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Natural zeolite is commonly used as an adsorbent for road dust suppression due to its excellent moisture absorption properties. However, during the formation process, natural zeolite tends to accumulate some zeolite water, organic impurities, and metal cations that occupy the pore channels and cavities, thereby blocking the passage of water molecules and hindering their adsorption. This study aims to improve the weak moisture absorption rate and capacity of dust suppression asphalt mixtures caused by clogged pores and impurities in natural zeolite. To achieve this different concentrations of salt solutions (NH4Cl, NaCl, MgCl2, and CaCl2) are used as modifiers for the treatment of natural zeolite. Scanning electron microscopy and Fourier transform infrared spectroscopy are used to study the interface and functional group changes between the modified zeolite substrate and asphalt mixture. The nitrogen adsorption/desorption curves of asphalt mixtures with different dosages were obtained using a nitrogen adsorption instrument. Based on this, parameters such as the specific surface area and adsorption pore volume of natural zeolite and modified zeolite asphalt mixtures were calculated using the BET and BJH methods. A macroscopic dust suppression test was further conducted to evaluate the dust suppression effect of the modified zeolite asphalt mixture on PM10. The results show that the moisture absorption rate and capacity of the modified zeolite are significantly improved. 20wt.%CaCl2 modification performs the best, and the moisture absorption capacity of the modified zeolite can reach up 10 times that of natural zeolite. Compared to the natural zeolite asphalt mixture, the specific surface area of the modified zeolite asphalt mixture is increased by 16.52%, and the adsorption pore volume is increased by 44.9%. The addition of modified zeolite powder significantly improves the dust suppression performance of the asphalt mixture. When the dosage of modified zeolite powder reaches 80%, the dust suppression effect reaches its peak, with an improvement of 16.34%. [ABSTRACT FROM AUTHOR]

[Display omitted] Electrochemical synthesis of ammonia is a green and sustainable way for nitrogen fixation, but the development of efficient electrocatalysts still faces challenges. The modulation of electronic structure through interface engineering and vacancy engineering is a new approach to enhance the performance of electrocatalysts. In this work, a phosphorus-doped core–shell heterojunction P-Sb 2 S 3 /MoS 2 was designed and synthesized by combining antimony, which is inert to H+ adsorption, with molybdenum, which has good affinity and reducibility with nitrogen. The synthesis involved both interfacial engineering and vacancy engineering strategies. DFT calculations demonstrate that the formation of Sb 2 S 3 /MoS 2 heterojunction enhances the creation of a built-in electric field, thereby expediting electron flow. Additionally, phosphorus doping induced the formation of abundant sulfur vacancies, significantly enhancing nitrogen adsorption performance in this material. As a result, our designed structure exhibited excellent NRR performance with an ammonia production rate of 41.22 μg·h−1·mg−1 cat and a Faraday efficiency of 15.70 %. The unique structural of this catalyst contribute to a more optimal balance between the rate of ammonia production and the Faraday efficiency. The successful preparation of the highly efficient P-Sb 2 S 3 /MoS 2 heterojunctions provides a new strategy for catalyst design in electrocatalytic nitrogen reduction. [ABSTRACT FROM AUTHOR]

A large surface area, wide band gap, and unique bonding property between Zn and O atoms make the hexagonal ZnO monolayer attractive as a gas sensor. In the present work, the adsorption and evolution of nitrogen (N2) molecules over a ZnO monolayer have been studied using two different theoretical methods: van der Waals density functional theory (vdW-DFT) and kinetic Monte-Carlo (kMC) simulation. The adsorption and diffusion (hopping over the surface) energy of a N2 gas molecule has been calculated considering the different sites over the ZnO substrate using the revPBE-vdW functional. Bader charge, electron localization function analysis, density of states and band structure plotting have been used to understand the adsorption mechanism. Lateral repulsive interaction between two N2 molecules limits the maximum packing number of gas molecules within one hexagonal ring. The output of the vdW-DFT calculation has been fed to the kMC code to predict the rate of adsorption, desorption, and diffusion, along with the overall surface coverage at different temperatures and pressures. Finally, the change in the N2 adsorption energy has been predicted with the increase of the ZnO layer number. [ABSTRACT FROM AUTHOR]

Abstract In this study, we explore the mechanical treatment of two metal–organic frameworks (MOFs), HKUST-1 and MOF-76, applying various milling methods to assess their impact on stability, porosity, and CO2 adsorption capacity. The effects of different mechanical grinding techniques, such as high-energy ball milling and hand grinding, on these MOFs were compared. The impact of milling time, milling speed and ball size during high-energy ball milling was assessed via the Design of Experiments methodology, namely using a 33 Taguchi orthogonal array. The results highlight a marked improvement in CO2 adsorption capacity for HKUST-1 through hand milling, increasing from an initial 25.70 wt.% (5.84 mmol g-1) to 41.37 wt.% (9.40 mmol g-1), marking a significant 38% increase. In contrast, high-energy ball milling seems to worsen this property, diminishing the CO2 adsorption abilities of the materials. Notably, MOF-76 shows resistance to hand grinding, closely resembling the original sample’s performance. Hand grinding also proved to be well reproducible. These findings clarify the complex effects of mechanical milling on MOF materials, emphasising the necessity of choosing the proper processing techniques to enhance their stability, texture, and performance in CO2 capture and storage applications.

Copyright of Fly Ash Comprehensive Utilization is the property of Hebei Fly Ash Comprehensive Utilization Magazine Co., Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Natural zeolite is commonly used as an adsorbent for road dust suppression due to its excellent moisture absorption properties. However, during the formation process, natural zeolite tends to accumulate some zeolite water, organic impurities, and metal cations that occupy the pore channels and cavities, thereby blocking the passage of water molecules and hindering their adsorption. This study aims to improve the weak moisture absorption rate and capacity of dust suppression asphalt mixtures caused by clogged pores and impurities in natural zeolite. To achieve this different concentrations of salt solutions (NH4Cl, NaCl, MgCl2, and CaCl2) are used as modifiers for the treatment of natural zeolite. Scanning electron microscopy and Fourier transform infrared spectroscopy are used to study the interface and functional group changes between the modified zeolite substrate and asphalt mixture. The nitrogen adsorption/desorption curves of asphalt mixtures with different dosages were obtained using a nitrogen adsorption instrument. Based on this, parameters such as the specific surface area and adsorption pore volume of natural zeolite and modified zeolite asphalt mixtures were calculated using the BET and BJH methods. A macroscopic dust suppression test was further conducted to evaluate the dust suppression effect of the modified zeolite asphalt mixture on PM10. The results show that the moisture absorption rate and capacity of the modified zeolite are significantly improved. 20wt.%CaCl2 modification performs the best, and the moisture absorption capacity of the modified zeolite can reach up 10 times that of natural zeolite. Compared to the natural zeolite asphalt mixture, the specific surface area of the modified zeolite asphalt mixture is increased by 16.52%, and the adsorption pore volume is increased by 44.9%. The addition of modified zeolite powder significantly improves the dust suppression performance of the asphalt mixture. When the dosage of modified zeolite powder reaches 80%, the dust suppression effect reaches its peak, with an improvement of 16.34%.

In order to study the influence of low temperature liquid nitrogen immersion treatment on the pore structure and fractal characteristics of middle grade coal in Huainan Mining Area, coal samples were treated with different liquid nitrogen immersion time, and the pore structure of coal was measured by mercury injection and liquid nitrogen adsorption method. The fractal theory was combined to analyze the development law and scale characteristics of coal pores under different immersion time from multiple angles. The results show that with the increase of liquid nitrogen immersion time, the total pore volume of coal increases from 198.089×10−3 cm3/g to 371.553×10−3 cm3/g, while the total specific surface area decreases from 4.984 m2/g to 4.496 m2/g, and the effect is significant. The adsorption pore decreases, the seepage pore increases, and the pore connectivity of the adsorption pore increases to form a larger level of pore, which gradually changes to the seepage pore. There was a negative linear correlation between D1 (fractal dimension of seepage pore) and D2 (fractal dimension of adsorption pore) and the immersion time of liquid nitrogen, and the influence of liquid nitrogen immersion on D1 was more significant than that of D2. D1 and D2 decreased gradually with the increase of liquid nitrogen immersion time, indicating that the structural complexity of internal pores decreased with the increase of liquid nitrogen immersion time, and the porosity and permeability of coal increased. Dc (comprehensive fractal dimension) decreases with the increase of average pore diameter and total pore volume of coal body, and increases with the increase of total specific surface area. With the increase of liquid nitrogen immersion time, the comprehensive fractal dimension of coal body decreases, the adsorption capacity of coal body is weakened, and the seepage capacity is enhanced, which is helpful to improve the coal-bed methane extraction effect of low permeability coal seam in Huainan Mining Area.

Nitrogen-adsorbing carbon nanotubes have received considerable attention in the field of materials science due to their unique properties and potential applications. In particular, nitrogen-adsorbed double-walled carbon nanotubes (DWNTs) can exhibit a wide range of tunable electronic and optoelectronic properties. In this study, the effect of different temperatures (i.e., 300, 600, and 900 K) of DWNT on nitrogen adsorption is investigated through molecular dynamics simulations using the ReaxFF potential. The simulation results show a good nitrogen storage capacity of DWNT, particularly at 600 K, reaching a maximum gravimetric density of 12.4 wt%. This study contributes to a better understanding of the mechanisms governing nitrogen adsorption onto DWNTs at different temperatures.

[Display omitted] The photocatalytic performance of ceria-based materials can be tuned by adjusting the surface structures with decorating the transition-metal, which are considered as the important active sites. Herein, cuprous oxide-metallic copper composite - doped ceria nanorods were assembled through a simple hydrothermal reduction method. The photocatalytic ammonia synthesis rates exhibit an inverted "V-shaped" trend with increasing Cu0/Cu x O mole ratio. The best ammonia production rate, approximately 900 or 521 µmol·g cal −1·h−1 under full-spectra or visible light, can be achieved when the Cu0/Cu x O ratio is approximately 0.16, and this value is 8 times greater than that of the original sample. The absorption edge of the as-prepared samples shifted towards visible wavelengths, and they also had appropriate ammonia synthesis levels. This research provides a strategy for designing noble metal-free photocatalysts through introducing the metal/metallic oxide composites to the catalysts. [ABSTRACT FROM AUTHOR]

This study investigated the influence of movable oil on the pore structure of various shale types, analyzing 19 shale samples from Well X in the Mahu Sag of the Junggar Basin. Initially, X-ray diffraction (XRD) analysis classified the shale samples. Subsequently, the geochemical properties and pore structures of the samples, both pre and post oil Soxhlet extraction, were comparatively analyzed through Total Organic Carbon (TOC) content measurement, Rock-Eval pyrolysis, and nitrogen adsorption experiments. Additionally, fractal theory quantitatively described the impact of movable oil on the pore structure of different shale types. Results indicated higher movable oil content in siliceous shale compared to calcareous shale. Oil extraction led to a significant increase in specific surface area and pore volume in all samples, particularly in siliceous shale. Calcareous shale predominantly displays H2–H3 type hysteresis loops, indicating a uniform pore structure with ink-bottle-shaped pores. Conversely, siliceous shale exhibited diverse hysteresis loops, reflecting its complex pore structure. The fractal dimension in calcareous shale correlated primarily with pore structure, exhibiting no significant correlation with TOC content before or after oil extraction. Conversely, the fractal dimension changes in siliceous shale samples do not have a clear correlation with either TOC content or pore structure, suggesting variations may result from both TOC and pore structure. [ABSTRACT FROM AUTHOR]

In this paper, we report a method for synthesizing high-yield graphene-containing biocarbon from burlap waste through a simple two-step carbonization process. The first step involves feedstock carbonization at 600 °C, followed by ball milling and then graphitization at 1200 °C using KOH. A comparative analysis between the obtained bio-graphene and commercial graphene revealed superior graphene properties of the burlap-based graphene. Notably, this bio-based graphene exhibited exceptional characteristics such as a very high BET surface area in the range of 1021 m²/g, low defect-to-graphene ratio of 0.12 in the Raman spectra, and an overall yield of 19% wt. These findings highlight the potential of burlap waste as a sustainable precursor for high-quality graphene synthesis and its potential for various applications.

Abstract Tight sandstone has strong pore heterogeneity and complex pore structure, and the pore structure of tight sandstone varies with different permeability. To study the differences in the pore structure of tight sandstone with different permeability, this study investigated the tight sandstone of the He 8 Member in the Gaoqiao area of the Ordos Basin. Factors influencing pore formation are analyzed through experiments utilizing methods, such as distinguishing casting thin sections, scanning electron microscopy, high‐pressure mercury intrusion, and low‐temperature nitrogen adsorption. The results indicate that in this area, the pores of the tight sandstone are primarily dissolution and intercrystalline pores, with occasional intergranular pores and microcracks. Type Ⅱ samples (permeability > 0.2 × 10−3 μm2) are primarily composed of dissolution and intercrystalline pores, with a few visible intergranular and microcracks. In contrast, Type Ⅰ samples (permeability

Copyright of Industrial Minerals & Processing / Huagong Kuangwu yu Jiagong is the property of Industrial Minerals & Processing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study designed integrated constructed wetland–microbial fuel cell (CW–MFC) systems using activated carbon (AC) as both CW substrates and MFC anodes and investigated the structure-activity relationship of six kinds of commercial columnar AC, as well as the organics and nitrogen removal, microbial activity and diversity of CW–MFCs. Results showed that the nitrogen adsorption by AC tended to be a linear process in which physical adsorption played a leading role and micropores made great contributions. A higher specific surface area, developed mesopores, and oxygen functionalities were conducive to the capacitance properties of AC, while a higher specific surface area and developed micropores were conducive to reduce material resistance and improve ion permeability. Coconut-shell-based AC had both excellent nitrogen adsorption capacity and electrochemical properties, making it ideal as both CW substrates and MFC anodes for CW–MFCs. The electricity generation, coulombic efficiency, internal resistance, and organics and nitrogen removal of CW–MFCs were positively correlated with the total depth of AC anodes. The total depth of AC anodes can be determined based on the influent organics/nitrogen loadings and organics/nitrogen removal load of AC, and a relatively smaller depth of a single AC anode (5 cm) was recommended. The MFC effectively improved the enzymatic activity (by 10.33% dehydrogenase, 8.72% catalase, and 7.35% ammonia monooxygenase), nitrification/denitrification intensity (by 9.53%/6.68%), and microbial diversity (by 1.64–4.07%) of AC (MFC anodes) in CW–MFCs, while the depth of a single AC anode barely influenced the microbial activity and diversity. MFCs increased COD and NH3-N removal in CW–MFCs by 11.60% and 3.4%, respectively. The increased total adsorption capacity of AC with the increase of its total depth narrowed the difference in COD removal resulting from the promotion of MFCs on organics degradation. MFCs increased TN removal in CW–MFCs by 5.29% through promoting denitrification in cathodes and enhancing NH3-N assimilation in anodes. The phyla of EAB (Proteobacteria, Bacteroidetes, Firmicutes, and Acidobacteria) and genera of EAB (Citrobacter, Geobacter, and Pseudomonas) accounted for 85–86% and 15.58–16.64% of the microbial community on AC anodes in CW–MFCs, respectively. [ABSTRACT FROM AUTHOR]

In this paper, anthracite in Shanxi region is taken as a research object, and the pore structure of coal under different freeze-thaw times is characterized and analyzed by scanning electron microscope and nitrogen adsorption experiment. The SEM experimental results show that the micron-scale cracks on the surface of anthracite gradually connect after freeze-thaw, and the secondary crack channels are formed around the pores and air holes, so that the pores also begin to connect. Further, the quantitative information of the picture was extracted, and it was found that the surface porosity and fractal dimension of the coal sample changed significantly after three freeze-thaw cycles, which increased by 163.3% and 15.9% respectively, and increased with the increase of freeze-thaw cycles. The results of low-temperature nitrogen adsorption experiments show that the coal samples after freeze-thaw are mainly crack, and the pore structure changes from simple to complex. In addition, the maximum nitrogen adsorption capacity, specific surface area and pore volume increased by 125.7%, 69.3% and 72.6%, respectively. With the increase of freeze-thaw times, the growth rates of maximum nitrogen adsorption capacity, specific surface area and pore volume are significantly different. The results of joint characterization show that the number of pores and cracks increases to different degrees after freezing and thawing. Comparing the increase in the degree of fracturing (163.3%) with the increase in the total pore volume (30.68%), we find that the degree of change of the crack after thawing is higher than that of the pore. In this paper, the damage effect of coal samples after freezing and thawing with liquid nitrogen is investigated from an experimental point of view, which accelerates the great leap of cyclic cryogenic fracturing technology from basic theory to technical practice. [ABSTRACT FROM AUTHOR]

Tight sandstone has strong pore heterogeneity and complex pore structure, and the pore structure of tight sandstone varies with different permeability. To study the differences in the pore structure of tight sandstone with different permeability, this study investigated the tight sandstone of the He 8 Member in the Gaoqiao area of the Ordos Basin. Factors influencing pore formation are analyzed through experiments utilizing methods, such as distinguishing casting thin sections, scanning electron microscopy, high‐pressure mercury intrusion, and low‐temperature nitrogen adsorption. The results indicate that in this area, the pores of the tight sandstone are primarily dissolution and intercrystalline pores, with occasional intergranular pores and microcracks. Type Ⅱ samples (permeability > 0.2 × 10−3 μm2) are primarily composed of dissolution and intercrystalline pores, with a few visible intergranular and microcracks. In contrast, Type Ⅰ samples (permeability < 0.2 × 10−3 μm2) mainly consist of micropores and intercrystalline pores, where microcracks are observed locally. Pore size research demonstrates that Type Ⅰ samples have pore size under 1000 nm, with peaks primarily at 4–5 nm. There are also peaks between 10–1000 nm, but without a consistent pattern. For Type Ⅱ samples with sizes smaller than 1000 nm, pore distribution is evident. Peak values when the pore size exceeds 1000 nm. Type Ⅰ samples have fewer micron‐level pores, while Type Ⅱ samples are primarily dissolution pores. The nanopores of Type Ⅰ samples consist of flat pores with good connectivity, whereas those of Type Ⅱ samples are mainly blind pores with poor connectivity. Type Ⅰ samples have larger pore fractal dimensions, more intricate pore morphology, and rougher and irregular pore throat surfaces compared to Type II samples. Hence, the sedimentary environment, diagenesis, and mineral composition affect the pore distribution in tight sandstone. The research findings highlight the variations in the pore structure of tight sandstone with varying permeability, providing crucial guidance for classifying and assessing pore structure in tight sandstone reservoirs. [ABSTRACT FROM AUTHOR]

Nitrogen-adsorbing carbon nanotubes have received considerable attention in the field of materials science due to their unique properties and potential applications. In particular, nitrogen-adsorbed double-walled carbon nanotubes (DWNTs) can exhibit a wide range of tunable electronic and optoelectronic properties. In this study, the effect of different temperatures (i.e., 300, 600, and 900 K) of DWNT on nitrogen adsorption is investigated through molecular dynamics simulations using the ReaxFF potential. The simulation results show a good nitrogen storage capacity of DWNT, particularly at 600 K, reaching a maximum gravimetric density of 12.4 wt%. This study contributes to a better understanding of the mechanisms governing nitrogen adsorption onto DWNTs at different temperatures. [ABSTRACT FROM AUTHOR]

Alkali pollution can affect the physical and mechanical properties of lateritic soil to different degrees depending on soil type, alkali concentration, and interaction time. This study aimed to investigate the effect of alkali concentration on mechanical and microscopic characteristics of undisturbed lateritic soil and its influence mechanism. The soil samples were contaminated at different concentrations of sodium hydroxide solution (pH = 8.8, 9.4, 11.4, 12.4, 13.4) for 24 h. The particle and pore distribution, mineral composition, morphological characteristics, and mechanical strength of alkali-contaminated soil were measured. It was found that the products of kaolinite minerals dissolved by alkali would undergo polycondensation to form aluminosilicate gels. These gels filled the pores and bound the soil particles, increasing the compressive strength of the soil. In the strong alkaline environment (pH = 12.4 and 13.4), the formation of gels was inhibited by high concentration of OH− and the collapse of soil skeleton caused by the violent dissolution of kaolinite was the cause for the decrease in unconfined uniaxial compressive strength. [ABSTRACT FROM AUTHOR]

Abstract During the in-situ exploitation of oil shale, the evolution of pore structure will affect the heat transfer medium and the transport capacity of products. In this study, using the oil shale from Jimsar region of Xinjiang, in combination with the low-temperature nitrogen adsorption experiment (LNTA) and high-pressure mercury injection experiment (MIP), the effect of temperature on evolution law of its pores during pyrolysis were analyzed according to the LNTA and MIP joint characterization results. The results show as follows: the change curve of oil shale porosity with pyrolysis final temperature in Xinjiang shows an “S” shape. The pore volume increases slightly before 300 °C, and it shows an increasing trend in the subsequent temperature range, with the mesopore volume change being the most noticeable. However, the increase slows down after 600 °C. The evolution of full-scale pores in the pyrolysis process of oil shale is reflected by the joint characterization of LNTA and MIP, which indicates that the temperature has a controlling effect on the evolution of pore, and provides basic theoretical support for how to improve the oil recovery rate of exploitation of oil shale.

Reducing the environmental problems caused by nitrogen loss and nitrogen pollution is of great significance. The addition of biochar to soil is a new method for increasing nitrogen interception due to the special structural and physicochemical properties of biochar. The optimal modified biochar was screened out after acid–base modification and batch adsorption test in this paper. And then the effects of different soil and biochar mixing methods on soil physicochemical properties and nitrogen adsorption and retention were explored through soil column leaching test. The results showed that the biochar with a pyrolysis temperature of 700 °C had the best adsorption effect on nitrogen after being modified by 0.1 mol/L HCI, and the adsorption capacity of nitrate nitrogen reached 121.46 mg/g. The adsorption process of ammonia nitrogen and nitrate nitrogen conformed to the Langmuir model and was mainly homogeneous monolayer. After mixing the selected modified biochar with black soil, the pH increased by 4.77%, the content of ammonia nitrogen increased by 4.89%, and the nitrate content increased by 16.62%. In this study, the adsorption effect of biochar on nitrogen in black soil was discussed, so as to explore the optimal use of biochar in soil, which provided some reference basis for the relevant research. [ABSTRACT FROM AUTHOR]

The nanocomposite of resorcinol–formaldehyde xerogel (RF-xerogel) and carbon nanotubes after carbonization at 800°С was obtained in the form of composite carbon nanopaper (CCNP) with a thickness of 100–300 microns, a density from 0.1 to 0.5 g/cm2 and an electronic conductivity of more than 10 S/cm. According to the low temperature nitrogen adsorption data, the microporous structure of the nanopaper is formed by carbonized RF-xerogel, and the mesoporous structure is formed by the nanotube framework. The specific surface area of the nanopaper calculated by the method of nonlocal density function theory (NLDFT) exceeds 600 m2/g. The main contribution to the specific surface area of CCNP is made by pores with a width of ~0.7 nm, therefore, electrodes for a supercapacitor made of such paper are quite effective only in aqueous solutions of H2SO4 and KOH with small sizes of solvated ions. A technique for nanopaper activation with potassium hydroxide has been developed for the use of CCNP with organic electrolytes. The maximum specific surface area (NLDFT method) of activated CCNP reaches 1182 m2/g with a loss of carbon xerogel mass of ~25%. At the same time, the pore surface area of more than 1 nm width increases from 350 m2/g in CCNP to 685 m2/g in activated CCNP. Nanopaper has mechanical strength, pretty cheap and convenient for use in supercapacitors. [ABSTRACT FROM AUTHOR]

This study investigated the influence of movable oil on the pore structure of various shale types, analyzing 19 shale samples from Well X in the Mahu Sag of the Junggar Basin. Initially, X-ray diffraction (XRD) analysis classified the shale samples. Subsequently, the geochemical properties and pore structures of the samples, both pre and post oil Soxhlet extraction, were comparatively analyzed through Total Organic Carbon (TOC) content measurement, Rock-Eval pyrolysis, and nitrogen adsorption experiments. Additionally, fractal theory quantitatively described the impact of movable oil on the pore structure of different shale types. Results indicated higher movable oil content in siliceous shale compared to calcareous shale. Oil extraction led to a significant increase in specific surface area and pore volume in all samples, particularly in siliceous shale. Calcareous shale predominantly displays H2–H3 type hysteresis loops, indicating a uniform pore structure with ink-bottle-shaped pores. Conversely, siliceous shale exhibited diverse hysteresis loops, reflecting its complex pore structure. The fractal dimension in calcareous shale correlated primarily with pore structure, exhibiting no significant correlation with TOC content before or after oil extraction. Conversely, the fractal dimension changes in siliceous shale samples do not have a clear correlation with either TOC content or pore structure, suggesting variations may result from both TOC and pore structure.

Copyright of Iraqi Journal of Chemical & Petroleum Engineering is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Engineering Geology / Gongcheng Dizhi Xuebao is the property of Journal of Engineering Geology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study designed integrated constructed wetland–microbial fuel cell (CW–MFC) systems using activated carbon (AC) as both CW substrates and MFC anodes and investigated the structure-activity relationship of six kinds of commercial columnar AC, as well as the organics and nitrogen removal, microbial activity and diversity of CW–MFCs. Results showed that the nitrogen adsorption by AC tended to be a linear process in which physical adsorption played a leading role and micropores made great contributions. A higher specific surface area, developed mesopores, and oxygen functionalities were conducive to the capacitance properties of AC, while a higher specific surface area and developed micropores were conducive to reduce material resistance and improve ion permeability. Coconut-shell-based AC had both excellent nitrogen adsorption capacity and electrochemical properties, making it ideal as both CW substrates and MFC anodes for CW–MFCs. The electricity generation, coulombic efficiency, internal resistance, and organics and nitrogen removal of CW–MFCs were positively correlated with the total depth of AC anodes. The total depth of AC anodes can be determined based on the influent organics/nitrogen loadings and organics/nitrogen removal load of AC, and a relatively smaller depth of a single AC anode (5 cm) was recommended. The MFC effectively improved the enzymatic activity (by 10.33% dehydrogenase, 8.72% catalase, and 7.35% ammonia monooxygenase), nitrification/denitrification intensity (by 9.53%/6.68%), and microbial diversity (by 1.64–4.07%) of AC (MFC anodes) in CW–MFCs, while the depth of a single AC anode barely influenced the microbial activity and diversity. MFCs increased COD and NH3-N removal in CW–MFCs by 11.60% and 3.4%, respectively. The increased total adsorption capacity of AC with the increase of its total depth narrowed the difference in COD removal resulting from the promotion of MFCs on organics degradation. MFCs increased TN removal in CW–MFCs by 5.29% through promoting denitrification in cathodes and enhancing NH3-N assimilation in anodes. The phyla of EAB (Proteobacteria, Bacteroidetes, Firmicutes, and Acidobacteria) and genera of EAB (Citrobacter, Geobacter, and Pseudomonas) accounted for 85–86% and 15.58–16.64% of the microbial community on AC anodes in CW–MFCs, respectively.

BACKGROUND Porosity is a key parameter for exploration and evaluation of shale gas reservoirs. Rapid and accurate determination of shale porosity is crucial for reserve calculation. At present, there are helium gas method, liquid saturation method and image analysis method applied to shale porosity determination, but the comparison between methods and laboratories is lacking. OBJECTIVES To evaluate the applicability of different methods for determining shale porosity. METHODS The characteristics of 69 shale samples from the Longmaxi Formation were studied by analyzing and testing techniques such as X-ray diffraction, argon ion polishing-scanning electron microscopy, and mercury injection-nitrogen adsorption method. Comparison experiments for porosity measurement were conducted among helium method, liquid saturation method and image analysis method. RESULTS The Longmaxi Formation shale had high clay content, many organic pores, small pore throats, and poor seepage capacity, which made it difficult for foreign liquids and gases to quickly enter the pores, which required high resolution of core image data. The liquid saturation method (alcohol method) used 20MPa pressure to saturate the sample for 24 hours, resulting in core damage, and the measured porosity deviated from the true value. The image analysis method ignored the micropores (pore size < 2nm) and mesopores (pore size < 50nm) in the mineral matrix and other factors, making the porosity measurement result unreliable. The porosity measurement result of the helium method was closely related to the drying temperature and stabilization time. The higher the temperature, the larger the measured porosity, and if the stabilization time is too short, the porosity result will be smaller than the real values. CONCLUSIONS After drying the core at 60℃ for more than 24 hours to a constant weight, by setting a reasonable stabilization time, accurate porosity results can be obtained by the helium method. Properly increasing the injection pressure helps to speed up the experimentation rate.

The influence of coalification on coal structure evolution in middle ranked coals is significant for physical assessment of coalbed methane (CBM) reservoirs, which provides insights on the intrinsic connection between coalification jump and pore heterogeneity. A total of 26 middle-ranked coals were samples covering Liupanshui Coalfield in Guizhou Province, Anhe Coalfield in Henan Province, Huaibei Coalfield in Anhui Province, Sanjiang Basin in Heilongjiang Province, Ordos Basin in Shaanxi Province and Qinshui Basin in Shanxi Province. Based on a series of experiments including vitrinite reflectance, coal maceral identification, nitrogen adsorption and the pore fractal method, the inner link between physical property parameters of coal reservoirs and coal rank was revealed. The results show that the coal maceral in middle rank coals is dominated by vitrinite and inertinite and two types of adsorption pores are divided according to the nitrogen adsorption/desorption curves along with pore size distribution. The specific surface area is positively correlated with total pore volume, micropore volume and negatively correlated with averaged pore size and transitional pore volume. The coal samples with low average pore sizes have relatively high total pore volume, specific surface area and micropore volume per unit nm. With the increase of coal rank, the fluctuating points of micropore and transitional pore volume correspond to 1.16%–1.19%, 1.41%–1.43% and 1.86%–1.91% of Ro, max, respectively. The boundary of Ro, max corresponding to the second coalification jump can be more specifically defined as 1.16%–1.19% from the established nominal range of 1.1%–1.3%. The pore fractal dimension DNA1 and DNA2 increase with increasing specific surface area. Furthermore, the DNA2 has a negative correlation with micropore volume and averaged pore size, indicating that the coal with smaller average pore diameter and lower micropore content has a more complex pore structure.

Tetradecahydrophenazine (14HP) is a nitrogen-containing heterocycle compound with a high content of hydrogen that can be released during its dehydrogenation to phenazine (P). The high stability of the 14HP/P pair and relatively low dehydrogenation temperature make 14HP a promising organic hydrogen carrier. This manuscript is devoted to the investigation of hydrogen production by 14HP dehydrogenation over Pd supported on a series of magnesium-aluminum oxides prepared by the aerogel method. This technique made it possible to synthesize catalyst supports characterized by a high surface area and high concentration of surface active sites where active transition metals could be stabilized in a finely dispersed state. The synthesized aerogels had high specific surface areas and pore volumes. A surface area as high as 600 m2/g after calcination at 500 °C was observed for the mixed aerogel with an Mg:Al ratio of 1:4. An increase in the concentration of acidic electron-acceptor sites determined by EPR on the surface of the mixed magnesium-aluminum oxide supports with a high surface area prepared by the aerogel method was found to result in higher hydrogen production due to the faster dehydrogenation of sterically hindered nitrogen-containing tetradecahydrophenazine heterocycles. [ABSTRACT FROM AUTHOR]

At present, there are few studies on the fine quantitative characterization of the physical properties and pore structures of the Lower Silurian Longmaxi shale in the southern Sichuan Basin. In this paper, taking the shale of the Longmaxi Formation in the southern Sichuan area as an example, the nitrogen adsorption, geochemical tests and mineral testing experiments were used to systematically study the mineral composition, geochemical characteristics, types and morphology of pores, and fractal characteristics of the shale. The research results show that the internal structure of the Longmaxi Formation shale is compact, the internal components are mainly muddy components, and its lithofacies are mainly clay shale and calcareous clay shale. The TOC content of shale is generally between 0.48% and 6.2%, the average TOC content is 2.55%, and the thickness of high-quality shale is between 40 and 60 m. The Longmaxi Formation shale has experienced deep burial and strong hydrocarbon generation. Moreover, the organic matter pores in the Longmaxi Formation mainly develop biological pores, asphalt pellet pores, mold pores and gas pores. The Longmaxi Formation is in the high-over-mature stage (maturity greater than 2%), and a large number of pores are often developed in interstitial organic matter and inter-wrapped organic matter. The lowtemperature nitrogen adsorption-desorption curves show that the hysteresis loops of the Longmaxi shale are relatively small, and the pores have parallel plate-like form. In addition, the total organic carbon content of the shale pores in the study area has a good positive correlation with the fractal dimension, and the micropore surface area also has a good positive correlation with the fractal dimension. The fractal dimension is positively correlated with the total specific surface area. That is, the smaller the average pore size of shale pores, the larger the total specific surface area, the stronger the heterogeneity, and the larger the fractal dimension. This study can provide a basis for the efficient exploration and development of shale gas sweet spots. [ABSTRACT FROM AUTHOR]

To investigate the changes in the pore structure of earlywood and latewood (EW and LW) in larch during the heat treatment process, this study applied nitrogen adsorption and mercury intrusion porosimetry (MIP) to measure wood pore characteristics. Wood samples were heat treated within a vacuum atmosphere at temperatures between 180 and 220 °C for 6 h. Analysis conducted on nitrogen adsorption isotherms indicated that the micropores and mesopores in the cell walls were present in both untreated and heat-treated EW and LW, and that the mesopores appeared as slit-shaped pores. More pores were detected in EW compared to LW, and these primarily absorbed in the range of 1.5–4 nm. Compared with the untreated wood, the total pore volume of treated wood decreased with increasing temperatures, with decreased pore volumes at 220 °C of 63 and 42% for EW and LW, respectively. The MIP results showed a greater porosity of EW compared to LW. Compared with the untreated wood, the porosity of heat-treated EW and LW first increased with increasing temperature, and then decreased at 220 °C. For treatment temperatures lower than 200 °C, heat treatment increased the proportion of macropores with pore sizes in the ranges of 100–1000 nm and 10,000–40,000 nm. [ABSTRACT FROM AUTHOR]

Fluoride ions are toxic, and F− in groundwater for drinking should be sufficiently reduced to be less than the regulated concentration. In this study, cellulose nanofibril-containing iron oxyhydroxide (FeOOH) powders were synthesized, and their F− adsorption behaviors were studied under various conditions. 2,2,6,6-Tetramethylpiperidine-1-oxyl (TEMPO)-oxidized cellulose nanofibrils (CNFs) were added to 0.1 M FeCl3, and 1 M NaOH was added to the FeCl3/TEMPO–CNF mixture to prepare FeOOH precipitates at various FeOOH/TEMPO–CNF mass ratios. When TEMPO–CNFs were present in the FeCl3 solution, the FeOOH/TEMPO–CNF precipitates were quantitatively obtained by straightforward filtration with filter paper; enabled by the larger size (> 300 µm) of the FeOOH/TEMPO–CNF precipitates than the FeOOH precipitates (< 100 µm) prepared without TEMPO–CNFs. The oven-dried FeOOH/TEMPO–CNF powder (87/13 by mass) showed the highest F− adsorption ratio in water compared with the synthesized FeOOH/TEMPO–CNF powders with FeOOH/TEMPO–CNF mass ratios of 100/0, 79/21, and 73/27. The F− adsorption ratios of the FeOOH/TEMPO–CNF powders were stable over the pH range 4‒10. Scanning electron microscopy and energy-dispersive spectroscopy analyses of the powder surfaces before and after F− adsorption indicate that the F− in water adsorbed onto the FeOOH/TEMPO–CNF powder (87/13 by mass) and partially replaced the Cl− that was originally present in the powder. Thus, the FeOOH/TEMPO–CNF powder prepared in this study can be used as efficient, cost-effective F− adsorbents for drinking water and industrially polluted wastewater. [ABSTRACT FROM AUTHOR]

The pore characteristics of coal reservoirs play a very important role in the migration of coalbed methane reservoirs, and its heterogeneity has been studied by a large number of scholars. However, there are few studies on lignite reservoirs. In this paper, three sets of lignite reservoirs in the Jiergalangtu depression are taken as the research object. The scanning electron microscope (SEM) images are converted from time-domain signals to frequency-domain signals through Fourier transformation, which quantitatively characterizes the heterogeneity of coal reservoirs. The variance of the value indicates that the three sets of coal seams NO.4Var

In order to more comprehensively characterize the pore structure characteristics of Qianjiang Formation shale oil reservoir in Qianjiang Sag, several shale samples from Well A and Well B with different distances from the source were systematically selected for analyzing and testing, and the pore structure characteristics of shale were comprehensively analyzed by field emission scanning electron microscope, low temperature nitrogen adsorption and mercury intrusion capillary pressure experiment; Making a further study by comparing the field emission scanning electron microscope images, low-temperature nitrogen adsorption and mercury intrusion capillary pressure experimental data on the occurrence space characteristics of retained hydrocarbons in shale; The pore size distribution of connected pores in shale is discussed through the secondary mercury injection experiments on typical shale samples.This study shows that the pore size of Qianjiang Formation shale oil reservoir in Qianjiang Sag is nanometer micron scale, and 2-180 nm clay mineral interlayer pore and dolomite intergranular pore are the two main pore types in this area; The retained hydrocarbon in Well A shale mainly exists in 2-20 nm clay mineral interlayer pores, the content of retained hydrocarbon is low, and the connected pore size is mainly concentrated in the range of 3-15 nm.The retained hydrocarbon in Well B shale mainly exists in 8-100 nm dolomite intergranular pores, the amount of retained hydrocarbon is large, and the connected pore size is mainly distributed in the range of 10-130 nm.The existence of dolomite and clay minerals is conducive to the development of shale reservoir space, but the biogenic dolomite far away from the source is more conducive to the occurrence and mobility of retained hydrocarbon.The research results can provide theoretical support for the exploration and development of shale oil in Qianjiang Sag.

Studying the microscopic pore structure of reservoir is of great significance of the exploration and development of oil and gas. Therefore, in this paper, the rock samples of the Chang 7 of Yanchang Formation in Zhijing-Ansai area, Ordos Basin are used to carry out experimental analysis of microscopic pore structure and the pore structure parameters such as specific surface area, pore size distribution, pore volume and average pore size of sand and mudstone are studied. The controlling factors of sand-mudstone pore development and the relationship between sand mudstone gas storage and pore structure is also discussed. The results show that the average BET specific surface area of Chang 7 member is 4.252m²/g, the average total pore volume is 1.83*10²cc/g and the average pore size is 185.929nm in sandstone samples of Chang 7 oil layer group in Zhijing-Ansai area. The pores of sandstone in Chang 7 oil layer group of Zhijing-Ansai area is mainly mesopores. Macropores and micropores are next. In the mudstone samples of Chang 7 oil bearing formation of Zhijing-Ansai area, the average BET specific surface area of Chang 7 member is 3.414m²/g, the average total pore volume is 1.3*10-2cc/g and the average pore size is 185.84nm. In the mudstone of Chang 7 oil-bearing formation of Zhijing-Ansai area, the pores of sandstone and mudstone are mainly mesopores, followed by micropores and micropores. Generally speaking, the pores of sandstone and mudstone in Chang 7 member are mainly mesopores, Macropores and micropores are next, nano-pores are developed and they have good adsorption capacity. [ABSTRACT FROM AUTHOR]

BACKGROUND: Porosity is a key parameter for exploration and evaluation of shale gas reservoirs. Rapid and accurate determination of shale porosity is crucial for reserve calculation. At present, there are helium gas method, liquid saturation method and image analysis method applied to shale porosity determination, but the comparison between methods and laboratories is lacking. OBJECTIVES: To evaluate the applicability of different methods for determining shale porosity. METHODS: The characteristics of 69 shale samples from the Longmaxi Formation were studied by analyzing and testing techniques such as X-ray diffraction, argon ion polishing-scanning electron microscopy, and mercury injection-nitrogen adsorption method. Comparison experiments for porosity measurement were conducted among helium method, liquid saturation method and image analysis method. RESULTS: The Longmaxi Formation shale had high clay content, many organic pores, small pore throats, and poor seepage capacity, which made it difficult for foreign liquids and gases to quickly enter the pores, which required high resolution of core image data. The liquid saturation method (alcohol method) used 20 MPa pressure to saturate the sample for 24 hours, resulting in core damage, and the measured porosity deviated from the true value. The image analysis method ignored the micropores (pore size <2 nm) and mesopores (pore size <50 nm) in the mineral matrix and other factors, making the porosity measurement result unreliable. The porosity measurement result of the helium method was closely related to the drying temperature and stabilization time. The higher the temperature, the larger the measured porosity, and if the stabilization time is too short, the porosity result will be smaller than the real values. CONCLUSIONS: After drying the core at 60℃ for more than 24 hours to a constant weight, by setting a reasonable stabilization time, accurate porosity results can be obtained by the helium method. Properly increasing the injection pressure helps to speed up the experimentation rate. [ABSTRACT FROM AUTHOR]

In this study, the influence of acidification and the compound effect of acid and pressure on the multi-scale pore structure distribution characteristics of oil shale were investigated. The pore morphology and elemental distribution characteristics of the oil shale were obtained by scanning electron microscopy–energy-dispersive spectroscopy, and the pore scale distribution characteristics of oil shale were analyzed by mercury injection and nitrogen adsorption. Results showed that acidification increased the pore size of oil shale, the maximum pore size increased from 1.2 to 1.8 μm, and increased to 8.2 μm under the compound action of acid and pressure. Meanwhile, the acid promoted the association of pores inside the oil shale to form fractures, and the effect of pressure substantially enhanced the expansion of fractures, which determined that the compound action was conducive to the formation of complex fractures. In addition, the porosity of oil shale increased by 33.6% after acidification and 54.7% under the compound action of acid and pressure. Acidification mainly promoted the transition from micropores (< 10 nm) to transition-pores (10–100 nm) and mesopores (100–1000 nm) in oil shale, while the transition from transition-pores and mesopores to macropores (> 1000 nm) was promoted under the compound action. Moreover, a new method was used to analyze the full-size pore distribution of oil shale. The study is important for promoting the development of in situ conversion for oil shale. [ABSTRACT FROM AUTHOR]

In this paper, taking the Chang 7 Member of Yanchang Formation in Block H of the Ordos Basin as an example, the fractal characteristics of continental shale were systematically studied based on nitrogen adsorption experiments. The research results show that brittle minerals can significantly improve the pore structures and gas-bearing properties of shale. Nitrogen adsorption experiments show that in a relatively low pressure environment (P0<0.5), the adsorption-desorption curve is in a reversible form. When the relative pressure is large (P0>0.5), a larger hysteresis loop appears. The fractal dimension D1 has a good positive correlation with clay minerals, quartz, calcite and dolomite. The more the specific pore volume of the micropore increases, the greater the increase in the value of fractal dimension D2. In addition, both clay minerals and quartz have a good positive correlation with the fractal dimension D2. The main reason is that the pore types of the shale are mainly interlayer pores of clay minerals and intergranular pores of clay and quartz particles. The correlation between calcite and fractal dimension D2 is poor, and dolomite has a certain negative correlation with fractal dimension D2, which is related to the inhibition of pore development by dolomite. [ABSTRACT FROM AUTHOR]

Pore structure, a critical factor influencing the physical properties of oil and gas reservoirs, shows great variation with the reservoir rock type. Efficient exploration and development of oil and gas resources require comprehensive understanding of pore structure differences between various reservoirs. In this study, to clarify these differences, pore size distributions and pore structure parameters were obtained through low-pressure nitrogen (N2) adsorption–desorption experiments using shale, low-permeability sandstone, and tight sandstone as rock types. Pore space fractal dimension obtained from a proposed calculating method and pore surface fractal dimension obtained from the Frenkel–Halsey–Hill model were combined with N2 adsorption results to analyze quantitatively the pore structures of shale and sandstone. The results show that shale consisted mainly of inkbottle-shaped pores whereas sandstone was composed of slit-shaped pores. Compared with sandstone, shale had a larger specific surface area but smaller average pore diameter and pore volume. In addition, the pore structure heterogeneity and pore surface irregularity of shale were more significant, considering its larger fractal dimensions. Relationships among fractal dimensions and porosity, permeability, and pore structure parameters explained that pore size and pore distribution were the main influencing factors of porosity and permeability. These results highlight the practicability of fractal theory in characterizing pore structure and petrophysical properties of unconventional reservoirs. [ABSTRACT FROM AUTHOR]

This study investigates the effectiveness of an agricultural by-product wheat straw ash (WSA) as an internal curing agent in reducing the autogenous shrinkage of high-performance concrete (HPC). After incineration under different controlled time–temperature conditions, grinding and sieving were performed to obtain two different grades of fine WSA (F-WSA) and superfine WSA (SF-WSA). Subsequently, material characterization tests were carried out, followed by tests for mechanical properties and autogenous shrinkage potential of concrete incorporating 10% and 20% F-WSA and SF-WSA as a partial replacement of cement. The results demonstrated slightly higher compressive and tensile strength of concrete containing SF-WSA compared to control, whereas concrete with F-WSA demonstrated comparable strength results to that of the control concrete. Moreover, a significant reduction in 7 days' autogenous shrinkage was observed in concrete containing 10% and 20% F-WSA by 42% and 25% compared to that of control concrete, respectively. This reduction in autogenous shrinkage increased further to 57% and 40% for concrete with 10% and 20% SF-WSA, respectively. The results of microstructural investigations on paste samples such as FTIR, TGA, and N2 adsorption analyses revealed a more refined and compact microstructure of paste samples with increasing fineness of WSA due to the formation of a more densified C-S-H phase. The improvement of the microstructure is attributable to the improved pozzolanic properties of SF-WSA compared with F-WSA. [ABSTRACT FROM AUTHOR]

Zeolites are well‐known microporous catalysts involved in many industrial applications. Their microporosity yet impedes diffusion of bulky molecules. To overcome this drawback, zeolites with hierarchical bimodal porosity, e. g. micropores and mesopores, are developed. In this context, it is important to develop/use methods able to evaluate accurately the textural properties of mesoporous zeolites. t‐Plot can be in theory used for determining the micro‐ and mesopore surface areas and pore volumes. However, classical t‐plot analysis overestimates the mesopore surface areas and underestimates the micropore volumes for hierarchical micro‐/mesoporous materials. Measurements performed with mechanical mixtures of FAU‐Y and MCM‐41 allows to provide corrections, which are up to date limited to mesoporous FAU‐Y. The present work describes specific corrections of the t‐plot for a broader series of zeolites including MFI, *BEA and MOR, based on a set of mechanical mixtures of zeolites and MCM‐41. Minor correction factors are required for MOR, whilst for MFI and *BEA similar corrections as for the FAU‐Y are inferred for the micropore volume. As far as the surface area is concerned higher correction factors are required for MFI compared to *BEA. This corrected t‐plot analysis is applied to characterize a great variety of mesoporous zeolites prepared by micelle‐templating. [ABSTRACT FROM AUTHOR]

The aim of the study is to determine the effects of structure and content of X, CX in the oxides X/SiO2 (X = Al2O3, TiO2, Al2O3/TiO2) on the surface characteristics. The low-temperature nitrogen adsorption isotherms on the surface of 12 individual and mixed fumed oxides of Si, Ti and Al, as proxies for the Antarctic atmospheric mineral aerosols, were measured by volumetric method. The specific surface areas of the oxides, SBET were calculated by using the Brunauer–Emmett–Teller (BET) theory. The dependence between CX and SBET is not obeyed for the mixed oxides, which can be caused by effects of the reaction temperature of MCln (M = Si, Ti and Al) hydrolysis in the oxygen/hydrogen flame and by different concentration ratios of O2, H2 and MCln on the structural characteristics of the primary particles and their aggregates. The N2 adsorption energy distributions of the oxides surface were calculated by the regularization procedure. It was demonstrated that the surfaces are characterized by high energetic heterogeneity. Result. The Zero-Adsorption Isotherm (ZAI) approach was applied to describe the N2 adsorption in the whole range of its pressures. The ZAI derived in approximation of adsorbed vapor as a set of molecular clusters. The specific surface areas for the oxides, As, maximal numbers of the molecules in the adsorbed clusters, thicknesses of the adsorbed liquid film and the free surface energies of the oxides in the absence of adsorption, γS0, were calculated using the ZAI equations. The As correlates well with SBET and it measures 77.5% of the SBET. The γS0 increases as the N2 average adsorption energy grows. The dependence between γS0 and CX (taking into account γS0 for X) is not obeyed for the mixed oxides. The γS0 for SiO2, Al2O3 and TiO2 rises as the permittivity and the index of refraction increase. The γS0 is within the range of dispersive components of free surface energy, which is determined by other experimental methods and calculated using the Lifshitz’ theory. The obtained parameters allow estimate the activity of the oxide surface with respect to trace gases in the Antarctic atmosphere that is necessary for calculating their partition coefficients between particles and the atmosphere and the kinetics of their removal.

Adsorption isotherms in micropores and mesopores are assessed from nitrogen adsorption isotherm measured on micro-mesoporous carbons and used to determine the micropore and mesopore size distributions. These carbons were obtained by self-assembly of phloroglucinol and formaldehyde in the presence of poly(ethylene oxide)–poly(propylene oxide) – poly(ethylene oxide) triblock copolymer (Pluronic F127) as a soft-template under acidic conditions and subjected to KOH activation. The template used afforded carbons with ordered cylindrical mesopores, while KOH activation enlarged their microporosity. The proposed method allows for the assessment of contributions arising from adsorption in micropores and mesopores, which can be beneficial for further development of pore size analysis of micro-mesoporous carbons. [Display omitted] [ABSTRACT FROM AUTHOR]

Mixed-mode chromatography is becoming increasingly popular in pharmaceutical and biopharmaceutical applications due to its unique selectivity and retention of a variety of compounds. Mixed-mode chromatography is a chromatographic method in which solutes interact with stationary phase through more than one interaction mode or mechanism. It is because of these complex interactions, however, that it is difficult to predict chromatographic behavior of analytes on mixed-mode columns. Characterization of different mixed-mode columns on the basis of surface energy characteristics has not been explored. In this study, different ratios of porous silica (Axia Luna 5 µm Silica – Phenomenex), and C18 (Axia Luna 5 µm C18 – Phenomenex), single mode adsorbents were blended in various ratios and analyzed by Low Temperature Nitrogen Adsorption (LTNA). A variety of commercially available mixed mode columns were also unpacked and the materials were analyzed by LTNA. Adsorption isotherms, surface area, and BET constants were obtained for all the blended materials in various ratios and the mixed-mode materials. A linear relationship between the BET C-constant and the blend ratio of silica has been observed. The results from the commercial mixed mode packing material showed similar surface energy characteristics to single mode C18 materials. This data suggests that the BET C-constant maybe a viable parameter that can be used to characterize mixed-mode columns on the basis of surface energy. Utilizing this surface energy scale in conjunction with the study of retention behaviors on mixed-mode material could lead to improvements in the understanding of method development on mixed-mode columns, allow the comparison of commercialized mixed-mode columns, and even predict retention behavior of an analyte in mixed-mode columns. [ABSTRACT FROM AUTHOR]

In order to examine the pore structure and reveal the fractal geometric nature of shales, a series of laboratory experiments were conducted on lacustrine shale samples cored from the Kongdian Formation. Based on the low temperature nitrogen adsorption, fluorescent thin section and field emission scanning electronic microscope, a comprehensive pore structure classification and evaluation were conducted on shale samples. Fractal dimensions D1 and D2 (with relative pressure of 0–0.45 and 0.45–1.00, respectively) were obtained from the nitrogen adsorption data using the fractal Frenkel-Halsey-Hill (FHH) method. With additional means of X-ray diffraction analysis, total organic carbon content analysis and thermal maturity analysis, the relationships between pore structure parameters, fractal dimensions, TOC content and mineral composition are presented and discussed in this paper. The results show that interparticle pores and microfractures are predominant, whereas organic matter pores are rarely found. The pore morphology is primarily featured with wide-open ends and slit-shaped structures. In terms of pore scale, mesopores and macropores are predominant. The value of fractal dimension D1 representing small pores ranges from 2.0173 to 2.4642 with an average of 2.1735. The value of D2 which represents large pores ranges from 2.3616 to 2.5981 with an average of 2.4960. These low numbers are an indication of few pore types and relatively low heterogeneity. In addition, smaller D1 values reveal that large pores have more complicated spatial structures than smaller ones. The results of correlation analysis show that: 1) D2 is correlated positively with specific surface area but negatively with average pore diameter; 2) D1 and D2 literally show no obvious relationship with mineral composition, TOC content or vitrinite reflectance (Ro); 3) both total Barrett-Joyner-Halenda (BJH) volume and specific surface area show a positive relationship with dolomite content and a negative relationship with felsic minerals content. These results demonstrate that the pore types are relatively few and dominated by mesopores, and the content of brittle minerals such as dolomite and felsic minerals control the pore structure development whilst organic matter and clay minerals have less influence due to low thermal maturity and abundance of clay minerals.