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Palygorskite-bearing claystones and mudstones were deposited in a salt lake in the middle and lower parts of the Neogene Baiyanghe Formation in the Yangtaiwatan Basin, China. The petrological, mineralogical and geochemical characteristics of the sediments were investigated to determine the factors controlling palygorskite formation. The palygorskite claystones and mudstones have distinctly varying mineral compositions. The claystones are composed of detrital minerals, palygorskite and illite, whereas the mudstones consist mainly of mixed-layer illite/smectite and illite. The palygorskite crystals were intact with sharp edges and interwoven with other minerals, indicating an authigenic origin. The chemical characteristics indicate that the palygorskite claystones in the middle part of the Baiyanghe Formation were deposited in a salt lake environment in an arid and hot climate. As the salinity of the lake gradually increased, the detrital minerals such as quartz, feldspar, dolomite and detrital clay minerals dissolved in the alkaline medium, thus providing Si4+, Mg2+and Al3+for the crystallization of palygorskite. The palygorskite coexists with certain amounts of detrital quartz and feldspar with limited roundness and sorting, indicating that the shallow lake of the basin under an oxidation environment may represent a favourable environment for the crystallization of palygorskite.

Gray-black kaolinitic claystones of industrial value are abundant in Upper Carboniferous–Lower Permian coal-bearing strata of the Datong Coalfield of northern China. The main types are tonsteins and cryptocrystalline kaolinitic claystones, distinguished by the thinness and greater crystallinity of kaolinite in the former and by the presence of detrital illite and authigenic pyrite in the latter. In order to determine the formation history of these two types of kaolinitic claystone, the petrological, mineralogical, and geochemical characteristics of borehole samples from the Upper Carboniferous Taiyuan Formation which comprises siliciclastics and coal seams deposited in a coastal environment, were analyzed. In addition to kaolinite, the claystones contain subordinate illite, quartz, pyrite, anatase, feldspar, siderite, and calcite. The tonsteins and cryptocrystalline kaolinitic claystones have different sources, as shown by petrographic data, elemental ratios, and chondrite-normalized rare earth element (REE) patterns. The volcanic origin of the tonsteins is revealed by an abundance of volcanic quartz and vitric fragments as well as Al2O3/TiO2, Zr/Hf, and Nb/Ta ratios consistent with a felsic igneous source. Their REE fraction was derived from feldspars or micas of the parent rocks, and the fraction decreased with alteration of these minerals to kaolinite. The sedimentary origin of the cryptocrystalline kaolinitic claystones is revealed by an abundance of detrital quartz and illite grains derived from either granite or sedimentary upper crust, and by the total REE contents (ΣREE) and (La/Yb)N values which are consistent with granitic material. Their depositional environment was in a transitional (coastal) setting (as shown by intermediate Sr/Ba ratios) hosting an open acidic hydrologic system (as shown by high chemical index of alteration (CIA) values indicative of intensive chemical weathering) that was suboxic to anoxic (as shown by high U/Th ratios and trace-metal enrichment factors). The present chemistry of these claystones was thus controlled by a combination of parent rock type and diagenetic alteration.

The structure of organic matter in anthracite samples of different ranks and coal-derived natural graphites was investigated using XRD, micro-Raman spectroscopy, and HRTEM to determine XRD and Rama...

The macromolecular evolution of coal in proximity to intrusion zones provides a means of exploring the coal to coal-derived natural graphite (CDNG) transitions. Here, samples with different metamor...

Palygorskite-rich mudstone interbedded with gypsum occurs in the Neogene Baiyanghe Formation in the Yangtaiwatan basin, northwest China, but the genesis of palygorskite in the mudstone is unclear. The objective of the present study was to clarify the manner by which the palygorskite evolved by analyzing the mineralogical and geochemical characteristics of the mudstone. The mineralogical composition of bulk-rock mudstone consisted of clay minerals, quartz, feldspar, dolomite, calcite, and gypsum. Palygorskite is dominant in the clay fraction together with illite and accessory chlorite and kaolinite. The interwoven rod-like palygorskite aggregates and delicate palygorskite particles indicated an authigenic origin. The bulk rock of palygorskite-rich mudstone was rich in the trace elements Cs, U, B, Li, Sb, Bi, and As, which, together with REE, all showed very positive correlation with major element oxides Al2O3, Fe2O3, MgO, K2O, and TiO2 of the mudstone, indicating that the REE and trace elements occurred mainly in the clay minerals. The detrital illite, chlorite, and kaolinite were the main original host of the REE and enriched trace elements. Statistical analyses showed that the authigenic palygorskite had strong affinity to such elements compared to the detrital clay minerals. In addition, the chondrite-normalized REE of the bulk mudstone showed essentially the same pattern irrespective of the proportions of detrital illite, kaolinite, chlorite, and authigenic palygorskite present in the samples. Thus, the conclusion reached was that palygorskite was generated from the dissolution of detrital clay minerals. The REE and enriched trace elements in authigenic palygorskite were inherited from the detrital clay minerals.

Coaly graphite is an important natural graphite resource that derived from coal under a natural process that associated with igneous intrusion. Flake graphite is usually used for the chemical synthesis of graphene oxide (GO), the main precursor for preparation of graphene, but few papers pay attention to preparing GO using coaly graphite. In this paper, four kinds of natural coaly graphite with different graphitization degrees were exposed to a modified Hummer’s oxidation method to prepare GO. The flake graphite sample was also used for comparison. The results showed that the structural change process from graphite to GO were significantly affected by the graphitization degree of the original coaly graphite. The relationship between yields of GO and graphitization degrees of the coaly graphite was explored. The mechanism of why the graphite with low graphitization degrees cannot be totally oxidized was proposed. Coaly graphite with a graphitization degree of higher than 80% was easier to be oxidized and yielded the same amount of GO as the flake graphite did, suggesting it is the potential substitute for the flake graphite to produce GO in bulk quantities.

The structure of onset phase of coal derived natural graphite (CDNG for short), semi-graphite, and CDNG subjected to different metamorphic grade were investigated using XRD, Raman spectroscopy, and HRTEM to trace their structural evolution during graphitization. The transitional phases with different structural order exist in graphite field. A classification of these transitional phases is of particular importance to achieve the rational utilization of CDNG. The d(002)-spacing is used to distinguish the pre-phases of highly ordered CDNG (ordered CDNG) and highly ordered CDNG in graphite field. The asymmetry index (AI) of (002) reflection of XRD patterns and Raman parameters D1/G area ratio and FWHM of G band correlate well with d(002)-spacing of CDNG in the zone of semi-graphite to graphite, thus they are also proposed to evaluate the structural order of CDNG. For structural evolution of CDNG during graphitization, at the beginning, the BSUs composed of stacking aromatic layers arrange face to face and tend to link together laterally. Then adjacent BSUs link laterally to form long-range wrinkled layers. With graphitization, the wrinkled layers evolve to flat lamellae and turbostratic structure gradually disappears. Finally, the dislocations in stacking and in-plane defect of flat aromatic layers decrease to attain triperiodic graphite structure.

Polymer nanocomposites containing carbon nanomaterials such as carbon black, carbon nanotubes, and graphene exhibit exceptional mechanical, thermal, electrical, and gas-barrier properties. Although...

The Lutang graphite deposit in Chenzhou, Hunan province, China, is a well-known coal seam-derived graphite (graphite formed from coal during its natural evolution) deposit with proven reserves of 9.5 million tons and prospective reserves of around 20 million tons (2015 data). The graphite occurs at an andalusite bearing sericite quartz chlorite metamorphic mudstone around a c. 530 km2 Qitianling granite intrusion. A set of coal seam-derived graphite samples from the Lutang graphite deposit in Hunan was examined by geochemical, crystallographic, and spectroscopic techniques to assess changes in the degree of graphitization approaching the intrusion. The carbon content, degree of graphitization, and Raman spectral parameters of series coal seam-derived natural graphite samples show a fluctuating increase with increasing proximity to the granite intrusion. The profile of geological structural features has a close spatial correlation with the variations in the degree of graphitization of series coal seam-derived natural graphite, and a strain-enhanced graphitization model is proposed. Moreover, the geographical distribution and the degree of graphitization are positively related to changes in the iron content of chlorite, suggesting a graphitization process promoted by mineral catalysis during metamorphism. A close spatial relationship exists between graphite mineral and chlorite occurrences when approaching the intrusive mass. The results of this research are important for understanding the role of tectonic stress and mineral catalysis on the genesis of coal-derived graphite.

To explore the value of bedside lung ultrasound in the early diagnosis and severity assessment of ventilator-associated pneumonia (VAP).A prospective observational study was conducted in 60 patients with VAP (VAP group) and 62 patients without VAP (control group) who were admitted to department of intensive care unit of General Hospital of Ningxia Medical University from September 2018 to July 2020. The gender, age and underlying diseases of non-VAP group were matched with VAP group. The general clinical data such as gender, age, underlying diseases, department source of the patient, acute physiology and chronic health evaluation II (APACHE II) score, sequential organ failure assessment (SOFA) score were recorded. The body temperature, white blood cell count (WBC), procalcitonin (PCT), oxygenation index (PaO(1) General information: compared with non-VAP group, VAP group had more emergency surgery patients [51.7% (31/60) vs. 33.9% (21/62), P = 0.047], APACHE II score and SOFA score were significantly higher (APACHE II score: 15.4±5.7 vs. 13.4±3.4, P = 0.021; SOFA score: 8.8±4.2 vs. 6.3±3.3, P0.001), body temperature tended to rise (centigrade: 38.3±0.8 vs. 38.0±0.9, P = 0.054), more patients had airway purulent secretions [65.0% (39/60) vs. 41.9% (26/62), P = 0.011], and mechanical ventilation time and length of ICU stay were longer [mechanical ventilation time (days): 10.5 (6.6, 15.0) vs. 4.3 (3.0, 6.0), P0.001; length of ICU stay (days): 14.8 (9.0, 18.0) vs. 6.0 (4.0, 9.1), P0.001], 28-day mortality rate was higher [31.7% (19/60) vs. 9.7% (6/62), P = 0.003]. (2) Diagnostic efficacy evaluation: when lung ultrasound was positive, VPLUS ≥ 3 and PCT0.5 μg/L were used separately for the diagnosis of VAP, the sensitivity was 73.3%, 75.0%, 61.7%, respectively; the specificity was 80.6%, 58.1% and 59.7%, respectively; the 95% confidence interval (95%CI) was 0.685-0.842, 0.574-0.748, 0.514-0.694, respectively,all P0.05, positive lung ultrasound had good sensitivity and specificity. When positive lung ultrasound or VPLUS ≥ 3 were combined with PCT0.5 μg/L for tandem test, the specificity of VAP diagnosis was increased to 95.2% and 83.9%, respectively; but the specificity of VAP diagnosis of positive lung ultrasound combined with PCT0.5 μg/L was higher than VPLUS ≥ 3 combined with PCT0.5 μg/L (95.2% vs. 83.9%, P0.05). (3) Correlation analysis: LUSS showed a significant positive correlation with APACHE II and SOFA score (r values were 0.407, 0.399, P values were 0.001, 0.002, respectively), LUSS had no relation with PaOLung ultrasound can early detect VAP , and its diagnostic specificity is significantly improved when combined with PCT0.5 μg/L. LUSS is closely related to the severity of disease in VAP patients, therefore, lung ultrasound may be an effective method for early diagnosis and efficacy evaluation of VAP patients.

Kaolinite (Kaol) nanoscrolls with a diameter of ~20 to 100 nm and length of ~0.25 to 2 μm were prepared from the exfoliation of Kaol precursor. New interlayer space and lumens could be obtained by delamination and exfoliation of platy Kaol while forming nanoscrolls. The morphological and structural differences between synthetic Kaol nanoscrolls and natural halloysite (Hal) nanotubes were invesigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetry-differential scanning calorimetry (TG-DSC), nitrogen adsorption-desorption techniques. TEM showed that Kaol nanoscrolls are thinner and longer than Hal nanotubes. Kaol nanoscrolls exhibited nitrogen adsorption-desorption isotherms and pore size distribution curves similar to those of Hal but the specific surface area and pore volume of the Kaol nanoscrolls were found to be 2 times higher than those of natural tubular Hal. Both the TG and DTA curves of Kaol nanoscrolls and Hal nanotubes indicated that small amount of adsorbed water was lost below 140 °C. The dehydroxylation of Kaol nanoscrolls occurred at 463 °C, which is between the dehydroxylation temperature of Kaol and that of Hal. The current comparative study of Kaol nanoscrolls and Hal nanotubes suggests that the former could possibly be substituted for the latter for improving some applications because of the higher surface area and different types of pore space of the Kaol nanoscrolls.

Micro-Raman spectroscopic analysis of microscopically distinguishable components in a series of high-rank coals (anthracite to graphitized coal) adjacent to a granitic pluton was used to assess the structural evolution of coal during natural graphitization. Microscopically identifiable components were differentiated into six groups: vitrinite; inertinite; microcrystalline graphite with a fine, granular texture and a low reflectance; pyrolytic carbon with layering normal to particle edges; and needle graphite and flake graphite, both of which are similar to commercial synthetic graphite. Approaching the intrusion, Raman spectra exhibit a distinctly different evolution for vitrinite and microcrystalline graphite: the D1 band of the first-order Raman spectrum becomes narrower and more intense for vitrinite, whereas the D1 band intensity decreases for the granular, microcrystalline graphite. A plot of full width at half-maximum for the D1 band versus R1 (intensity ratio of the D1 to the G band) indicates that...

Energy collection and molecular separation are two emerging applications based on membrane technologies. It remains a challenge to improve the separation performance of molecular channels. Meanwhile, the application of membranes is typically impeded by their poor stability under practical hydrous conditions. Herein, we present the fabrication of a uniformly lamellar membrane using montmorillonite nanosheets as building blocks. We managed to achieve nanofluidic ion transport and molecular separation simultaneously. The membrane nanochannels possess nanofluidic ion transport properties with an output power density of up to 0.18 W m−1 at a membrane thickness of 11.2 μm under a 1000-fold transmembrane concentration difference. The membrane also shows a water permeance of 429 L m−2 h−1 atm−1 at a thickness of 2.5 μm and high separation efficiency for both cationic and anionic dyes. Moreover, the montmorillonite-based membranes can maintain high stability under aqueous conditions with soaking, shaking, and even ultrasonication.

Background.There are currently limited effective pharmacotherapy agents for acute lung injury (ALI). Inflammatory response in the lungs is the main pathophysiological process of ALI. Our preliminary data have shown that colquhounia root tablet (CRT), a natural herbal medicine, alleviates the pulmonary inflammatory responses and edema in a rat model with oleic acid-induced ALI. However, the potential molecular action mechanisms underlining its protective effects against ALI are poorly understood. This study aimed to investigate the effects and mechanism of CRT in rat pulmonary microvascular endothelial cells (PMEC) with TNF-α-induced injury.Methods.PMECs were divided into 6 groups: normal control, TNF-α(10 ng/mL TNF-α), Dex (1×10-6M Dex + 10 ng/mL TNF-α), CRT high (1000 ng/mL CRT + 10 ng/mL TNF-α), CRT medium (500 ng/mL CRT + 10 ng/mL TNF-α), and CRT low group (250 ng/mL CRT + 10 ng/mL TNF-α). Cell proliferation and apoptosis were detected by MTT assay and flow cytometry. Cell micromorphology was observed under transmission electron microscope. The localization and expression of tight junction proteins Claudin-5 and ZO-1 were analyzed by immunofluorescence staining and Western blot, respectively.Results.TNF-a had successfully induced an acute endothelial cell injury model. Dex and CRT treatments had significantly stimulated the growth and reduced the apoptosis of PMECs (allp< 0.05 or 0.01) and alleviated the TNF-α-induced cell injury. The expression of Claudin-5 and ZO-1 in Dex and all 3 CRT groups was markedly increased compared with TNF-a group (allp< 0.05 or 0.01).Conclusion.CRT effectively protects PMECs from TNF-α-induced injury, which might be mediated via stabilizing the structure of tight junction. CRT might be a promising, effective, and safe therapeutic agent for the treatment of ALI.

The conventional approach to exfoliate kaolinite to form aluminosilicate nanoscrolls is very time-consuming. Herein, we report a novel method to prepare aluminosilicate nanoscrolls from kaolinite by catalysis of AlCl3 under mild conditions. This method is highly efficient, environmentally friendly, and can be easily scaled up for mass production.

Due to the fine granularity of CG with the dissemination of non-graphite minerals, highly efficient purification of natural coaly graphite (CG) by low-cost, low-energy consumption and low-pollution methods remains a challenge. In this study, a novel and efficient electrochemical method is demonstrated for purifying natural CG. The electrochemical purification is carried out in a mixed electrolyte containing 0.5 M (NH4)2SO4 and 10% HF with an optimum potential sequence starting at + 2.5 V for a few minutes followed by a short burst of + 5 V. The CG purification mechanism is proposed based on the experimental results. There are three main factors, namely, the type of the graphite anode, the electrolyte and the applied voltage are critical for effectively electrochemical purification. It is interesting to find that the main purified products are graphene mixed with graphite aggregates at a yield of 68%. Raman analysis indicates that the purified CG has fewer structural defects than the natural CG after removing the non-graphite minerals. Moreover, the XPS and FTIR analysis demonstrate that no other functional groups are grafted onto the parent graphite during this purification process. In comparison with the electrolyte only containing HF, the adding of 0.5 M (NH4)2SO4 in the HF electrolyte could reduce the amount of HF by more than 50%, which cuts the cost and alleviates the impact on the environment.

The thermal phase transition of pyrite from coal was studied using thermogravimetry and derivative thermogravimetric, infrared spectroscopy and X-ray diffraction (XRD). According to the XRD results, the phase transition of the pyrite starts at 350 °C, pyrrhotite and magnetite are intermediate products of the oxidation from pyrite to hematite. It was proposed that the main gases and volatile products released during the thermal decomposition of the pyrite are water (H2O) and sulfur dioxide (SO2). The existence of sulfate species in the roasted samples also verified the emissions. These results proved the phase transition of pyrite and explain that they have a rational relationship. The environmental impact related to the thermal phase transition has been discussed, although the pyrolyzation in natural environment is really a very complicated process, it is still able to understand the thermal habits of pyrite in coal by studying pyrite from coal and control surrounding conditions so as to reduce and improve the environmental impact of sulfur pollution.

The structures of cryptocrystalline graphite (CG) and carbon black (CB) have been analyzed using scanning electron microscopy (SEM), transmission electron microscopy (TEM), organic elemental analysis (OEA), X-ray diffraction (XRD), RAMAN and high-resolution transmission electron microscopy (HRTEM). These results indicate that CG has the same elemental composition as CB, with carbon being the major element present. SL sample (CG with low graphitization degree) and CB exhibit similar microcrystalline structures. CG was shown to contain a layered graphitic structure that was significantly different to the primary spherical particles present in CB. It is proposed that these CG sheets may potentially be reduced and delaminated to afford multilayer graphene structures with improved material properties.

Microcrystalline graphite can form from coal naturally as a result of igneous intrusion, but the mechanism of alteration from anthracite to graphite remains elusive. The occurrence of microcrystalline graphite in altered coal seams is not common globally; however, several microcrystalline graphite occurrences that are associated with igneous intrusions are currently being mined commercially in China. In this study, petrographic, geochemical, and X-ray diffraction analyses of a series of Carboniferous coals with different levels of graphitization were used to study transformations in coal structure and chemical composition evolution during natural graphitization. The graphitized coals were collected from mines located at varying distances from a large (~130 km2 in extent) Indosinian-period granite intrusion; the coals in this region have been highly altered by this intrusion. Mean random reflectance of the samples increases from 4.36% to 8.23% approaching the intrusion, but decreases to 4.58% in the most graphitized samples. Vitrinite and inertinite become difficult to distinguish under white light with increased coal rank, and newly formed components including pyrolytic carbon, needle graphite, and flake graphite are seen in the most graphitized samples. The pyrolytic carbon accumulated from a vapor phase that was likely generated during intrusion. The needle and flake graphite occur as fracture and void fills and probably represent graphitization of a mobile phase that migrated through the coal. Timing of generation and the source of the mobile phase is unclear, but predates graphitization and could have been associated with the intrusion event. Microcrystalline graphite, with a characteristic texture consisting of fine granular particles, is the dominant component in the most graphitized samples. Reflectance of microcrystalline graphite using standard coal procedures does not accurately reflect its rank. Approaching the intrusion, structural parameters show a progressive change, especially in highly graphitized coals. Samples closest to the intrusion have transformed into graphite (as confirmed by X-ray diffraction and geochemical data). A plot of volatile matter (VM) versus Rr suggests that the maturation pathway for graphitized coals differs from that of coals that have undergone normal burial maturation. Elemental changes in graphitized coals also differ from coals that have been intruded by smaller-scale sills and dikes. This is probably due to the extreme level of metamorphism associated with the large-scale intrusion that graphitized these coals.

The mass production of graphene with high quality is desirable for its wide applications. Here, we demonstrated a facile method to exfoliate natural graphite into graphene in organic solvent by assisting of urea. The exfoliation of graphite may originate from the “molecular wedge” effect of urea, which can intercalate into the edge of natural graphite, thus facilitating the production of graphene dispersion with a high concentration up to 1.2 mg/mL. The obtained graphene is non-oxidized with negligible defects. Therefore, this approach has great promise in bulk production of graphene with superior quality for a variety of applications.

Intercalation is the promising strategy to expand the interlayer region of kaolinite for their further applications. Herein, the adaptive biasing force (ABF) accelerated molecular dynamics simulations were performed to calculate the free energies involved in the kaolinite intercalation by dimethyl sulfoxide (DMSO). Additionally, the classical all atom molecular dynamics simulations were carried out to calculate the interfacial interactions between kaolinite interlayer surfaces and DMSO with the aim at exploring the underlying force that drives the DMSO to enter the interlayer space. The results showed that the favorable interaction of DMSO with both kaolinite interlayer octahedral surface and tetrahedral surface can help in introducing DMSO enter kaolinite interlayer. The hydroxyl groups on octahedral surface functioned as H-donors attracting the S=O groups of DMSO through hydrogen bonding interaction. The tetrahedral surface featuring hydrophobic property attracted the methyl groups of DMSO through hydrophobic interaction. The results provided a detailed picture of the energetics and interlayer structure of kaolinite-DMSO intercalate.