Pore characterization of different types of coal from coal and gas outburst disaster sites using low temperature nitrogen adsorption approach

Qi, Lingling; Tang, Xu; Wang, Zhaofeng; Peng, Xinshan

doi:10.1016/j.ijmst.2017.01.005

Cited by 350 publications

(124 citation statements)

References 38 publications

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“…The hysteresis phenomenon can be associated with the capillary condensation in mesoporous structures. Different forms of the hysteresis loop are caused by different types of adsorbent and sorption experimental conditions such as temperature and pressure [37]. According to the IUPAC, the curve shown in Fig.…”

Section: Kinetics and Batch Adsorption Experimentsmentioning

confidence: 99%

Synthesis of a-cellulose/magnetite/polypyrrole composite for the removal of reactive black 5 dye from aqueous solutions

Diaz‐Flores¹,

Guzmán-Álvarez²,

Ovando‐Medina³

et al. 2019

Desalination and Water Treatment

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A composite was obtained from a-cellulose coated with magnetite nanoparticles and conducting polypyrrole (PPy). The magnetite nanoparticles were synthesized by the coprecipitation method from FeCl 2 and FeCl 3 salts. The composite was obtained by pyrrole polymerization in the presence of a mixture of a-cellulose and magnetite nanoparticles. The magnetite nanoparticles and composite were characterized by FTIR and UV/Vis-NIR spectroscopies, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and thermogravimetric analyses (TGA). XRD analysis demonstrated that magnetite nanoparticles with the typical cubic structures of Fe 3 O 4 were obtained. SEM analysis showed that magnetite nanoparticles had irregular morphology with average size of 13 nm, whereas the composite consisted of spherical nanoparticles of PPy coating a-cellulose fibers and magnetite nanoparticles. Batch aqueous adsorption experiments of the reactive black 5 (RB5) dye onto the synthesized material were conducted. The results showed that for the adsorption experiments set to initial pH of 3.0; the maximum adsorption capacity was 62.31 mg of dye g-1 of composite, while a value of 21.67 mg of dye g-1 of composite was obtained when the initial solution pH was set to 7.0. Adsorption isotherms for the RB5 dye were well described by the Langmuir model. The transient adsorption process of the RB5 dye onto the composite was described by a general three-resistance model; allowing the estimation of the effective diffusivity, D 0 , and the adsorption rate coefficient, k 1. For the adsorption experiments with an initial pH value set to 3.0, D 0 was estimated at 4.37 × 10-11 m 2 s-1 while k 1 was 7.30 × 10-7 L mg-1 .s.

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Section: Kinetics and Batch Adsorption Experimentsmentioning

confidence: 99%

Synthesis of a-cellulose/magnetite/polypyrrole composite for the removal of reactive black 5 dye from aqueous solutions

Diaz‐Flores¹,

Guzmán-Álvarez²,

Ovando‐Medina³

et al. 2019

Desalination and Water Treatment

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“…Wang et al [30] found that the gas desorption of coal at a constant temperature of −36°C was lower compared to the gas desorption at a temperature below −36°C, while the room temperature gas desorption was lower than the gas desorption at normal temperatures. e gap between the gas desorption amounts under the three experimental conditions gradually increased with the passage of time, indicating that the inhibiting e ect of low-temperature conditions on coal gas desorption was very signi cant.…”

Section: E Ect Of the Temperature On The Desorption Properties Ofmentioning

confidence: 99%

Orthogonal Experimental Study on Multifactor Conditions for Gas Desorption in Coal

Wang

et al. 2019

Advances in Civil Engineering

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The isothermal adsorption experiment of coal is an important method to study the mechanism of coal gas desorption. The orthogonal experiment is used to compare the gas desorption mechanism of coal under multifactor conditions, such as the particle size, temperature, pressure, moisture content, and molding pressure. The sensitivity of five factors was used to conduct regression analysis. The sensitivity and influence degree of five factors on the coal gas desorption capacity were analyzed. The results showed the following: (1) the effect of the coal sample particle size, temperature, pressure, moisture content, and molding pressure of coal on the sensitivity of desorption capacity is shown as C (pressure) > B (temperature) > A (particle size) > D (moisture content) > E (molding pressure); (2) the regression analysis of various factors for gas adsorption indicates that the degree of correlation of the multivariate quadratic regression equation is higher compared to that of the multivariate one-time regression equation; and (3) the coal sample particle size, temperature, pressure, moisture content, and type of gas desorption can well represent the gas desorption capacity of a coal sample under various conditions. The smaller the particle size of the coal sample, the higher the ambient temperature, the higher the gas pressure, the lower the moisture content of the coal sample, and the greater the gas desorption per unit mass in 30 min after coal sample gas adsorption equilibrium. The orthogonal test results have important theoretical significance for guiding gas adsorption and desorption tests of coal. For coal and gas outburst prediction, the coal seam gas flow mechanism, coal gas content prediction, and calculation of the mining coal gas emission have important practical significance for gas explosion accident prevention.

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“…5 Dynamic properties of interest include the following: density, wave velocity, porosity, strength, scale effect, bedding effect, the influence of moisture, and energy dissipation. 15,[33][34][35][36][37][38][39][40][41][42][43][44][45] Very high loading rate dynamic tests are usually conducted by using split Hopkinson pressure bar (SHPB) systems, 30,46 to determine dynamic properties of brittle materials including concretes, ceramics, rocks, and coals under wide range of impact loadings or strain rates of 10 1 -10 4 /s. [47][48][49][50][51][52][53] For determination of dynamic properties of different coals, the principal attributes are to recovery the dynamic magnitudes of Young's modulus and compressive/tensile strength based on the stress-strain curves at very high strain rates.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation on dynamic strength and energy dissipation characteristics of gas outburst‐prone coal

Fan

Elsworth

et al. 2019

Energy Science & Engineering

113

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We report laboratory experiments to investigate the dynamic failure characteristics of outburst‐prone coal using a split Hopkinson pressure bar (SHPB). For comparison, two groups of experiments are completed on contrasting coals—the first outburst‐prone and the second outburst‐resistant. The dynamic mechanical properties, failure processes, and energy dissipation of both outburst‐prone and outburst‐resistant coals are comparatively analyzed according to the obtained dynamic compressive and tensile stress‐strain curves. Results show that the dynamic stress‐strain response of both outburst‐prone and outburst‐resistant coal specimens comprises stages of compression, linear elastic deformation, then microfracture evolution, followed by unstable fracture propagation culminating in rapid unloading. The mechanical properties of both outburst‐prone and outburst‐resistant coal specimens exhibit similar features: The uniaxial compressive strength and indirect tensile strength increase linearly with the applied strain rate, and the peak strain increases nonlinearly with the strain rate, whereas the elastic modulus does not exhibit any clear strain rate dependency. Differences in the dynamic failure characteristics between outburst‐prone and outburst‐resistant coals also exist. The hardening effect of strain rate on outburst‐prone coal is more apparent than on outburst‐resistant coal, which is reflected in the dynamic increase factor at the same strain rate. However, the dynamic strength of outburst‐prone coals is still lower than that of outburst‐resistant coals due to its low quasi‐static strength. The dissipated energy of outburst‐prone coal is smaller than that of outburst‐resistant coal. Therefore, the outburst‐prone coal, characterized by low strength, high deformability, and small energy dissipation when dynamically loaded to failure, is more favorably disposed to the triggering and propagation of gas outbursts.

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Pore characterization of different types of coal from coal and gas outburst disaster sites using low temperature nitrogen adsorption approach

Cited by 350 publications

References 38 publications

Synthesis of a-cellulose/magnetite/polypyrrole composite for the removal of reactive black 5 dye from aqueous solutions

Synthesis of a-cellulose/magnetite/polypyrrole composite for the removal of reactive black 5 dye from aqueous solutions

Orthogonal Experimental Study on Multifactor Conditions for Gas Desorption in Coal

Experimental investigation on dynamic strength and energy dissipation characteristics of gas outburst‐prone coal

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