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The aim of the study is to examine the textural structure and organic functional groups of horse-donkey, cow, dog, and sheep bones by nitrogen gas adsorption-desorption and Fourier Transform Infrared (FT-IR) spectroscopic methods, respectively. For this purpose, textural properties such as BET (Brunauer-Emmett-Teller) surface area, total pore volume, average pore diameter, and surface organic functional groups were determined by nitrogen gas adsorption/desorption at -196 oC and FT-IR spectral analysis methods, respectively. It was observed that the nitrogen gas adsorption isotherms obtained from the BET analysis results were similar to Type-V, which indicates that they have a mesoporous and/or macroporous textural structure, in the IUPAC nitrogen gas isotherm classification. In addition, it was determined from the FT-IR analysis results that they mainly contain organic functional groups such as amine, alcohol, carboxylic acid, ester, ether. [ABSTRACT FROM AUTHOR]

We studied the effects of soil pH (3.29, 4.74 and 5.32) on nitrogen uptake and its use efficiency by tea bush. The results showed that with the increase of soil pH value (3.29 ~ 5.32), the nitrogen utilization efficiency of tea bushes increased from 94.28 % to 461.14 %, the nitrogen absorption efficiency increased from 1.05 % to 3.95 % and the nitrogen physiological utilization efficiency increased from 89.79 % to 116.74 %. Besides with the increase of soil pH, the activity of spoil enzymes (Urease, protease, asparaginase, N-acetamide glucose ribosidase) in tea rhizosphere soil was significantly increased, while, that of nitrate reductase and nitrite reductase was decreased significantly. With the increase of soil pH, the expression of nifH gene in tea rhizosphere soil increase significantly, while expression of amoA-AOA, amoA-AOB, nirK, nirS, narG and nosZ gene was decreased. Correlation analysis showed that pH value in tea rhizosphere soil was significantly and positively correlated with nitrogen utilization efficiency, nitrogen uptake efficiency, nitrogen physiological utilization efficiency, urease activity, protease activity, asparaginase activity, N-acetamide glucose ribosidase activity and the expression of nifH gene. Correlation analysis was negatively correlated with nitrate reductase activity, nitrite reductase activity and the expression of amoA-AOA, amoA-AOB, nirK, nirS, narG and nosZ gene. The results indicated that soil acidity significantly affected the ability of soil nitrogen conversion and nitrogen absorption and utilization ability of tea bushes. [ABSTRACT FROM AUTHOR]

The N K-edge X-ray absorption near edge structure (XANES) spectra of the purine-containing nucleotide, guanosine 5'-monophosphate (GMP), in aqueous solution are measured under various pH conditions. The spectra show characteristic peaks, which originate from resonant excitations of N 1s electrons to n * orbitals inside the guanine moiety of GMP. The relative intensities of these peaks depend on the pH values of the solution. The pH dependence is explained by the core-level shift of N atoms at specific sites caused by protonation and deprotonation. The experimental spectra are compared with theoretical spectra calculated by using density functional theory for GMP and the other purine-containing nucleotides, adenosine 5'-monophosphate, and adenosine 5'-triphosphate. The N K-edge XANES spectra for all of these nucleotides are classified by the numbers of N atoms with particular chemical bonding characteristics in the purine moiety. [ABSTRACT FROM AUTHOR]

This study used the rice cultivar Suijing 18 to investigate the effects of morphological characteristics, photosynthetic changes, yield, as well as nitrogen absorption and utilization. The interaction between seeding rate and nitrogen rate was also assessed to identify the most suitable values of the dominant population for both factors under dry cultivation. Furthermore, the photosynthetic physiological characteristics of the upper three leaves in the dominant population were also explored. The results showed that a combination of 195 kg/ha seeding rate and 140 kg/ha nitrogen rate achieved high yield, high nitrogen utilization, and moderate morphological characteristics. This was achieved by a coordination of the combined advantages of population panicle number and spikelets per panicle. The photosynthetic potential of the population was improved by coordinating the reasonable distribution of light energy in the upper three leaves, which led to the emergence of a dominant rice population under dry cultivation. [ABSTRACT FROM AUTHOR]

In order to study the adsorption characteristics of H2S, CH4 and N2 by coal under different conditions, the new macromolecular structure model of Dongqu No. 2 was constructed, and the grand canonical Monte Carlo (GCMC) method was used to simulate the adsorption process of three types of gases in coal. The dependence of adsorption capacity of coal on its temperature, pressure and moisture content was analyzed. The results show that with the increase of pressure and temperature, adsorption isotherms of all the three gases follow Langmuir model. For pressure greater than 2 MPa, the influence of temperature on adsorption capacity was greater than that of pressure. With rise in temperature, the decrease in rate of H2S adsorption was least and drops in the heat of adsorption of H2S most. This indicates that the adsorption of H2S on coal is more stable than those of CH4 and N2. As the water content of coal increased, its adsorption capacity for the present three gases decreased linearly, and the capacity for H2S (1.77 mmol/g) changed the most. The reduction of free volume linearly and preferential occupation of adsorption sites by water molecules are the main reasons for the highest change in the adsorbed amount of H2S gas. [ABSTRACT FROM AUTHOR]

Molecular dynamics simulations are performed to determine the solubility and diffusion coefficient of carbon dioxide and nitrogen in poly(methyl methacrylate) (PMMA). The solubilities of CO2 in the polymer are calculated employing our grand canonical ensemble simulation method, fixing the target excess chemical potential of CO2 in the polymer and varying the number of CO2 molecules in the polymer matrix till establishing equilibrium. It is shown that the calculated sorption isotherms of CO2 in PMMA, employing this method well agrees with experiment. Our results on the diffusion coefficients of CO2 and N2 in PMMA are shown to obey a common hopping mechanism. It is shown that the higher solubility of CO2 than that of N2 is a consequence of more attractive interactions between the carbonyl group of polymer and the sorbent. While the residence time of CO2 beside the carbonyl group of polymer is about three times higher than that of N2, the diffusion coefficient of CO2 in PMMA is higher than that of N2. The higher diffusion coefficient of CO2, compared to N2, in PMMA is shown to be due to the higher (≈3 times) swelling of polymer upon CO2 uptake. [ABSTRACT FROM AUTHOR]

Field experiments were conducted over two years to evaluate the effects of planting density and nitrogen input rate on grain yield and nitrogen use efficiency (NUE) of inbred and hybrid rice varieties. A significant interaction effect was observed between nitrogen input and planting density on grain yield. Higher number of panicles per square meter and spikelets per panicle largely accounted for the observed advantage in performance of inbred, relative to hybrid varieties. Compared with high nitrogen input rate, nitrogen absorption efficiency, nitrogen recovery efficiency, and partial factor productivity increased by 24.6%, 28.0%, and 33.3% in inbred varieties, and by 32.2%, 29.3%, and 35.0% in hybrids under low nitrogen input, respectively. Inbred varieties showed higher nitrogen absorption efficiency, nitrogen recovery efficiency, and partial factor productivity than hybrids, regardless of nitrogen input level. Nitrogen correlated positively with panicle number, spikelets per panicle, biomass production at flowering, and after flowering in inbred varieties but only with panicle number and biomass production at flowering in hybrids. Inbred varieties are more suitable for high planting density at reduced nitrogen input regarding higher grain yield and NUE. These findings bear important implications for achieving high yield and high efficiency in nutrient uptake and utilization in modern rice-production systems. [ABSTRACT FROM AUTHOR]

We have investigated the effect of co-absorbed CO and reaction temperature on the angular distribution of N2 desorption by N2O decomposition under the steady state of N2O-CO reaction on Rh(110). Spatial distributions of desorbing product N2 emission have been measured at various surface temperatures and CO coverages. The decomposed N2 collimates at 48°-61° off normal in the parallel plane to [001] and [110] directions, indicating that adsorbed N2O just before the decomposition is oriented along the [001] direction. Although the inclined and collimated N2 desorption is always observed at any steady-state CO coverage and reaction temperature, the shape of the collimated N2 distribution varied dependent on the co-adsorbed CO coverage. The distribution becomes sharp and shifts toward the surface normal direction with increasing CO coverage. These effects of adsorbed CO on the angular distribution of N2 are interpreted by the collision of desorbed N2 with co-adsorbed CO. [ABSTRACT FROM AUTHOR]

Oscillator strengths of 23 electric-dipole-allowed bands of 14N2 in the 86.0–89.7 nm (111 480–116 280 cm-1) region are reported from synchrotron-based photoabsorption measurements at an instrumental resolution of 6.5×10-4 nm (0.7 cm-1) full width at half maximum. The absorption spectrum comprises transitions to vibrational levels of the cn 1Πu (n=3,4), o3 1Πu, and cn+1′ 1Σu+(n=3,4) Rydberg states as well as the b 1Πu and b′ 1Σu+ valence states. The J dependences of band f-values derived from the experimental line f-values are reported as polynomials in J(J+1) and are extrapolated to zero nuclear rotation in order to facilitate comparisons with the results of coupled Schrödinger equation calculations. Many bands in this study are characterized by a strong J dependence of the band f-values and display anomalous P-, Q-, and R-branch intensity patterns. Predissociation line widths are reported for six bands. The experimental f-value and line-width patterns inform current efforts to develop comprehensive spectroscopic models for N2 that incorporate rotational effects and predissociation mechanisms, and are critical for the construction of realistic atmospheric radiative-transfer models. [ABSTRACT FROM AUTHOR]

Photoluminescence (PL) spectra of bound excitons were measured in uniaxially strained GaP by performing shock-wave experiments at liquid nitrogen temperatures. GaP samples doped with sulfur or nitrogen were compressed up to 3 GPa when subjected to uniaxial strains along the [100] crystallographic orientation. PL lines from shallow sulfur donors redshifted upon compression, tracking the reduction in the indirect band gap. PL lines related to the isoelectronic NN1 pairs, in contrast, exhibited splitting and nonlinear blueshift. An empirical approach was used to model the NN1 behavior. It was shown that the splitting pattern is consistent with the previously proposed symmetry of NN1 defects and nonlinearities resulting from the reduction in the exciton binding energy. At high stresses, the NN1 lines disappeared due to the ionization of bound excitons. [ABSTRACT FROM AUTHOR]

Nitridation of the SiO2/SiC interface yields a reduction in interface state density, immunity to electron injection, as well as increased hole trapping. It is shown that the accumulation of nitrogen at the oxide/semiconductor interface is solely responsible for these three effects. The evolution of the density of interface states, electron traps, and hole traps is measured in metal-oxide-semiconductor capacitors as a function of the nitrogen content which is varied by adjusting the gate oxide NO annealing time. A rate equation is derived to model the change in the interface state density, observed at various energy levels, in terms of nitrogen binding cross-sections. While the generation of acceptor interface states upon electron injection is suppressed after minimum N incorporation, the density of oxide hole traps appears to scale linearly with the amount of nitrogen. The origin and the properties of the N-induced hole traps resembles those of the defects responsible for enhanced negative bias temperature instability observed in nitrided silicon devices. It is proposed that the binding of nitrogen is not exclusively driven by the passivation of defects at the semiconductor surface but also results in the formation of a silicon oxynitride layer redefining the interface. [ABSTRACT FROM AUTHOR]

Cu2(OH)3Cl with an average size of 5–10 μm have been synthesized by a simple hydrothermal reaction with a yield of ∼100%. After the as-prepared Cu2(OH)3Cl was treated with NaOH solution, the green crystals were converted to blue sisal-like Cu(OH)2 with needle-like nanorods pointing out radially from the core. These nanorods were about 100–200 nm in diameter and 10 μm in length. Using the sisal-like Cu(OH)2 as sacrificial precursor, CuO with a well-preserved morphological feature of the precursor was formed through thermal treatment. The samples were characterized by scanning electron microscopy, energy dispersive X-ray, X-ray diffraction, X-ray photoelectron spectroscopy, BET nitrogen adsorption, and UV-visible absorption spectroscopy. The conversion of the synthesized Cu2(OH)3Cl to sisal-like Cu(OH)2 was optically visualized and confirmed by corresponding SEM images, and an “etching-and-growing” mechanism was proposed. The results also show that the as-prepared CuO possesses a band gap of 2.27 eV and high specific surface area (75.8 m2/g), and its surface is highly rich in O. [ABSTRACT FROM AUTHOR]

Titania-grafted magnetic sporopollenin is synthesized by the liquid-phase deposition (LPD) technique, characterized by SEM, EDX, and nitrogen adsorption porosimetry, and used for the selective enrichment of phosphorylated peptides. The material is low cost because of easier availability of pollens and has rich surface chemistry which enables strong attachment of titania onto magnetic sporopollenin. The material shows higher selectivity of 1:1000 with β-casein spiked in BSA. Higher sensitivity of 10 fmol is recorded for phosphopeptides from standard β-casein digest. Twenty phosphorylated peptides are enriched from milk digest and four endogenous phosphopeptides from diluted human serum. The magnetic property of titania-coated magnetic sporopollenin facilitates the fast and effective isolation of phosphopeptides from complex mixtures through external magnet. The material is finally applied to tryptic digest of rat brain cell lysate for phosphopeptide enrichment where 2718 phosphopeptides are identified by using LC-MS/MS with C18 column. Titania-coated magnetic sporopollenin captures both mono-phosphorylated (2489) and multi-phosphorylated peptides (229) due to strong affinity of TiO2 with phosphates. TiO2-coated magnetic material also shows better enrichment efficiency in comparison to commercial TiO2. [ABSTRACT FROM AUTHOR]

Abstract Porous concrete has been proven as a promising template to prepare porous carbon monoliths because it can easily be formed to any geometric shape. To optimize the pore size distribution the template-assisted route can be combined with steps of the classical carbon activation such as the carbonization in the presence of zinc chloride. For the rational designing of such routes, profound knowledge of the pore-formation process is necessary. This is however complicated because the pore formation is the result of a complex interplay of different sub-processes. Here, we present approaches to estimate the contributions of these sub-processes to the overall porosity in a quantitative way. For that, the role of the template, the gasification reactions as well as the activating agent has been elucidated by elaborate analysis of nitrogen adsorption data. Graphical abstract Image 1 Highlights • Carbon pores result from the complex interplay of different sub-processes. • First approaches are presented to describe that interplay quantitatively. • The template contributes only little to the porosity of the carbon replica. • Gasification and activating agent, respectively, contribute nearly equally to the pore formation. [ABSTRACT FROM AUTHOR]

Abstract As a highly heterogeneous material, the porous structure of coal is usually described by fractal dimension, which generally can be obtained by gas adsorption, light scattering and image analysis methods. In this paper, the pore structure (pore volume and specific surface area) and adsorption performance (Langmuir volume and Langmuir pressure) of 12 different rank coal samples were investigated by liquid nitrogen adsorption experiment (LNA) and methane isotherm adsorption experiment. And the fractal characteristics of these coals were studied by three fractal dimensions D 1 , D 2 and D 3 acquired from LNA and small angle X-ray scattering (SAXS) and scanning electron microscopy (SEM), respectively. Results indicate that the adsorption pore volume and specific surface area show U-shaped evolutionary trends during the coalification process. The changes of pore volume and specific surface area are dominated by the mechanical compaction and dehydration effects before the second coalification jump (R o,max = 1.3%), while they are then mainly controlled by concomitant metamorphic pores until the fourth coalification jump (R o,max = 3.7%). Langmuir volume first increases and then reaches a steady value at the third coalification jump (R o,max = 2.5%) with the increasing coal rank, however, Langmuir pressure monotonously decreases during the whole coalification process. D 1 and D 2 exhibit a dramatically increase from R o,max = 0.6% to R o,max = 2.0% and then a slowly rise when R o,max increases from 2.0% to 3.5%, which is relevant to the changes of pore structure and macromolecule structure in coal. D 3 increases at a low speed first and then increases at a high speed with the increasing coal rank, which reflects the surface morphology of pores in coal. Fractal dimension D 1 , D 2 and D 3 can be used to depict the methane adsorption properties of coal in varying metamorphism degrees. Generally, D 2 is larger than D 1 , which is because N 2 adsorption can probe more macropores but SAXS can detect more micropores. Additionally, D 1, D 2 and D 3 are all negatively related to P L. Our investigations also confirm that SAXS may be more superior to character the adsorption capacity of coal according to its highest relativity. This work clarifies the intrinsic sense and difference for characterising the surface irregularity by various methods, and provides an understanding for the experimental means relating to adsorption pores. Highlights • The volume and specific surface area of adsorption pore display U-shaped evolutionary trends during coalification. • Langmuir volume and Langmuir pressure are related to the metamorphism effect of coal. • D 1 and D 2 demonstrate discrepancy versus coal rank. • SAXS may be more superior to character the adsorption capacity of coal. [ABSTRACT FROM AUTHOR]

Abstract Understanding the complexity and heterogeneity of pore structure can improve the comprehensive characterization for complex unconventional reservoirs and better exploit those resources. In this paper, multifractal analysis was conducted on low temperature N 2 adsorption and NMR T 2 distribution for the pore structure investigation in Middle Bakken formation in Williston Basin, USA. Results show that the averages of specific surface area, total pore volume, the average pore size of five N 2 adsorption samples are 3.31 m2/g, 0.008 cm3/g, and 19.57 nm, respectively. Six NMR T 2 distributions are bimodal and the signals of left dominant peaks are mainly distributed between 0.3 ms and 10 ms. The T 2 logarithmic mean value ranges from 2.18 ms to 2.95 ms with an average value of 2.57 ms. Both N 2 adsorption isotherms and T 2 distribution demonstrated the multifractal nature of different pore sizes. The key multifractal parameter, singularity strength range (Δ α) calculated from N 2 adsorption and T 2 distribution are respectively distributed in scopes of 0.72–1.54 and 1.63–2.89, indicating that the heterogeneity of pore space from T 2 distribution is stronger than that from N 2 adsorption. It was observed that the specific surface, micro pore volume, and average pore size are correlated well with Δ α. There are no any correlations between Δ α and porosity and T 2lm, but the cumulative porosity and width of right secondary peaks have an impact on the Δ α , which means that the heterogeneity difference between the two methods is attributed by larger pore and micro fractures. Highlights • The pore structure of Middle Bakken formation was studied by NMR T 2 distributions and low temperature N 2 adsorption. • The multifractal theory was applied to Middle Bakken formation for insights into pore structure and heterogeneity. • The effect of larger pore or micro-fracture on the heterogeneity of pore space was revealed. [ABSTRACT FROM AUTHOR]

Highlights • A polymer monolithic column was prepared by in-situ free radical polymerization. • The monolith was used for on-line enrichment and determination of β-sitosterol. • The maximum adsorption capacity was 12.69 mg/g, and the enrichment factor was 78. Abstract A novel monolithic column was prepared by in-situ free radical polymerization using N -methylolacrylamide (NMA) and N , N -diethylacrylamide (DEA) as co-monomers. The monolith was characterized by scanning electron microscopy (SEM) and its nitrogen adsorption-desorption isotherm, and it was used as a solid phase extraction (SPE) absorbent for the online enrichment of β-sitosterol by high performance liquid chromatography. The optimized method had good linearity, and the linear regression coefficient was 0.998. The limit of detection (LOD) and the limit of quantification (LOQ) were 0.006 mg/mL and 0.02 mg/mL, respectively. The interday and intraday accuracies were less than 7.28%. The spiked recoveries of β-sitosterol in the six plant oil were 90.96–103.56%. The maximum amount of β-sitosterol adsorbed on the monolithic column was 12.69 mg/g, and the enrichment factor of β-sitosterol was 78. The results showed that the monolith could be used as an online SPE absorbent for the determination of β-sitosterol in plant oil samples. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Altered nitrogen supply influenced arsenic concentrations of rice seedlings. • High nitrogen supply improved plants performance under control conditions. • In presence of arsenic, high nitrogen supply negatively affected growth of plants. • Low nitrogen supply, in presence of arsenic, increased plants tolerance to arsenic. Abstract In the present study, the effects of nitrogen supply (low nitrogen: LN and high nitrogen: HN) on As stress (25 μM) responses of rice seedlings were monitored for 7 d. The mean length of primary, adventitious and lateral roots and number of adventitious and lateral roots were significantly improved in LN+As, while further reduced in HN+As, as compared to As alone treatment at 7 d. The LN+As treatment resulted in significant decline in As (848 μg g−1 DW) than that in As alone treatment (1434 μg g−1 DW) in roots but no significant effect was seen in shoot. In contrast, HN+As treatment showed significant increase in shoot As (6.86 μg g-1 DW) as compared to As alone treatment (3.43 μg g-1 DW). The level of nitrate was increased in roots but declined in shoots in As alone treatment. Surprisingly, no improvement in nitrate level was seen in HN+As as compared to that in As alone treatment in both root and shoot. The expression analysis of nitrate transporters (NRT2;1, NRT2;3a, NRT2;4) showed significant differences in expression patterns in As, LN+As and HN+As treatments. In conclusion, nitrogen supply had profound influences on responses of rice plants to As. [ABSTRACT FROM AUTHOR]

Five surfaces with low Miller indices, including (001), (011), (111), (011¯) and (111¯), were generated by cleaving rhombohedral Ti2O3, and their surface energies were compared, which showed that (011) is cleaved more easily than others, followed by (001), (111), (011¯) and (111¯), so that we focused on (011), (001) and (111) surfaces. Phase diagram of stoichiometric, oxygen-deficient and nitrogen-substituted Ti2O3 (001) surfaces indicated that oxygen evaporation does not take place on stoichiometric surface, and oxygen-to-nitrogen substitution is not a indirect (two-step) process (oxygen evaporation, followed by nitrogen substitution into oxygen vacancies). It was proved from minimum energy path (MEP) and DFT total energy curves over MEP that the energy barrier of direct oxygen-to-nitrogen substitution process is lower than indirect process, and therefore, direct process is easier to take place than indirect process. [ABSTRACT FROM AUTHOR]

Abstract In this paper, a new method is proposed to quantify cation exchange capacity (CEC) in rocks with complex mineralogy and in the presence of multiple types of clay minerals by integrating nitrogen adsorption-desorption, nuclear magnetic resonance (NMR), and X-ray diffraction (XRD) measurements (including quantitative XRD). In the new method, a successive controlled nitrogen adsorption-desorption measurements as well as NMR measurements were performed on multiple samples from the same rock type. Then, an inversion algorithm was introduced to estimate surface area and volume of hydration water of each mineral, which were used as inputs to our recently-developed novel physics-based CEC estimation workflow. The CEC estimates obtained from the new method were compared against those from the ammonium acetate method and inductively coupled plasma mass spectrometry (ICP-MS) measurements in synthetic and actual powdered shaly sand rock samples. The results showed that the CEC estimates from the two methods were in good agreement, with less than 4 meq/100 g difference (i.e., average relative error of less than 23%). The experimental results demonstrated reliability of the proposed method for CEC quantification in clay-rich formations with complex lithology in the presence of multiple types of clay minerals. [ABSTRACT FROM AUTHOR]

Graphical abstract Construction of hierarchical porous Al-KIL-2 via kinetic regulation. Highlights • Hierarchical aluminosilicates were synthesized via kinetic regulation method. • Hierarchical Al-KIL-2 possessed well distributed bimodal mesopores. • Composition of framework Al and non-framework Al was analyzed by XPS. • Adjustable porous and acidic properties can face to adsorption of various molecules. Abstract Novel hierarchical Al-KIL-2 aluminosilicates with bimodal mesoporous distribution were successfully synthesized via a feasible and cost-effective kinetic regulation method. The molar ratio of Si/Al, the kinetics of Al-Si polyanions growth and its following oriented-attachment on KIL-2 matrix were regulated aiming at various porous and acidic properties. The hierarchical Al-KIL-2 samples were characterized, and their adsorption capacities were tested by adsorptive denitrogenation for model fuels containing pyridine and quinoline. It was revealed that the branching epitaxial growth behavior originating from Al-zoning on KIL-2 matrix contributed to fabrication of the hierarchical porous structures. In addition, introduction of Al endowed KIL-2 with rich Lewis acid sites for the adsorption of basic contaminants. Hierarchical Al-KIL-2 obtained considerable adsorption efficiencies of pyridine and quinoline, the regularities of which relied on the appropriate kinetic regulation conditions during materials synthesis. The adsorption isotherms and adsorption thermodynamics research essentially presented the feature of this adsorptive denitrogenation system over hierarchical Al-KIL-2 for its potential industrial applications. [ABSTRACT FROM AUTHOR]

Abstract Porosity and pore size distribution (PSD) are critical reservoir parameters. Pore surface area, pore volume, PSD, and porosity were measured using subcritical nitrogen (N 2) adsorption, and helium porosimetry. A suite of 17 samples were collected from 4 wells in Pennsylvania and West Virginia to analyze the evolution of porosity with increasing thermal maturity in Middle Devonian shales of the Appalachian Basin. The thermal maturity of the tested samples covers a wide range in the hydrocarbon generation sequence from wet gas/condensate zone (vitrinite reflectance (R o) = 1.16%) to post-mature zone (R o = 2.79%). Shale samples from the Marcellus Shale and Mahantango Formation used in this study have total organic carbon contents from 0.41 to 7.88 wt%. Results indicate that total organic carbon (TOC) has the strongest effect on porosity and pore structure. The presence of organic matter in shale strongly enhances the storage capacity by increasing the specific surface area and pore volume, which represents sorption storage capacity and free-gas storage capacity. Differences in porosity and pore structure have a complex relationship to thermal maturity, micro texture, mineralogy, clay content, and TOC. [ABSTRACT FROM AUTHOR]

Abstract The influence of porous structure and addition of citric acid on the formation of ceria particles inside the SBA-15 pores is studied using nitrogen adsorption-desorption at −196 °C, XRD, UV-visible spectroscopy, TEM and TPR-H 2 methods. The use of pores of SBA-15 as nanoreactors provides the formation of CeO 2 nanoparticles with sizes below 6 nm. According to XRD and TEM results, the addition of citric acid during the impregnation allows obtaining the CeO 2 particles with sizes about 3 nm, while the agglomerates of large СеО 2 particles are formed on the surface of the SBA-15, when citric acid is not added. Small sizes of ceria particles (3 nm) cause an enhanced reducibility (TPR-H 2), high defectiveness of the particles and red shift in the UV-vis adsorption spectra. These properties may improve the catalytic and photocatalytic activity of the CeO 2 /SBA-15-based catalysts in deep and selective oxidation of organic compounds. Graphical abstract Image 1 Highlights • Pores of SBA-15 as nanoreactors provide formation of CeO 2 NPs with sizes below 6 nm. • Addition of citric acid during impregnation provides formation of small CeO 2 NPs (<3 nm). • Small sizes of CeO 2 NPs lead to increased reducibility and red shift of UV-vis adsorption. [ABSTRACT FROM AUTHOR]

Highlights • The fundamental and first overtone bands of N 2 are studied by CRDS and OFCEAS. • High sensitivity measurements are performed near 2492 and 4720 cm−1. • The collision-induced absorption (CIA) is measured at sub-atmospheric pressure. • The very weak 2–0 S(10) and S(11) are measured for the first time in the laboratory. • Comparison to literature, in particular to the HITRAN database, is discussed. Abstract Highly sensitive cavity enhanced laser techniques are used for accurate measurements of the absorption of dinitrogen (N 2) at two spectral points of the fundamental and first overtone bands. Spectra of pure N 2 and of a N 2 /O 2 mixture were recorded near 2491 and 4720 cm−1 by Optical Feedback Cavity Enhanced Absorption Spectroscopy (OF-CEAS) and Cavity Ring Down Spectroscopy (CRDS), respectively. The noise level of the OF-CEAS and CRDS spectra corresponds to a minimum detectable absorption, α min , of about 10-9 and 10-11 cm−1, respectively. Measurements involve both the N 2 collision-induced absorption (CIA) bands and the very weak 2–0 S (10) and S (11) electric quadrupolar transitions. Accurate CIA binary coefficients, B N 2 − N 2 and B N 2 − O 2 , are derived from the pressure-squared dependence of the baseline level of the spectra recorded at pressures below 1 atm. These CIA values are compared to previous determinations from high pressure spectra (up to 90 atm) and to recent classical molecular dynamics simulations (CMDS). An overall good agreement is obtained although a significant deviation is observed for the first overtone CIA near 4720 cm−1. The line position and intensity (on the order of a few 10−30 cm/molecule) of the 2–0 S (10) and S (11) electric quadrupolar transitions are determined experimentally for the first time and compared to theoretical values provided in the HITRAN2016 database. Graphical abstract Image, graphical abstract [ABSTRACT FROM AUTHOR]

Abstract Based on a mono hydrogen-passivated zigzag SiC nanoribbon with width 4, we construct a heterojunction through different substitutional impurities. The left part of the heterojunction is boron-doped at the Si-edge of zigzag SiC nanoribbon, and the right part is nitrogen-doped at the C-edge. Our results show that boron and nitrogen doped zigzag SiC nanoribbons exhibit half-metallic features at ferromagnetic state, which provides the possibility to design spin nanodevices. By performing first-principle quantum transport calculations, spin-dependent transport properties in different magnetic configurations are studied. Current-voltage curves show perfect spin-filtering and negative differential resistance effects when the spin orientations of the two electrodes are opposite. In the parallel magnetization configuration of two electrodes, a strong rectifying behavior is observed and the maximum rectifying ratio reaches the order of 109. Through detailed analysis of two electrodes' band structures along with the transmission spectra, the interesting transport behaviors can be understood. Besides, the Bloch states of spin-polarized bands crossing the Fermi level can help us to understand the appearance of the negative differential resistance effect. Highlights • Spin-dependent transport in a zigzag silicon carbon nanoribbon heterojunction with boron and nitrogen impurities is studied. • In parallel magnetic configuration, strong rectifying behavior is observed and can be used as a diode. • In antiparallel magnetic configuration, the I V curves display spin filtering and NDR effects. • The half-metallic character and localized edge states give us a good starting point to design spin nanodevices. [ABSTRACT FROM AUTHOR]

Graphical abstract Three palladium(II) complexes with imidazole derivatives, 1,2-dimethylimidazole (1), benzimidazole (2) and 2-phenylimidazole (3) were prepared and crystal structures for two of them (1 and 2) were determined by X-ray crystallography. The palladium(II) ion in both complexes is bound to two nitrogen atoms of imidazoles and two chloride ions at trans positions, adopting a nearly regular square planar geometry. The complexes were screened for various biological activities including antimicrobial, antioxidant and antidiabetic properties. The complexes exhibited moderate antimicrobial activities but their antidiabetic effects with respect to the standard are significant. Abstract Three palladium(II) complexes (1 – 3) with imidazole derivatives; 1,2-dimethylimidazole, benzimidazole and 2-phenylimidazole were prepared and characterized by thermal and spectral analyses. The crystal structures for two of them (1 and 2) were determined by X-ray crystallography. The palladium(II) ion in both complexes is bound to two nitrogen atoms of imidazoles and two chloride ions at trans positions, adopting a nearly regular square planar geometry. The complexes were screened for various biological activities including antimicrobial, antioxidant and antidiabetic properties. The biological activities of the complexes are more effective as compared to the respective ligands. The complexes exhibited moderate antimicrobial activities but they were not good as antioxidants. However, their antidiabetic effects with respect to the standard are significant. [ABSTRACT FROM AUTHOR]

Abstract A series of natural zeolites with different compositions were modified by formation of hydrated aluminium oxide onto the zeolite structure after NaOH treatment of the natural zeolites. Natural and modified zeolites were characterized by XRD, SEM, N 2 adsorption-desorption, FTIR, zeta potential and temperature-programmed desorption of ammonia (NH 3 -TPD). The treatment with NaOH and then aluminium loading significantly alter zeolite characteristics depending on zeolite composition and structure. The treatment with NaOH causes significant desilication and partial dealumination of the zeolites irrespective of their compositions. The presence of quartz and feldspar phases in the zeolites increases their stability towards alkali treatment. Aluminium introduction into the zeolites treated with NaOH leads to reorganisation of zeolite structure and surface characteristics. The introduction amount of aluminium is strongly related with zeolite composition that aluminium oxide phase is detected on zeolites undergone highly desilication with NaOH treatment. Both alkali treatment and aluminium loading dramatically alter distribution of acid sites in the zeolites that while alkali treatment increases mostly strong acid sites of zeolites, aluminium loading enhances weak and medium acid sites. Enhanced aluminium content of zeolites improved its manganese adsorption capacity depending on their composition. Graphical abstract Unlabelled Image Highlights • The treatment with NaOH and then aluminium loading significantly alter zeolite characteristics. • The introduction amount of aluminium into zeolites is strongly related with zeolite composition. • Aluminium oxide phase is mostly formed on highly desilicated zeolites. • Aluminium loading mostly enhances weak and medium acid sites of zeolites. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The silica powder can be activated at short time, 15 min by planetary ball mill. • The powders are pulverized and new active surfaces are formed at longer time. • The ratio of ball/powder is the important factor for the effective activation. Abstract "Non-firing" ceramics have recently attracted much attention in recent years because many functional materials can be achieved by this method without the aid of sintering process. Amorphous silica powder was mechanically treated by a planetary ball mill system, by which the surface of powders was activated and simultaneously particle size reduced extensively. Surface of powders with different milling conditions was investigated by scanning electron microscopy (SEM) and nitrogen adsorption isotherm. The surface activity of raw and treated silica powders was measured based on the water adsorbed volume on the powder surface. Results showed that the powder surface was activated, and the silica powders were pulverized as an effect of ball milling. At milling times as short as 15 min, the powder was rubbed against balls, and the friction between particle/ball breaks the bonds of functional groups like Si O Si on the surface of particles. For longer milling times, powders were pulverized and more new active surfaces were formed. [ABSTRACT FROM AUTHOR]

Abstract Low-field nuclear magnetic resonance (LF-NMR), high-speed centrifuge and low-pressure nitrogen adsorption (LPNA) experiments were conducted on shale samples from the Lower Silurian Longmaxi Formation to measure pore-throat parameters of the shale reservoir. We measured bound water saturation, helium porosity, bulk density, specific surface area, and pore-size distribution to evaluate reservoir quality. The thickness of the bound water film was calculated based on the equation established from these parameters, showing that its thickness ranges from 1.07 nm to 2.73 nm, with a mean of 1.72 nm. In addition, Grand Canonical Monte Carlo (GCMC) and molecular dynamics (MD) simulations were carried out to estimate the methane adsorption capacity and the number of the adsorbed layers in pores with different sizes at the given temperature and pressure (393.15 K, 65 MPa). The simulation results demonstrate that methane is unanimously adsorbed into pores <1.52 nm in diameter. Shale gas was present in both free and adsorbed states when the pore size was larger than 1.52 nm, and two layers were adsorbed on each pore wall. By combining the thicknesses of bound water film and adsorbed layers, the pore-throat lower limit for the shale gas reservoir was calculated to be about 4.96 nm. Highlights • Experiments and molecular simulation were used to determine the lower threshold of pore diameter in shale reservoir. • Based on NMR and LPNA experiments, the bound water film was determined to be 1.72 nm. • Reliable force field was adopted on both OM and illite during GCMC simulation to determine the methane adsorption layers. • The lower threshold pore diameter for shale reservoir was 4.96 nm. [ABSTRACT FROM AUTHOR]

Highlights • An Ag NPs-coated monolithic column has been fabricated for in-tube SPME. • The Ag+-like affinity interaction has been utilized for the effective extraction of MUFAMEs. • A simple in-tube SPME-Ag+-HPLC method has been proposed for the detection of MUFAMEs. Abstract Based on our developed sodium hyaluronate-functionalized urea-formaldehyde (HA-UF) monolith, a silver nanoparticles-coated monolithic column has been fabricated via the interaction between silver nanoparticles (Ag NPs) and HA. The successful coating of Ag NPs on the parent monolith was proven by SEM, EDAX, UV–vis spectrum and XPS. Nitrogen adsorption desorption isotherms and Barret-Joyner-Halenda (BJH) pore size distributions of the parent and resultant monolith were also performed. Due to the Ag+-like affinity interaction caused by the contact of unsaturated compounds and Ag NPs, the Ag NPs-coated monolith showed satisfactory extraction efficiency towards these compounds, and was applied for in-tube solid-phase microextraction (SPME) of monounsaturated fatty acid methyl esters (MUFAMEs). Several factors for in-tube SPME, such as ACN percentage in the sampling solution, elution volume, sampling and elution flow rate, were investigated with respect to the extraction efficiency of model MUFAMEs. Under the optimized SPME conditions, a simple in tube SPME-Ag+-HPLC method for detection of model MUFAMEs has been proposed, the limits of detection (LODs) were less than 5.2 μg/kg, and the recoveries of spiked French fry samples were ranged from 86.6% to 96.1% with relative standard deviations (RSDs) less than 5.2%. This study provided an Ag NPs-coated monolith with good reproducibility and repeatable extraction performance, and developed an efficient method for in-tube SPME of MUFAMEs in practical food samples. [ABSTRACT FROM AUTHOR]

Abstract Carbon cloth supported lamellar nickel-cobalt-molybdenum ternary phosphide (donated as NCMP) nanoarrays are prepared by a simple method including a hydrothermal and subsequent phosphorization process. The NCMP nanosheets are grown vertically on carbon cloth fibers (CC) to form a three-dimensional (3D) thin-wall cell structure with open pores (donated as NCMP@CC), which can be directly acted as working electrode without other binders or conductive additions, and achieves a specific capacitance as high as 433 F g−1 at a current density of 1 A g−1. Meanwhile, in order to match the capacitive behaviors of NCMP@CC in the two-electrode systems, hierarchically porous, nitrogen-doped, and interconnected carbon nanosheets (donated as HPN-CNS) are also prepared from agaric through a one-step method. An asymmetric supercapacitor device (ASC) is assembled successfully by employing the self-supported thin-wall cell structure NCMP@CC as positive electrode and the HPN-CNS as the negative electrodes, respectively. More importantly, the device exhibits not only high energy density of 43.83 W h kg−1 along with power density of 0.89 kW kg−1, but also an excellent cycle stability (82.4% after 10 000 cycles) under a cell voltage of 1.8 V. Graphical abstract Image 1 Highlights • 3D thin-wall cell structure Ni-Co-Mo ternary phosphide composites were prepared. • Hierarchically porous and nitrogen-doped carbon nanosheets were prepared from agaric. • NCMP@CC//HPN-CNS ASC device was assembled. • The NCMP@CC//HPN-CNS device showed high energy and power density. [ABSTRACT FROM AUTHOR]

Abstract Nanocrystalline magnesium ferrite is synthesized by high-energy ball milling of α-Fe 2 O 3 and MgO powders and annealed at 700, 800 and 900 °C temperatures. The Prolonged mechanical milling process has reduced the average crystallite size of MgFe 2 O 4 to the nanometer range as confirmed by the X-ray diffraction analysis. Along with MgFe 2 O 4 phases of α-Fe 2 O 3 and metallic Fe were highlighted by the Rietveld XRD refinements. The scanning electron microscopy micrographs of as-milled MgO-Fe 2 O 3 showed cauliflower-like nanostructure with narrower size distribution (≈75 nm). Furthermore, nitrogen adsorption BET analysis demonstrated flatter rather than cylindrical shaped pores with an average pore diameter in the range 24.7–66.3 nm and decreased surface area from 13.45 to 2.23 m2/g, as a function of annealing temperature. This is consistent with the increased crystallite size values obtained from XRD analysis. The magnetic study indicated a ferromagnetic behavior with low coercivity (68.68 Oe), remanence (0.840 emu/g) and saturation magnetization of 6.517 emu/g. The variation of magnetization as a function of temperature signified cations redistribution within the spinel phase MgFe 2 O 4. The as-obtained nanopowders were tested for heavy metal removal from aqueous solutions where the data revealed improved ions removal by low temperature annealed nanoparticles especially for Ni+2 and Cd+2 indicating their potential for contaminants removal. [ABSTRACT FROM AUTHOR]

Highlights • Reusability of SrO used in transesterification is enhanced by MIL-100(Fe) derivate. • Catalytic activity of MM-SrO and ST-SrO is mainly affected by the strong basicity. • MM method is suitable to prepare catalyst of SrO supported by MIL-100(Fe) derivate. • MM-SrO precursor exhibits the multistage character during the thermal activation. Abstract Strontium oxide (SrO) is restricted by poor reusability and pore structure in catalyzing transesterification for biodiesel production. To address this problem, metal organic frameworks is employed as a carrier to support strontium carbonate by mechanical mixing method (MM) and in situ titration method (ST), and then calcined under inert atmosphere to obtain the catalyst of MM–SrO and ST–SrO. As a comparison, the reusability of pure SrO is compared and the homogeneous contribution of leached active sites for ST–SrO and MM–SrO are also assessed. The catalysts are characterized by TG, XRD, FTIR, EDS, Hammett indicator titration, nitrogen adsorption–desorption, and VSM. From the catalyst reusability, MM–SrO exhibits the excellent performance, where the maximum conversion of 96.19% is achieved at molar ratio of methanol to oil 12, catalyst addition 8 wt% (refer to oil), reaction temperature 65 °C within 30 min. And the conversion of 82.49% is still obtained at the third cycle, which could be easily separated from the mixture by external magnetic field after each cycle as well. In order to optimize the activation condition and investigate MM–SrO deeply, thermal characteristics of its corresponding precursor are further evaluated, where the TG experiments are conducted at heating rate of 20, 30, and 40 °C/min. and kinetic parameters are calculated through model–free method and Avrami theory, respectively. [ABSTRACT FROM AUTHOR]

Abstract The causes of atypical nitrogen adsorption isotherm features of commercial magnesium stearate grades have been investigated through a combination of alternative adsorbates and variation of analytical conditions. Atypical features have previously been identified as having poor linearity of adsorption isotherms at relative pressures applied to the calculation of BET surface area and low pressure hysteresis between adsorption and desorption branches. These features are most pronounced for di-hydrated MgSt and are absent for the anhydrous form: the presence of hydrated water causing atypical features. The possible interaction between hydrated water molecules and nitrogen via the nitrogen quadrupole is investigated through application of non-polar adsorbates; argon and krypton. Low pressure hysteresis is investigated through alteration of equilibration conditions and through truncating adsorption isotherms to successively lower maximum relative pressures before commencing desorption. It is found that atypical gas sorption isotherms are not limited to nitrogen. The effects of these conditions on adsorption and desorption volumes are discussed and a model for the origin of atypical isotherm features is presented. The difference in gas sorption behaviour of anhydrous, mono-hydrated and di-hydrated magnesium stearate is discussed and ultimately the consequences on the calculation of BET surface area is considered. Graphical abstract Unlabelled Image Highlights • Study of atypical adsorption isotherms of Mg stearate in varying hydration states. • N 2 , Kr and Ar used to investigate BET surface area and isotherm hysteresis. • Possible causes of atypical BET surface area and isotherm data are discussed. • Structural swelling of magnesium stearate and adsorptive entrapment is shown. • BET surface area shown to be over-estimated particularly with the di-hydrate. [ABSTRACT FROM AUTHOR]

Abstract Silver, as a cheaper and good conductivity noble metal, has successfully been decorated on SnO 2 nanoparticles to structure the Ag-SnO 2 composites by a facile hydrothermal and in situ reduction method. The difference of structure and properties between SnO 2 and composite was characterized by XRD, FESEM, elemental mapping, UV–vis spectroscopy, BET and XPS surface analysis. The sensing performance of SnO 2 and composite to formaldehyde were also examined. The composite of 3.7 wt% Ag decorated SnO 2 not only exhibits the high response to 10 ppm of formaldehyde but also has better stability and selectivity at an operating temperature of 125 °C. Moreover, the detection limit of the composite was determined to be 0.53 ppm, which is lower than that of pure SnO 2 nanoparticles. The response mechanism of the composite to formaldehyde was also discussed in detail, which is attributed to the catalytic effect and the spillover effect of Ag nanoparticles. Graphical abstract The response of the 3.7 wt% Ag-SnO 2 composite exhibits response 7 times higher than pristine SnO 2 to 10 ppm formaldehyde at 125 °C and good selectivity to other frequently encountered VOCs in indoor environments, and also has good stability, so, the composite is a promising material to detect trace harmful VOCs over other frequently encountered in indoor environments. Image 1 Highlights • The response of Ag-SnO 2 is 7 times higher than that of SnO 2 to 10 ppm HCOH. • The operating temperature of composite is reduced from 150 °C to 125 °C. • The 3.8 wt% Ag decorated composite also has excellent selectivity and stability. • Improving sensing properties is ascribed to the spillover and catalytic effects of Ag. [ABSTRACT FROM AUTHOR]

Abstract In this study, nanoflaky maghemite (γ-Fe 2 O 3) was successfully prepared by heating of synthesized lepidocrocite (γ-FeO(OH)). Once maghemite obtained, the electrochemical performance of nanoflaky maghemite, as an anode for Li-ion batteries, was investigated. Synthesis of lepidocrocite was optimized by adjusting the heating time and ratio of ethylene glycol (EG) to water in solution. The results revealed that with equal ratio of EG to water, the obtained phase was crystalline lepidocrocite whereas in other ratios lepidocrocite was not the only emerged phase. Field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) results revealed that increasing heating time has no effect on morphology. This increment only led to the slight crystallite growth and agglomeration of precipitation. The optimized lepidocrocite were heated at 230 °C for 2 h to form maghemite, which was confirmed by using XRD. FESEM, high-resolution transmission electron microscopy, and nitrogen adsorption-desorption results disclosed that the particles have flaky morphology with thickness of less than 10 nm and surface area of 105 m2 g−1. Cyclic voltammetry results of anode body (prepared using nanoflaky maghemite) demonstrated reversible formation pathway of iron and lithium oxide through discharging and charging. Moreover, galvanostatic charge–discharge cycling showed a reversible capacity of about 480 mAh g−1 after 50 cycles at current density of 500 mA g−1. Good cyclability, and capacity retention of the anode is due to the nananometric size and flaky shape of the maghemite particles. These particles' shape made it easier for them to expand and contract in thickness direction with minimized destructions imposed. [ABSTRACT FROM AUTHOR]

Fe(II)-montmorillonites (Fe(II)-MMTs) were prepared by mixing solutions of Fe(II) and montmorillonite at pH 3.5. Two different Fe(II)-MMTs were prepared and the ferrous iron contents were 40 mg/L and 80 mg/L. All samples were characterized by XRD, FT-IR, TGA, DSC, and nitrogen adsorption. By nitrogen adsorption, the pore size can be obtained in the pore diameter curve with average pore widths of 6.67 nm, 9.96 nm, and 17.07 nm, respectively. The removal rate of phosphate increased rapidly during the first 40 min, in which Fe(II)-MMT (1) and Fe(II)-MMT (2) were stronger adsorption systems than MMT. The maximum adsorption was 48.38 mg/g at pH 2.0. The kinetics of phosphate adsorption were better described using pseudo-second-order models (R2 : 0.997, 0.999, 1.000) than pseudo-first-order (R2 : 0.933, 0.900, 0.760). R2 is the determinable statistic coefficient that measures the goodness of fit. If the R2 value is closer to one, the fitting degree of the regression line is better. By the thermodynamic analyses, we obtained the ΔG°and ΔH°of samples at 298 °C, 303 °C, and 310 °C. The adsorption isotherms also better fitted a Langmuir model in which the process was nonspontaneous and exothermic. [ABSTRACT FROM AUTHOR]

The products of mechanosynthesis in the systems "superstoichiometric fluorocarbon nanomaterial CF1.2-thermally expanded graphite" are studied using X-ray photoelectron spectroscopy and low-temperature nitrogen adsorption to identify texture characteristics. A correlation is revealed between the conductivity of the composites and functional composition of their surface layers. The obtained results are explained by the fact that mechanosynthesis products contain mesoporous carbon-fluorocarbon nanocomposites consisting of micro- and nanoparticles CF1+x coated by an outer nanolayer sp2-C-sp3-C-F. [ABSTRACT FROM AUTHOR]

Diatom biosilica are highly complex inorganic/organic hybrid materials. To get deeper insights on their structure at a molecular level, model systems that mimic the complex natural compounds were synthesized and characterized. A simple and efficient peptide immobilization strategy was developed, which uses a well‐ordered porous silica material as a support and commercially available Fmoc‐amino acids, similar to the known solid‐phase peptide synthesis. As an example, Fmoc‐glycine and Fmoc‐phenylalanine are immobilized on the silica support. The success of functionalization was investigated by 13C CP MAS and 29Si CP MAS solid‐state NMR. Thermogravimetric analysis (TGA) and elemental analysis (EA) were performed to quantify the functionalization. Changes of the specific surface area, pore volume, and pore diameters in all modification steps were studied by Brunauer–Emmett–Teller based nitrogen adsorption–desorption measurements (BET). The combination of the analytical methods provided high grafting densities of 2.1±0.2 molecules/nm2 on the surface. Furthermore, they allowed for monitoring chemical changes on the pore surface and changes of the pore properties of the material during the different functionalization steps. This universal approach is suitable for the selective synthesis of pores with tunable surface‐peptide functionalization, with applications to the synthesis of a big variety of silica–peptide model systems, which in the future may lead to a deeper understanding of complex biological systems. A protocol for direct solid‐phase peptide synthesis inside silica pores has been developed and its success and efficacy monitored by solid‐state NMR spectroscopy. [ABSTRACT FROM AUTHOR]

In situ sediment remediation using modified clay has become increasingly popular in aquatic ecosystem management. In this study, two modified clays, Phoslock® and modified zeolite, were used together to co-manage nitrogen and phosphorus loading from a polluted river sediment and intermittent aeration was used as an aid for this remediation. After 120 days of core incubation, results indicated that the two clays alone cannot effectively control all the total and soluble nitrogen and phosphorus concentrations in the overlying water all the time. However, the combined use of clays with intermittent aeration can effectively reduce the nutrient concentrations throughout the experiment. Sediment phosphate flux can be largely inhibited solely by clays or when combined with aeration. Meanwhile, the ammonium flux can only be inhibited effectively for 60 days and is not statically different from control after 120 days. Surprisingly, intensive bioturbation can create a vertical movement of the applied clays in sediment with time, which enhances the phosphorus and nitrogen retention capacity of the subsurface sediment. Phosphorus fractionation analysis indicated that around 50% of mobile phosphorus was reduced in a 4–6 cm sediment layer after 120 days. In contrast, the extractable ammonium and nitrate content in treated sediment increased 2–3 times in this layer. The short-term bioturbation experiment confirmed that bioturbation did not have a large effect on P control efficiency of the clay-treated sediment. Conversely, bioturbation can enhance ammonium release from sediment and the following gradual burial effect can have a negative effect on nitrogen removal from overlying water over time. These results indicate that intensive bioturbation should be considered in polluted river sediment remediation. [ABSTRACT FROM AUTHOR]

The quantitative characterization of pore size distribution in low-rank coal reservoirs is significant for the determination of gas content and evaluation of coalbed methane (CBM) development potential. However, each test method can only detect the limited pore size range and the measured data cannot be used comprehensively. In this paper, a continuous distribution model of pore space was constructed for coal reservoirs based on the measured data of mercury intrusion porosimetry (MIP) and low-temperature nitrogen adsorption (LTNA) experiments. This model can overcome the above weakness and obtain the complete pore size distribution from nanopores to microfractures. Through verifying and adjusting the whole structure model, it can be used to refine the gas storage space of low-rank coals. The simulation results show that the pore size distribution differs greatly for coal samples from different regions or even from the same region, which is consistent with the general feature of strong heterogeneity of coal reservoirs in China. Even though pores smaller than 100 nm are still dominate in low-rank coal reservoir, the average volume of pores larger than 100 nm can reach 37%, which is obviously higher than that in medium-high rank coal reservoir and provides effective space for the storage of large amount of free gas. With the increase of coalification degree, the percentage of pores smaller than 100 nm presents an increasing trend. [ABSTRACT FROM AUTHOR]

A series of silica surface-capped with hexamethyldisilazane (denoted as H-SiO2) were prepared by liquid-phase in-situ surface-modification method. The as-obtained H-SiO2 was incorporated into acrylic amino (AA) baking paint to obtain AA/H-SiO2 composite extinction paints and/or coatings. N2 adsorption–desorption tests were conducted to determine the specific surface area as well as pore size and pore volume of H-SiO2. Moreover, the effects of H-SiO2 matting agents on the physical properties of AA paint as well as the gloss and transmittance of AA-based composite extinction coatings were investigated. Results show that H-SiO2 matting agents possess a large specific surface area and pore volume than previously reported silica obtained by liquid-phase method. Besides, they have better dispersibility in AA baking paint than the unmodified silica. Particularly, H-SiO2 with a silica particle size of 6.7 μ m and the dosage of 4% (mass fraction) provides an extinction rate of 95.2% and a transmittance of 79.3% for the AA-based composite extinction coating, showing advantages over OK520, a conventional silica matting agent. Along with the increase in the silica particle size, H-SiO2 matting agents cause a certain degree of increase in the viscosity of AA paint as well as a noticeable decrease in the gloss of the AA-based composite extinction coating, but they have insignificant effects on the hardness and adhesion to substrate of the AA-based composite coatings. This means that H-SiO2 matting agents could be well applicable to preparing low-viscosity and low-gloss AA-based matte coatings. Large pore volume H-SiO2 was prepared by liquid-phase in-situ surface-modification method. The as-obtained H-SiO2 was incorporated into acrylic amino (denoted as AA) baking paint to obtain AA/H-SiO2 composite extinction coatings. The results showed that H-SiO2 displays good dispersibility in AA/H-SiO2 composite coatings while the viscosity of coatings only slightly increased. Particularly, 4 wt% H-SiO2 can provide excellent extinction property. This indicated that the prepared silica could be well applicable to preparing low-viscosity and low-gloss AA-based matte coatings. [ABSTRACT FROM AUTHOR]

Micropores of shale are significant to the gas content and production potential of shale, which has been verified in the research of marine shale gas; while, few studies have been conducted on lacustrine shales. This study collected 42 samples from three wells in the Late Cretaceous Qingshankou Formation of the southern Songliao Basin, NE China, and investigated these samples by the focused ion beam‐scanning electron microscope (FIB–SEM) and nitrogen adsorption analysis techniques. Four types of micropores were identified in the samples, i.e., intergranular pore, intracellular pore, organic matter pore and microfracture. The pore structure type is characterized by open slit pores and "ink type" pores which are mainly 1.5–5 nm in diameter with mesopores as the main pores. The mesopores account for 74.01% of the pore volume and 54.68% of the pore surface area. Compared with the lacustrine shales from the Triassic Yanchang Formation in the Ordos Basin and Xujiahe Formation in the Sichuan Basin, the intergranular clay mineral interlayer pores are considered to be the main reservoir space for shale gas storage in the study area, followed by intraparticle pores, organic matter pores and microfractures. Maturity and micropore are the key controlling factors which affect the shale gas content of the Qingshankou Formation in southern Songliao Basin. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Controlled hydro-compaction of nanosilica appropriately changes the textural characteristics of the material. • Primary nanoparticles remain practically the same after hydro-compaction of nanosilica. • Activity and mobility of nanoparticles in compacted nanosilica renew after additional wetting. Abstract The morphological and textural characteristics of hydro-compacted nanosilicas (wetted by various water amounts in the range of h cp = 0.3–5.0 g per gram of dry silica, and then dried) were analyzed using low-temperature 1H NMR spectroscopy, SAXS, SEM, TEM, IR spectroscopy, and nitrogen adsorption methods. The results of the hydro-compaction of nanosilica A-300 depend strongly on the h cp value, which can be varied to control reorganization of secondary and ternary structures formed by nanoparticles. The compaction is accompanied by non-monotonic changes in the textural characteristics; however, the nanoparticles per se are practically not affected by the treatment. At h cp ≤ 1 g/g, the reorganization of secondary/ternary structures does not lead to diminution of the specific surface area (S BET); however, at h cp ≥ 1.5 g/g, the S BET value decreases, but the pore volume increases despite the empty volume of the powder decreases from 21.8 cm3/g for initial A-300 (bulk density ρ b = 0.045 g/cm3) to 3.45 cm3/g on compaction at h cp = 4.5 g/g (ρ b = 0.256 g/cm3). The structural reorganization of hydro-compacted powders is possible after addition of new water amount. This suggests that the chemical bonds between neighboring nanoparticles do not practically form upon the hydro-compaction. Thus, hydro-compacted nanosilica can lose a dust-forming property but remains active with respect to nanoparticles mobility and possibility of reorganization of the secondary structures with nanoparticles. [ABSTRACT FROM AUTHOR]

Mesoporous chabazite zeolites were prepared by using the cationic polymer polydiallyldimethylammonium chloride (PDADMAC) as template for mesopores and N,N,N-trimethyl-1-adamantammonium hydroxide as structure directing agent for the chabazite framework. The prepared zeolites had large surface areas and significant mesopore volumes that increased with high PDADMAC loading. Nitrogen sorption isotherms of chabazite zeolites with low loadings of PDADMAC (0.8–2.3 wt.%) displayed a composite of Type I and II with a broad H4 hysteresis loop at p/p o =0.8–1.0. At a high polymer loading (3.1 wt.%) the resulting zeolite displayed the Type IV sorption isotherm and H3 hysteresis. The chabazite zeolites prepared with 0.8–2.3 wt.% polymer had exponentially decaying mesopore size distribution curves ranging from 2 to 30 nm centred around 4–5 nm. A polymer loading of 3.1 wt.% gave a zeolite with a multimodal meso- and macropore size distribution curve ranging from 2 to 140 nm. Adjusting the synthesis gel composition made it possible to prepare mesoporous chabazite zeolites with PDADMAC loadings up to 3.1 wt.% at Si/Al = 20–70. [ABSTRACT FROM AUTHOR]

Commercial lipase from Burkholderia cepacia is immobilized on functionalized multi-walled carbon nanotubes (MWNT-COOH and MWNT-OH) provided by a physical adsorption. The immobilization processes for the carbon nanotubes are defined using immobilization time (0-30 min) and distinct adsorbent:adsorbate ratios (1:4, 1:7, and 1:10) with lipase loading of 100, 175, and 250 mg, respectively. The characterization of the immobilized preparations, the free lipase, and the pure nanotubes (MWNT-COOH and MWNT-OH) indicate that the lipase adsorption is increased. Thermogravimetric analysis, differential scanning calorimetry, and scanning electron microscopy are used. The specific surface area, pore volumes, and average pore diameters are determined by nitrogen adsorption-desorption isotherms. For the pure lipase, in the range between 40 and 300 °C, the micrograph is acquired. Experimental results clearly show an effective lipase adsorption in a lower period of time (5 min) in MWNT-COOH and MWNT-OH as well as a decrease in the surface area (98.30-45.9(86) ± 2.5 and 97.61-37.71 ± 3.3(7) m2 g−1) and the pore volume (0.48-0.25 ± 0.01 and 0.39-0.24 ± 0.05 cm3 g−1), indicating that functionalized multi-walled carbon nanotubes can be successfully used as enzyme support. [ABSTRACT FROM AUTHOR]

Nitrogen is of key importance to sustain modern agriculture but how to accurately quantify the loss forms of fertilizer-derived nitrogen has been a challenge for bare loessial soil. We employ 30 simulated rainfalls to evaluate effects of rainfall intensity (45, 60, 75, 90, 105 and 120 mm/h) and slope gradient (5°, 10°, 15°, 20° and 25°) on dissolved and adsorbed nitrogen loss. Here, we show that there was an overall increasing trend of runoff yield with increased rainfall intensity and also an overall increasing trend of sediment yield with increased slope gradient. TN loss at different slopes was more concentrated under rainfall intensities of 45 mm/h and 60 mm/h and more dispersed under rainfall intensities of 75–120 mm/h. t -Test results showed that there were no significant differences for 6 TN samples at each slope ( p  > 0.05) and 5 TN samples at each rainfall intensity ( p  > 0.05). All NO 3 − -N concentration had a slight declining trend at the beginning of runoff yield and then gradually tended to be gentle with the prolongation of rainfall duration. All NH 4 + -N concentration first showed a sharp decreasing trend and then relatively levelled off with the prolongation of rainfall duration, but it was different and unstable for different rainfall intensities, especially in the first 10 min. Adsorbed TN under bare loess soil occupied 7.0–82.0% of TN loss with an average of 58.6%, while dissolved TN accounted for 18.0–93.0% with an average of 41.4%. NO 3 − -N and NH 4 + -N concentrations respectively accounted for 11.8–73.2% and 1.5–13.3% of TN loss under all combinations of rainfall intensity and slope. There were significant differences in variation trends among NO 3 − -N, NH 4 + -N and TN loss load under various rainfall intensities and slopes, but they all presented an overall upward trend with increased rainfall intensity. Our results provide the underlying insights needed to guide nitrogen loss control in sloping land of the loess hilly region. [ABSTRACT FROM AUTHOR]

Bi metal deposited on Bi2MoO6 composite photocatalysts have been successfully synthesized via a simple reduction method at room temperature with using NaBH4 as the reducing agent. The photocatalytic activity of the composite was evaluated by degradation of rhodamine B (RhB) and bisphenol A (BPA) solution under visible light. The rate constant of Bi/Bi2MoO6 composite to RhB is 10.8 times that of Bi2MoO6, and the degradation rate constant of BPA is 6.9 times of that of Bi2MoO6. Nitrogen absorption–desorption isotherm proved that the increase of specific surface area is one of the reasons for the improvement of photocatalytic degradation activity of Bi/Bi2MoO6 composites. The higher charge transfer efficiency of Bi/Bi2MoO6 is found through the characterization of the photocurrent and impedance, which are attributed to the surface plasmon resonance (SPR) effect produced by the introduction of the metal Bi monomer in the composite. Free radical capture experiments proved that cavitation is the main active species. Based on the above conclusions, a possible mechanism of photocatalytic degradation is proposed. Bi metal has been successfully deposited on Bi2MoO6 by employing a simple reduction method at room temperature, using NaBH4 as reducing agent. The Bi/Bi2MoO6 composites exhibit excellent photocatalytic activity for degradation of RhB and BPA because of the surface plasmon resonance (SPR) effect and the electron transfer ability of Bi. [ABSTRACT FROM AUTHOR]

In this work, the three-dimensional nitrogen-doped nanostructured carbons with hierarchical architectures (3D-NNCsHAs) with high density of defective sites, high surface area and pluralities of pore size distributions was prepared through the pyrolysis of sea-tangle ( Laminaria japonica ), an inexpensive, eco-friendly and abundant precursor. Benefitting from their structural uniqueness, a selective and sensitive ascorbic acid (AA) sensor based on 3D-NNCsHAs was developed. Compared to the glassy carbon electrode (GCE) and the carbon nanotubes modified GCE (CNTs/GCE), the 3D-NNCsHAs modified GCE (3D-NNCsHAs/GCE) presents higher performance towards the electrocatalysis and detection of AA, such as lower detection limit (1 μM), wider linear range (10–4410 μM) and lower electrooxidation peak potential (−0.02 V vs. Ag/AgCl). In addition, 3D-NNCsHAs/GCE also exhibits high anti-interference and anti-fouling abilities for AA detection. Particularly, the fabricated 3D-NNCsHAs/GCE is able to determine AA in real samples and the results acquired are satisfactory. Therefore, the 3D-NNCsHAs can be considered as a kind of novel electrode nanomaterial for the fabrication of selective and sensitive AA sensor for the extensive practical applications ranging from food analysis, to pharmaceutical industry and clinical test. [ABSTRACT FROM AUTHOR]