Average Specific Surface Area Research Articles

Multiscale structural control of thiostannate chalcogels with two-dimensional crystalline constituents

Chalcogenide aerogels (chalcogels) are amorphous structures widely known for their lack of localized structural control. This study, however, demonstrates a precise multiscale structural control through a thiostannate motif ([Sn2S6]4−)-transformation-induced self-assembly, yielding Na-Mn-Sn-S, Na-Mg-Sn-S, and Na-Sn(II)-Sn(IV)-S aerogels. The aerogels exhibited [Sn2S6]4−:Mn2+ stoichiometric-variation-induced-control of average specific surface areas (95–226 m2 g−1), thiostannate coordination networks (octahedral to tetrahedral), phase crystallinity (crystalline to amorphous), and hierarchical porous structures (micropore-intensive to mixed-pore state). In addition, these chalcogels successfully adopted the structural motifs and ion-exchange principles of two-dimensional layered metal sulfides (K2xMnxSn3-xS6, KMS-1), featuring a layer-by-layer stacking structure and effective radionuclide (Cs+, Sr2+)-control functionality. The thiostannate cluster-based gelation principle can be extended to afford Na-Mg-Sn-S and Na-Sn(II)-Sn(IV)-S chalcogels with the same structural features as the Na-Mn-Sn-S chalcogels (NMSCs). The study of NMSCs and their chalcogel family proves that the self-assembly principle of two-dimensional chalcogenide clusters can be used to design unique chalcogels with unprecedented structural hierarchy.

Preparation of activated carbon fibers (ACF) impregnated with metallic silver particles from cotton-woven wastes and its performance as an antibacterial agent

Although activated carbon has been the subject of numerous research applications in water treatment, purification, catalysis, etc., its production is mainly focused on granular and powder presentations due to the commonly used raw materials (e.g., wood, phenolic resin, etc.). Herein, we report an easily established methodology for preparing activated carbon fibers (ACF) using cotton-woven wastes as raw material under chemical activation with H3PO4. We tested different experimental conditions between the activating agent and the cotton fabrics using a randomized-block experimental design with the specific surface area of the activated fibers as the response variable. A highly microporous structure was obtained with an average specific surface area of 1060 m2/g and pore size of 17 Å. The fibers were later impregnated with metallic silver particles using an immersion process in AgNO3 solutions followed by drying and a thermal decomposition to promote the nucleation and precipitation of non-regular shaped silver particles with sizes on the micro and nanoscale within the fiber’s porous. The novel material showed a strong antibacterial effect and a complete inhibition of bacterial culture growth with silver contents as low as 200 ppm. • Cotton-woven wastes are suitable precursors for activated carbon fibers production. • Esterification of cellulose-based raw materials is the activation mechanism. • Production of activated carbon fibers with a specific surface area up to 1200 m 2 /g. • Considerably dimension and structural stability reduction from the original fiber. • High antibacterial activity due to the presence of metallic silver microparticles.

Effect of thermal treatment process on the structure of C/SiO2 composite aerogels

Abstract Carbon/silica composite (C/SiO2) aerogels were synthesized by using tetraethyl orthosilicate, 3-aminopropyltriethoxysilane, trimethylchlorosilane, resorcinol as the silicon and carbon sources, and ethanol as solvent, via the sol–gel process followed by supercritical ethanol drying and thermal treatment. The influence of thermal treatment process on the structure of C/SiO2 composite aerogels was analyzed mainly and measured by Fourier transform infrared spectrometer, X-ray diffraction and nitrogen adsorption–desorption analysis. The results showed that the optimum thermal treatment temperature of C/SiO2 composite aerogels was 1,300°C. With the increase in the thermal treatment time, the linear shrinkage of the composite aerogels increased gradually, and the pore volume, average pore diameter and specific surface area of the composite aerogels increased first and then decreased.

Influences of Clay Mineral and Organic Matter on Nanoscale Pore Structures of the Cretaceous Lacustrine Shales in the Songliao Basin, Northeast China

The Cretaceous lacustrine shales of the Qingshankou Formation (K2qn) from the Songliao Basin are recognized as a potential shale oil reservoir in China. Pore structure of shale within the oil window could be significantly influenced by several factors, including mineral and organic matter (OM) compositions. For a better understanding of the factors controlling the pore structure of these shales, 15 core shales from the K2qn were subjected to low-pressure N2 adsorption measurement for both the initial and solvent extracted samples, and the relationships between shale compositions and pore structure parameters were discussed. The results show that the average specific surface area (SSA) and pore volume (PV) increase from 10.14 m2/g to 29.74 m2/g and from 0.0276 cm3/g to 0.0554 cm3/g respectively after extraction, which suggests that the nanopores in these shales could be significantly occupied by the soluble OM, especially for the pores smaller than 10 nm in size. For the extracted samples, the good positive correlations between the SSA and the illite/smectite (I/S) content indicate that a significant amount of small pores are associated with this mineral, while the overall positive correlations between the PVs with the I/S and OM contents suggest that I/S mineral and organic matter (kerogen) have contributed most to pores lager than 10 nm. It is assessed that OM pores contribute approximately 16% to total PV of these shales. Our results will improve the understanding of pore characterization of the clay- and OM-rich lacustrine shales and provide some implications for shale oil accumulation in the Songliao Basin.

Numerical simulation of the evolution of shock waves and plasma kernels of multi-point laser-induced plasma in supersonic flow

Compared with single-point laser-induced plasma, multi-point laser-induced plasma shows some advantages in ignition and flameholding, but with little research. Therefore, numerical studies of multi-point laser-induced plasma in supersonic flow are conducted using an instantaneous energy deposition model. In the studies, the single-pulse laser energy of every laser focus is 50 mJ, the laser focus configuration is linear, the inflow velocities are from Ma 1.5 to Ma 2.5, and the distances between adjacent focal spots are from 2 to 4 mm. The evolution process of shock waves and plasma kernels in supersonic flow has been described in detail when the inflow velocity is Ma 2 and when the distance between adjacent focal spots is 2 mm. Besides, the evolution law of the velocity field, the streamline, and the plasma kernel position in the flow field have also been analyzed. The results reveal that the volume of the plasma kernel increases rapidly within 15 µs and that the initial shock wave has a strong deflection effect on the supersonic flow. Moreover, the effects of inflow velocities and distances between adjacent focal spots on multi-point laser-induced plasma are compared using the plasma kernel’s average temperature, volume, and specific surface area. Under the conditions of the studies, the results show that the distance between adjacent focal spots is the main reason affecting the evolution. Thus, a distance longer than 4 mm between adjacent focal spots should be avoided for multi-point laser-induced plasma in supersonic flow because the plasma kernel could not be fused in a timely manner.

Constrains of physical properties and geochemical characteristics of country rock on skarn tungsten mineralization: a case study of the Longjiaoshan-Fujiashan skarn tungsten deposit in the Middle-Lower Yangtze River Metallogenic Belt

Previous research on skarn tungsten deposits has mainly focused on causative rocks and skarn minerals. The effect of the physical and mechanical properties and geochemical characteristics of the country rock on the mineralization of skarn tungsten deposits urgently needs to be further studied. A new skarn deposit, Longjiaoshan-Fujiashan, was discovered in the Edong orefield of the Middle-Lower Yangtze River Metallogenic Belt in the contact zone between the causative intrusive rock and the country rocks. The Longjiaoshan-Fujiashan deposit is an ideal research object for the influence of country rock on skarn mineralization. Based on rich ore-hosting and lean ore-hosting strata in the Longjiaoshan-Fujiashan deposit, we conducted analyses of major and trace elements and organic carbon content, specific surface area, porosity, and permeability. Combined with previous studies, we concluded that the difference among the levels of major and trace elements and organic carbon of the strata could be negligible. The conclusion demonstrates that the influence of geochemical properties of limestones on mineralization is small, whereas the physical properties of limestones are likely the main factor influencing mineralization. The pore-type of rich ore-hosting strata (Qixia Formation and Maokou Formation) are fractured pores and organic pores, whereas those of the lean ore-hosting strata (Huanglong Formation and Dabu Formation) are intercrystalline and intercrystalline pores. The average specific surface areas of the rich ore-hosting and lean ore-hosting strata of the limestone samples were 0.1575 and 0.0167 m2/g, respectively. The lower specific surface area is probably not conducive to the adsorption of gas in the ore-forming hydrothermal fluid, which reduces the reaction rate. Similarly, a high pore volume is conducive to the full reaction of the ore-forming hydrothermal fluid with the country rock and the formation of the orebody. The pore diameter of the rich ore-hosting limestone strata in the Longjiaoshan-Fujiashan deposit was in the range of 40–110 μm, and showed “multiple peaks with one main peak and multiple secondary peaks.” The country rock with the reported pore size characteristics is likely to benefit from ore formation. The alteration scale of high porosity and high permeability country rock (i.e., rich ore-hosting strata: 9.0989 MDarcy; lean ore-hosting strata: 2.9699 MDarcy) are conducive to the formation of large skarn-type mineralization. In conclusion, compared with the geochemical properties of the country rock (major and trace elements and organic carbon content), the physical properties of the country rock (specific surface area, porosity, and permeability) have an obvious influence on the mineralization. Determining the influence of different physical property parameters of the country rock on the mineralization process of skarn is of great research value.

The comparative study of shale pore structure between outcrop and core samples of Ziliujing Formation shale from the northeastern Sichuan Basin in China

The pore structure controls the storage and migration of geofluids within shale and ultimately determines its reservoir quality. Therefore, the characterization of shale pore structure has become more and more meaningful in geological engineering research. Due to the complicate sampling procedure and relatively high cost, the shale core samples are usually less in quantity and quite precious. Consequently, the shale outcrop samples, which were deposited in the similar sedimentary environment with shale core samples in the same layer, are always used to indicate reservoir characteristics. However, the pore structure similarities and differences between shale outcrop and core samples in the same layer is still unknown, which restricts the effective use of outcrop samples in shale pore structure characterization and requires detailed investigation. In this study, the pore structure of the outcrop and core samples of Jurassic Ziliujing Formation shale with high clay content from the Northeastern Sichuan Basin in China is quantitatively characterized by N2 adsorption and high-pressure mercury intrusion porosimetry (HPMIP) experiment and is semi-quantitatively revealed by field emission scanning electron microscope (FE-SEM) experiment. The results show that there is an obvious pore structure parameter difference between outcrop and core samples: the average specific surface area of outcrop samples is 8.47 times that of core samples, the average pore volume of outcrop samples is 1.83 times that of core samples; the average microfracture development level of outcrop samples is 1.43 times that of core samples, which is mainly caused by the higher microfracture development level of clay minerals in outcrop samples; the microfracture development direction is chaos in outcrop samples but relatively in order in core samples. However, there are still some pore structure similarities between outcrop and core samples: the whole-aperture pore structure distribution of outcrop and core samples has two similar distribution peaks at 15 ∼22 nm and 25 ∼42 nm; outcrop samples and core samples have similar pore space contributors: clay minerals (CM) pores > organic matter (OM) pores + quartz and feldspar (QF) pores while microfractures are mainly provided by clay minerals; the pore size distribution of OM and QF pores in outcrop samples were also similar to core samples. Overall, the pore structure of outcrop samples has certain indicative significance in terms of main pore size distribution interval, the relative contribution of different types of pores and the pore characteristics of OM, which shows the limited applicability of outcrop samples in shale pore structure characterization.

Ni doping effect on the electronic, structural and optical properties of ZnO nanoparticles prepared by Co-precipitation route

Nanoparticles (NPs) synthesized by the co-precipitation technique show many attractive properties such as small particle size, high crystallinity, high average pore diameter and high specific surface area. However, numerous reports show that some characteristics of the Ni-doped ZnO (NZO) NPs remain controversial such as optical bandgap (Eg), surface morphology and defect level. In this study, pure ZnO and NZO NPs at different Ni contents (x) were successfully prepared using the co-precipitation method. Phase analysis confirms the hexagonal wurtzite crystallinity of the samples. XRD peak shows that the Ni may substituted ZnO structure as the peaks shift toward higher angles with increasing x. Meanwhile, the formation of NiO secondary phases was significant at 12.50% Ni content. Densely packed spherical shaped structures with nanoparticle agglomeration are observed at low x, while some nanorod shaped structures appear at higher x. The stretching vibrations of the Zn–O bond are observed in the NZO NPs. The absorption edge shifts to higher wavelengths with the increase in x. This study provides consistent results in the phase analysis, morphology and structural parameters. The decrease in Eg agrees with the photoluminescence measurements. The emission spectra confirm the presence of interstitial zinc and singly ionized oxygen vacancies.

Simultaneous oxidation of aromatic compounds using Sr‐doped lanthanum manganites as catalysts

Strontium-doped lanthanum manganites, La1-xSrxMnO3 (LSMO), are promising and affordable catalysts for oxidative degradation of volatile organic compounds. LSMO catalysts (x = 0, .1, .2, and .3) were prepared by the citrate-nitrate autocombustion (CNA) and coprecipitation synthesis. The phase composition was confirmed by X-ray diffraction and Rietveld refinement analysis, while the oxygen content was determined by Mohr's salt permanganate titration. Morphology and porosity of prepared catalysts was correlated to catalytic oxidation of benzene, toluene, ethylbenzene and o-xylene. It was observed that both synthesis methods yielded catalysts of similar average pore size diameter and specific surface area, but the pore size distribution differed: CNA-prepared catalysts had a multimodal pore size distribution, while the coprecipitated ones had a single maximum at 4 nm. Catalysts prepared by the CNA method have shown a higher catalytic activity in the temperature range 373–723 K, as the presence of Mn3+/Mn4+ mixed valences increased their reducibility.

Novel biologically synthesized metal nanopowder from wastewater for dye removal application.

A novel adsorbent based on metal sulfide nanoparticles (MeSNPs) was biologically synthesized from metallic wastewater and examined for azo dyes removal from aqueous solution in batch and continuous systems. The size of the MeSNPs was in the range of 8-10nm, with an average specific surface area of 120.4 m2/g. Batch adsorption study was then carried out using Direct Red 80 (DR 80) and Mordant Blue 9 (MB 9) as the model azo dyes by varying MeSNPs dosage, contact time, pH, and initial dye concentration. More than 99% removal efficiency of both the dyes was achieved by using MeSNPs at the following optimum conditions: 200mg dosage, pH 2, 6min contact time, and 100mg L-1 initial dye concentration. The batch sorption isotherm results were described using the Sips model, with the maximum predicted capacity values of 143.7 and 198.3mg of dye per gram of adsorbent for DR 80 and MB 9, respectively. Besides, the sorption kinetic data for both the dyes followed the pseudo-second-order rate. Furthermore, maximum desorption efficiency values of 93% for DR 80 and 97% for MB 9 were achieved using an aqueous solution of pH 12, thus indicating that the adsorbent can be regenerated and reused further. Dynamic adsorption of the dyes was studied using a fixed-bed column with the MeSNPs as a function of liquid flow rates. The results showed an increase in breakthrough time with a decline in the flow rates for both DR 80 and MB 9 and the breakthrough behavior was explained using Thomas, Clark, and Yoon-Nelson models.

Structural, magnetic and adsorptive properties of nano spinel of cobalt aluminate doped with nickel for Cr(VI) removal

Nanocrystallines of cobalt aluminate spinel doped with Nickel (MAl2O4; M = Co+2, Ni+2) were synthesized by sol-gel method. The MAl2O4 samples were prepared by using aluminum nitrate; cobalt nitrate, nickel nitrate, citric acid and diethylene glycol mono ethyl ether as precursor materials. The nanocrystallines spinel were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction(XRD), Thermal gravimetric (TGA), Scanning electron microcopy (SEM) with the energy dispersive X-ray spectroscopy (EDX) methods. The Specific surface area of the synthesized powders was measured with a Brunauer-Emmet-Teller (BET) apparatus using N2 adsorption. According to obtained XRD patterns the formation of single phase MAl2O4 completed up 800 °C. The average crystallite's sizes spinel and specific surface area at 800 °C were estimated about 11.07 nm and 154 m2 g−1, respectively. The results of SEM analysis show that the nanoparticles shape are as spherical shape, uniform and a little agglomerated. The magnetic behavior of spinels showed the magnetization decreased with increasing nickel ions. Adsorption of Cr(VI) by as prepared spinels were considered. The highest percent of Cr(VI) adsorption was occurred at contact time of 45 min, pH 7.0, and adsorbent dose of 2 g L−1. The order of adsorption capacity of sorbent samples for Cr(VI) removal was as follow: Ni0.5Cu0.5Al2O4 >Ni0.7Cu0.3Al2O4 >Ni0.3Cu0.7Al2O4>NiAl2O4> CoAl2O4. Kinetic studies indicated that the adsorption process follows by pseudo second-order model. Thermodynamic results revealed that the adsorption of Cr(VI) is endothermic, spontaneously process and feasible in the range of 298–338 K.

In English

Boron carbide (BC, B15-xCx B4C) has a unique combination of properties. This makes it a material for priority applications for a wide range of engineering solutions. The high melting point and heat resistance of the compound contribute to its use in refractory conditions. Due to its extreme abrasion resistance, B4C is used as an abrasive powder and coating. Due to its high hardness and low density, B15-xCx has ballistic characteristics. It is usually used in nuclear programs as an absorbent of neutron radiation Boron carbide ceramics (B15-xCx or BC) may lose strength and toughness due to the amorphization effect under high shear stresses. Aluminum dodecaboride AlB12 or B12Al, as well as boron carbide B12 [(CCC) x (CBC) 1-x] have common structural units B12 family of boron-icosahedral structures. The bond between icosahedrons is mainly due to atoms (Al, Si, O) or chains (CMC), where M is Al, Si, B, C. Doping BC powder with a small amount of AlB12, in cases of shock-shear stress, triggers the mechanism of "micro-cracking". Micro cracks and pores are formed in ceramics. The breakdown voltage decreases. AlB12 synthesis is associated with known difficulties. On the other hand. The production of metal-ceramic materials for several decades is associated with the interaction of liquid aluminum and boron nitride. The calculation of this reaction shows that it is exothermic. Avoiding oxidation in vacuum, the reaction occurs through the formation of aluminum nitride and aluminum dodeca-boride. In contrast to the liquid state, the process continues until the end, at conditional temperatures of evaporation of aluminum with slight changes in vacuum. The reaction product is a mixture of nanosized AlN/AlB12 powders with a weight ratio of 3/1 ready for baking without grinding. The acid-base properties of the nanosized powder mixture AlN + AlB12, the products of the interaction BN + Al in vacuum, which are used optionally, emit separate in pure phases of aluminum nitride and aluminum dodeca-boride. The yield of AlB12 is ~ 25%, boron reaches ~ 100%. The average particle size of the AlB12 powders according to TEM and ACS X-rays (area of coherent X-rays scattering), L (nm) is LTEM=110-150nm, LACS=51-70nm. The average specific surface area of the powder according to BET, TEM and ACS, SBET.m2/g=21,0-15,0; STEM.m2/g=21,4-15,4; SACS.m2/g=46,1-33,6; (at 1460 and 1640K, respectively).

Membrane synthesis via in-situ pore formation in silica gels through dynamic miscibility with soybean oil

The dynamic miscibility between soybean oil and organic silica precursors during sol-gel synthesis was used to tailor the microstructure of gels made with tetraethoxysilane (TEOS) or TEOS + methyltrimethoxysilane (MTMS). Soybean oil was investigated as an environmentally friendly and cheaper alternative to other common porogens. Oil concentrations of 9.09 v/v% and 33.33 v/v% were studied. For both TEOS and TEOS+MTMS gels, the miscibility of the oil and precursor decreased as the silica gel network formed, leading to oil-rich regions within the silica matrix. Solvent exchanges on gels or calcined on dried gels (i.e., xerogels) were performed to remove the oil from the silica, creating membranes with hierarchical pore structures. The pore structure of TEOS-MTMS gels appeared finer and more interconnected compared to the isolated pores observed in gels made with only TEOS. Xerogel membranes made with TEOS+MTMS had higher specific surface areas (SSAs) than those made with TEOS. For oil concentrations of 33.33 v/v%, xerogels made from TEOS+MTMS had an average SSA of 1068 + 113 m2 g−1, an order of magnitude higher than the average SSA of 103 + 6 m2 g−1 for xerogels made with TEOS.

Coal Macrolithotype Distribution and Its Genetic Analyses in the Deep Jiaozuo Coalfield Using Geophysical Logging Data

Coal macrolithotypes are closely correlated with coal macerals and pore–fracture structures, which greatly influence the changes in gas content and the coal structure. Traditional macrolithotype identification in coalbed methane (CBM) wells mostly depends on core drilling observation, which is expensive, time-consuming, and difficult for broken core extraction. Geophysical logging is a quick and effective method to address this issue. We obtained coal cores from 75 wells in the deep regions of the Jiaozuo Coalfield, northern China, quantitatively analyzed the logging cutoff number corresponding to various macrolithotypes, and established natural γ (GR), deep lateral resistivity (LLD), and γ–γ log (GGL) response rules for each coal macrolithotype. The formation mechanisms of different coal macrolithotypes are discussed from the perspective of coal facies and pore structures. The results show that GGL decreased but GR and LLD increased from bright coal to dull coal. Most coal macrolithotypes can be distinguished based on the established thresholds of various logging curves. However, excessively high or low ash yields significantly affect the validity of identification. The vertical coal macrolithotypes attributed to the peat marsh environment in Shanxi Formation mostly comprise three to six sublayers; dull or semi-dull coals are predominant close to the 21 coal seam, and the bright or semi-bright types usually appear in the middle part. The semi-bright and bright coals are usually vitrinite rich, whereas the semi-dull and dull coals are primarily inertinite rich. For pore structure arguments, the highest average specific surface area (SBET) and the total pore volume (VBJH) are found in bright coals, followed by dull and semi-bright coals; those of semi-dull coals are the lowest. However, SBET and VBJH change significantly for different samples, even though the coal macrolithotype is the same. Therefore, the macrolithotype is not the key factor determining the coal parameters of pore structures. Rapid and effective identification of coal macrolithotypes can help determine the CBM enrichment area, the CBM well location, and the exploration horizon.

Controlling Factor Analysis of Microstructural Property and Storage Capacity of Deep Longmaxi Formation Shale in Sichuan Basin

As the commercial development of shallow shale gas reservoirs has been successfully achieved in Sichuan Basin, the deep shale gas reservoirs become the key development target in the next step. The accurate quantitative characterization of the fluid storage and structural properties of deep shale is of great significance in resource evaluation and gas exploitation. In this study, fifteen deep Longmaxi Formation shale samples belonging to three sublayers are collected from the L208 well area, Luzhou Block, southern Sichuan Basin. Nuclear magnetic resonance and nitrogen adsorption are conducted on these samples to obtain the fluid storage capacity and microstructural information. Pore fractal dimension and surface fractal dimension are interpreted from these experimental data for quantitative evaluation of the pore distribution complexity and pore surface irregularity, respectively. The controlling factors of storage and microstructural properties of these deep shales are analyzed. From the perspective of stratigraphic division, the shales belonging to the lower sublayers possess a larger transverse relaxation time of the main peak, a weaker nitrogen adsorption amount, a lower pore volume, a lower specific surface area, and a higher surface fractal dimension as compared to those of the shales from the upper sublayer. From the perspective of shale composition, clay mineral content and total organic carbon content are the main and minor controlling factors of the storage capacity, pore fractal dimension, and surface fractal dimension of deep Longmaxi shale, respectively. Moreover, the pore surface irregularity is relevant to the average pore diameter and specific surface area.

Preparation and characterization of cellulose nanocrystals from spent edible fungus substrate.

Spent edible fungus substrates were identified as potential sources to produce cellulose derivatives, namely purified cellulose and dicarboxyl cellulose nanocrystal (DCNC). Purified celluloses were obtained via chemical treatments and then oxidized by sequential periodate-chlorite without mechanical process. The structural properties of the DCNCs were characterized by transmission electron microscopy (TEM), Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and thermal gravimetric analysis (TGA). XRD results showed that the cellulose I structure was maintained, however, the crystallinity index decreased after oxidation process. The initial pyrolysis temperature of DCNCs ranged from 242 to 344 °C. TEM results revealed that DCNC was rod-shaped with an average length and width of 130.88 nm and 7.3nm, respectively. The average specific surface area (SSA) was 366.67 m2 g-1 . The carboxyl content was around 3.485 mmol g-1 . Finally, the adsorption capacity for contaminations was 76.98, 126.22, 64.44 and 9.63 mg g-1 for copper ion (Cu2+ ), lead ion (Pb2+ ), chromium (Cr3+ ) and amoxicillin (AMX), respectively. This work showed a sequentially chemical oxidation for preparing nanocellulose from secondary agricultural waste with many functional applications. © 2021 Society of Chemical Industry.

The Alkaline Fusion-Hydrothermal Synthesis of Hydroxyapatite-Zeolite (HAP-ZE) from Blast Furnace Slag (BFS): Effects of Reaction Temperature

This study was performed to investigate the effects of reaction temperature on the alkaline fusion-hydrothermal preparation of hydroxyapatite-zeolite (HAP-ZE) using blast furnace slag (BFS) as raw material. Firstly, HAP-ZE samples were obtained under various reaction temperatures; then the analysis was carried out utilizing XRD, FT-IR, BET/BJH, XRF, FE-SEM and EDX. The results reflect that the optimum reaction temperature for preparing HAP-ZE from blast furnace slag (BFS) using alkaline fusion-hydrothermal treatment is around 100 °C. The HAP-ZE synthesized at 100 °C had the largest specific surface area (SSA) value. Under 100 °C aging, the main phases in HAP-ZE were zeolite and HAP with the average SSA is 44.22 m2·g−1. Molar ratio of Ca/P, Si/Al and Na/Al is 1.61, 1.31, 1.75, respectively. Additionally, HAP-ZE crystals with a diameter of about 500 nm form an open frame structure with coral surface morphology could be clearly observed at 100 °C. The observed surface morphology feature agrees well with that for HAP-ZE previously reported, again elucidating the successful formation of HAP-ZE.

Relationship between Organic Geochemistry and Reservoir Characteristics of the Wufeng-Longmaxi Formation Shale in Southeastern Chongqing, SW China

Shale gas accumulates in reservoirs that have favorable characteristics and associated organic geochemistry. The Wufeng-Longmaxi formation of Well Yucan-6 in Southeast Chongqing, SW China was used as a representative example to analyze the organic geochemical and reservoir characteristics of various shale intervals. Total organic carbon (TOC), vitrinite reflectance (Ro), rock pyrolysis, scanning electron microscopy (SEM), and nitrogen adsorption analyses were conducted, and a vertical coupling variation law was established. Results showed the following: the Wufeng-Longmaxi formation shale contains kerogen types I and II2; the average TOC value at the bottom of the formation is 3.04% (and the average value overall is 0.78%); the average Ro value is 1.94%; the organic matter is in a post mature thermal evolutionary stage; the shale minerals are mainly quartz and clay; and the pores are mainly intergranular, intragranular dissolved pores, organic matter pores and micro fractures. In addition, the average specific surface area (BET) of the shale is 5.171 m2/g; micropores account for 4.46% of the total volume; the specific surface area reaches 14.6%; and mesopores and macropores are the main pore spaces. There is a positive correlation between TOC and the quartz content of Wufeng-Longmaxi shale, and porosity is positively correlated with the clay mineral content. It is known that organic pores and the specific area develop more favorably when the clay mineral content is higher because the adsorption capacity is enhanced. In addition, as shale with a high clay mineral content and high TOC content promotes the formation of a large number of nanopores, it has a strong adsorption capacity. Therefore, the most favorable interval for shale gas exploration and development in this well is the shale that has a high TOC content, high clay mineral content, and a suitable quartz content. The findings of this study can help to better identify shale reservoirs and predict the sweet point in shale gas exploration and development.

Evaluation of the baseline carbon sequestration rates of Indo‐Pacific temperate and tropical seagrass meadow sediments

AbstractSeagrass meadows have great capacity to sequester and store organic carbon (OC) in sediments for the long term and have been considered as a carbon dioxide sink for national greenhouse gas inventories in the Intergovernmental Panel on Climate Change Guidelines. Therefore, there is an urgent need to determine a reliable, well‐constrained estimate of the baseline long‐term OC sequestration (burial) rate in seagrass meadows, evaluate its spatial and temporal variability, and understand the mechanisms that control the variability. Here, we report data on OC stocks and long‐term sequestration rates for 14 selected sediment cores collected from temperate and tropical seagrass meadows and adjacent bare areas in Japan and Thailand. We also tested several different radiocarbon dating calibration methods to evaluate sedimentation rates and identified potential complicating factors. The estimated OC sequestration rate ranged from 3.7 to 161 kg C ha−1 year−1, which is generally lower and less variable than reported global representative values, presumably because of differences in the time scale considered. The OC sequestration rate for temperate seagrass meadows was correlated with the average specific surface area of sediment, implying that geophysical and hydrodynamic factors constrain the long‐term OC sequestration rate. The baseline OC sequestration rate may be better constrained by the method used here, focusing on time scales of centuries to millennia, while the evaluation of OC sequestration on shorter time scales may be more suitable for assessing the environmental additionality of climate mitigation efforts based on blue carbon manipulation.

Heterogeneity Characteristics of Lacustrine Shale Oil Reservoir Under the Control of Lithofacies: A Case Study of the Dongyuemiao Member of Jurassic Ziliujing Formation, Sichuan Basin

The lacustrine shale in the Dongyuemiao Member of the Fuling area, Sichuan Basin, is widely distributed and has huge shale oil resource potential. It is one of the important replacement areas for shale oil exploration in China. To investigate the key shale oil evaluation well, Well FY10, in the Fuling area, X-ray diffraction (XRD) mineral analysis, Rock-Eval, argon ion polishing-scanning electron microscope (SEM), Mercury injection capillary pressure (MICP), and low pressure nitrogen adsorption were launched to determine the heterogeneity of the pore system in the lacustrine shale of the Dongyuemiao Member. The mineral composition exhibits a high degree of heterogeneity, and the shale can be divided into two main lithofacies: argillaceous shale and mixed shale. The porosity ranges from 2.95 to 8.43%, and the permeability ranges from 0.05 to 1.07 × 10−3 μm2. The physical properties of mixed shale are obviously better than those of argillaceous shale. Inorganic mineral pores, such as linear pores between clay minerals and calcite dissolution pores, are mainly developed, while a small amount of organic pores can be observed. The average total pore volume (Vp) is 0.038 ml/g with an average specific surface area of 5.38 m2/g. Mesopores provide the main Vp (average 61.72%), and micropores provide mostly specific surface area. TOC imposes a strong controlling effect on the development of micropores. Clay minerals are the main contributors to mesopores and macropores. The organic-inorganic interaction during the process of diagenesis and hydrocarbon generation controls the formation of shale pore systems.