. Therefore, studies on industrial wastewater purification and solar-driven seawater desalination based on wood composites have been widely considered as an important development direction. This paper comprehensively analyzes and summarizes the applications of wood composites in the fields of solar-driven seawater desalination and polluted water purification. In particular, the present situation of industrial wastewater containing heavy metal ions, microorganisms, aromatic dyes and oil stains and related problems of solar-driven seawater desalination are comprehensively analyzed and summarized. Generally, functional nanomaterials are loaded into the wood cell wall, from which lignin and hemicellulose are selectively removed. Alternatively, functional groups are modified on the basis of the molecular structure of the wood microchannels. Due to its three-dimensional (3D) pore structure and low thermal conductivity, wood is an ideal substrate material for industrial wastewater purification and solar-driven seawater desalination. Based on the study of objective conditions such as the preparation process, modification method and selection of photothermal conversion materials, the performances of the wood composites in filtration, adsorption and seawater desalination are analyzed in detail. In addition, this work points out the problems and possible solutions in applying wood composites to industrial wastewater purification and solar-driven seawater desalination.

New Mechanism via Dichlorocarbene Intermediate for Activated Carbon-Mediated Reductive Dechlorination of Carbon Tetrachloride by Sulfide in Aqueous Solutions.

Although activated carbon (AC) is widely used as an adsorbent and barrier for contaminated sediment remediation, little attention has been paid to its mediation effects on reductive dechlorination of chlorinated solvents by commonly presenting sulfide. Here, we reported that highly porous, graphitized AC (250 mg L-1) suspended in deoxygenated aqueous solutions could increase the pseudo-first-order rate constant of sulfide-induced dechlorination of carbon tetrachloride (CCl4) by more than 1 order of magnitude. Carbon disulfide (CS2) was the only main product, with no production of chloroform or dichloromethane. The minimum promotion of CCl4 reduction observed with electro-conductive but nonporous graphite and a microporous but electro-insulative resin (XAD-4) indicates that graphitic carbons and micropores both play key roles in AC-mediated dechlorination of CCl4 by sulfide. The detection of dichlorocarbene (:CCl2) by free radical trapping experiments combined with the high suitability of the Langmuir-Hinshelwood model led us to propose a new mediation mechanism: CCl4 molecules adsorbed within the deep regions of AC micropores formed by graphitic carbons accept two electrons transferred from sulfide to form :CCl2, which is impeded from hydrolysis and hydrogenolysis by the hydrophobic micropore and further reacts with sulfide to generate CS2. Consistently, the production of :CCl2 was very low when AC was replaced with graphite or XAD-4. The proposed mechanism was further validated by the enhanced mediation effects of another two carbonaceous materials (template-synthesized mesoporous carbon and covalent triazine-based framework) that are electro-conductive and have well-developed micropore structures. These findings highlight the importance of pore properties of carbonaceous materials as mediators or catalysts for reductive dechlorination reactions and shed light on the development of coupled adsorption-reaction systems for remediation.

Porous Structure and Fractal Dimensions of Activated Carbon Prepared from Waste Coffee Grounds.

The present work reports the results of a systematic study on the evolution of the morphological properties of porous carbons derived from coffee waste using a one-pot potassium-hydroxide-assisted process at temperatures in the range of 400-900 °C. Raw materials and obtained carbons were studied by TG, DTG, SEM and nitrogen adsorption porosimetry. The decomposition temperature ranges for hemicellulose, cellulose and lignin as the main component of the feedstock have been established. It is shown that the proposed method for the thermochemical treatment of coffee waste makes it possible to obtain activated carbon with a controllable pore size distribution and a high specific surface area (up to 1050 m2/g). A comparative study of the evolution of the distribution of pore size, pore area and pore volume has been carried out based on the BJH and NL-DFT (slit-like pores approximation) methods. The fractal dimension of the obtained carbons has been calculated by Frenkel-Halsey-Hill method for single-layer and multilayer adsorptions.

Preparation of Microporous Molding Activated Carbon Derived from Bamboo Pyrolysis Gasification Byproducts for Toluene Gas Adsorption.

The effective utilization of charcoal and tar byproducts is a challenge for pyrolysis gasification of bamboo. Herein, the bamboo tar was modified via polymerization and acted as a new adhesive for the preparation of excellent bamboo-charcoal-derived molding activated carbon (MBAC). As compared with pristine tar and other adhesives, the aromatization of tar with phenol increased its molecular weight, oxygenic functional groups, and thermal stability, leading to the decreased blocking impact of charcoal pore and improved bonding and pyrolytic crosslinking effect between charcoal particles. These further contribute to the high mechanical strength, specific surface area, pore volume, and amount of oxygenic functional groups for fabricated MBAC. Owing to the high microporous volume of MBAC, it exhibited 385 mg·g-1 toluene and 75.2% tetrachloride gas adsorption performances. Moreover, the pseudo-first-order, pseudo-second-order, and Bangham models were used to evaluate the kinetic data. The toluene adsorption process conforms to the Bangham kinetic model, suggesting that the diffusion mechanism of toluene adsorption mainly followed intraparticle diffusion.

Effect of Heat Treatment on the Microstructure and Mechanical Properties of 18Ni-300 Maraging Steel Produced by Additive-Subtractive Hybrid Manufacturing.

The present work investigates the effectiveness of two heat treatment cycles-solution treatment + aging (STA) and direct aging (DA)-on optimizing the microstructure and enhancing the mechanical properties of 18Ni-300 maraging steel (300 MS) produced by additive-subtractive hybrid manufacturing (ASHM). The STA treatment led to a fully martensitic microstructure with minor remnants of the cellular substructures associated with the solidification conditions in ASHM. DA resulted in some reverted austenite and partial dissolution of the cellular morphologies into shorter fragments. Despite the contrasting microstructures, the tensile strength and the macro- and micro-hardness were comparable between STA and DA conditions. By contrast, the potential for improving the ductility was higher with the DA heat treatment. This is attributed to the higher reverted austenite content in the samples treated by DA, i.e., up to a maximum of 13.4% compared to less than 3.0% in the STA samples. For the DA sample with the highest reverted austenite content of 13.4%, the highest local and global fracture strain values of 30.1 and 5.9 ± 0.6% were measured, while the respective values were 23.4 and 4.4 ± 0.1% for the corresponding STA sample. This work suggests that DA of 300 MS produced by ASHM is sufficient to achieve comparable hardness and tensile strength to STA, whilst maintaining reasonable ductility. Avoiding the solution treatment cycle, with its appreciably higher temperatures, could benefit the dimensional stability and surface quality that are important for ASHM of 300 MS parts.

Adaptations for gas exchange enabled the elongation of lepidopteran proboscises.

The extensive biodiversification of butterflies and moths (Lepidoptera) is partly attributed to their unique mouthparts (proboscis [Pr]) that can span in length from less than 1 mm to over 280 mm in Darwin's sphinx moths. Lepidoptera, similar to other insects, are believed to inhale and exhale respiratory gases only through valve-like spiracles on their thorax and abdomen, making gas exchange through the narrow tracheae (Tr) challenging for the elongated Pr. How Lepidoptera overcome distance effects for gas transport to the Pr is an open question that is important to understanding how the Pr elongated over evolutionary time. Here, we show with scanning electron microscopy and X-ray imaging that distance effects on gas exchange are overcome by previously unreported micropores on the Pr surface and by superhydrophobic Tr that prevent water loss and entry. We find that the density of micropores decreases monotonically along the Pr length with the maxima proportional to the Pr length and that micropore diameters produce a Knudsen number at the boundary between the slip and transition flow regimes. By numerical estimation, we further show that the respiratory gas exchange for the Pr predominantly occurs via diffusion through the micropores. These adaptations are key innovations vital to Pr elongation, which likely facilitated lepidopteran biodiversification and the radiation of angiosperms by coevolutionary processes.

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.