High-Pressure Sorption of Methane, Ethane, and Their Mixtures on Shales from Sichuan Basin, China
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High-pressure sorption isotherms of CH4, C2H6, and their mixtures on shales from Sichuan Basin, China, were measured by a volumetric method. The sorption measurements for pure components were conducted at 40, 60, and 80 °C, with the pressure up to ∼20 MPa. The binary sorption measurements were performed to ∼11 MPa at 40 °C and ∼16 MPa at 80 °C, and two feed gas compositions of C2H6 (10 and 20%) were studied. The excess sorption isotherms of pure components were fitted by the three-parameter Langmuir model, and the extended Langmuir (EL) model was used to predict the absolute sorption isotherms of binary mixtures. The sorption discrepancies of CH4/C2H6 were discussed, and the preferential sorption of C2H6 was quantitatively analyzed. As the temperature decreases, the excess sorption isotherm of C2H6 presents a more sharp increase and then a more rapid decrease. The excess sorption isotherms of C2H6 at 40 °C show significant differences with other CH4/C2H6 isotherms. In comparison to gas composition, the temperature has a more notable effect on binary excess sorption isotherms. C2H6 shows a stronger affinity than CH4, and its stronger affinity is less significant in the mixtures compared to the single component. The sorption selectivity presents a first increasing and later decreasing trend with the pressure. The presence of C2H6 mainly reduces the excess sorption of CH4 at a high pressure, and its effect at a low pressure is negligible.Coalbed Methane
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The sorption kinetic and isothermal behaviors of BDE-47 on three natural soils with different soil organic matter fractions(fOC) were studied. The results demonstrated that a two(fast and slow)-compartment first-order model was more appropriate for describing the sorption kinetic data, compared to a one-compartment first-order model, especially in the initial sorption stage within 49 h. The fast sorption was dominant during the whole sorption process from beginning to the apparent sorption equilibrium; while the contribution of the slow sorption to the total sorption amount gradually increased over time and then attained to a plateau at 97 h. The achieving time to the individual sorption capacity for the fast sorption was much shorter than that for the slow sorption. The contribution of the fast sorption to the increase in the total sorption amount of BDE-47 was prevailing at the start of sorption process from 3 h to 5 h; while the fraction of the slow sorption became principal in the subsequent stage of sorption process. Within the narrow equilibrium concentration range due to the fairly low aqueous solubility of BDE-47, the fitting results by the linear partitioning model were comparable with the linear portion by the nonlinear Freundlich model in this study. As for the Freundlich model, the nonlinear exponent(n) values of BDE-47 for the two samples with lower fOC(0.72%) or higher fOC(7.90%) were obviously lower than 1.0(0.75±0.03 and 0.74±0.02, respectively), suggesting somewhat nonlinear sorption characteristics in the studied range of apparent equilibrium concentrations of BDE-47; whereas the linear behavior of BDE-47 for the left sample with medium fOC(2.86%) was indicated by its n value much closed to 1.0(1.03±0.03).
Isothermal process
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In this paper,the container wall sorption percentage and the sorption ratio of Am betweensolution and such sorption materials as bentonite are studied with the HPGe detector connected-with S-85 multichannel system,the influence of container wall sorption on sorption ratio also isdiscussed.The results show that the container wall sorption with solid sorptive materials is lowerthan that without solid sorptive materials. The container wall sorption should be considered forthe sorptive materials with low sorption ratio values and can be neglected for those with highsorption ratio values.
Bentonite
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Sorption isotherms of eleven purified anthraquinone disperse dyes on Nylon 6 film from water were measured at 60 and 80°C. Analysis of the isotherms indicates that two concurrent modes of sorption are operative in the dye sorption; Nernst type partitioning and a Langmuir sorption. Normally, the amount of dye sorbed by the Langmuir sorption (CL) was much smaller than that (CP) by the partitioning. However, the ratio CL/(CP+CL) at saturated dye concentration in water, which is a measure to indicate the contribution of Langmuir sorption to the total dye sorption, increased with an increase in the number of functional group capable of forming intermolecular hydrogen bond in dye. These findings suggest that the hydrogen bonding between the dyes and Nylon 6 plays an important role in the Langmuir sorption.
Anthraquinones
Langmuir adsorption model
Disperse dye
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Sorption isotherms of purified azo disperse dyes and their model compounds on nylon 6 from water are measured in a temperature range of 40-90°C. Most isotherms are curved, convex upward, in the range of low dye concentration in water. Analysis of the isotherms using Freundlich sorption and a dual-mode sorption model shows that the isotherms follow the latter, in which Nemst-type partitioning and simple Langmuir sorption are concurrently operative. The amount of dye ( C L ) on the polymer sorbed by Langmuir sorption is usually much smaller than that ( Cp) by partitioning. Dyes with the hydrogen atom capable of forming an intermolecular hydrogen bond show high substantivity for nylon 6. The hydrogen bond between nylon 6 and the hydrogen atom of the amino group or the 4- N-substituted-(2-hydroxyethyl) group in the dye seems to be involved in Langmuir sorption. For dyes with 4-amino and two 4- N-substituted-(2-hydroxyethyl) groups, the number of Langmuir sorption sites ( S) decreases gradually with increasing temperature, while for dyes with only one 4- N- substituted-(2-hydroxyethyl ) group, S decreases abruptly with increasing temperature. In some cases, the Langmuir sorption mode seems to diminish at a high temperature: the sorption isotherms become almost linear.
Langmuir adsorption model
Disperse dye
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In research carried out measurements of weight loss with API 5L grade B material in a solution of HCl 1 M. Extract Myrmecodia Pendans is used as a corrosion inhibitor. Immersion time was 2 hours, while the temperature variations used are 30, 40 and 50°C. Extracts of the ants 100-500 mg / L (multiples of 100 mg / L). In this study will also be analyzed with some models of adsorption mechanisms, including the Langmuir, Freundlich, and Temkin. This study aimed to determine the appropriate method of adsorption isotherms on each system. Adsorption equations of the model will be obtained values of free energy of a system. With the known value of free energy, it can be seen whether the adsorption occurs in physics or chemistry. This related to the surface protective layer formed on the surface absorption extract Myrmecodia Pendans. The results showed that the adsorption followed the Langmuir adsorption method at 30 and 40°C, while the temperature of 50°C followed Freundlich adsorption methods.
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Four sorption models(Langmuir,Freundlich,Redlich-Peterson,Nernst) were applied to discuss the mechanism of the sorption of acid dyes on male silk.The influence of dyeing temperature on sorption parame-ters was investigated.The experimental data showed that Langmuir and Redlich-Peterson could well describe the sorption behavior of acid dyes on male silk.The interaction force between acid dyes and male silk was elec-trostatic attraction.The sorption process of Telon blue A2R was typical exothermic,Langmuir sorption constant KL decreased with the increase of dyeing temperature.
Acid dye
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The sorption kinetics and isotherms of BDE-28 on three natural soils with different soil organic matter fractions (f(oc)) were investigated. The results indicated that a two (fast and slow)-compartment first-order model was more appropriate for describing the sorption kinetic data, compared to a one-compartment first-order model, especially in the initial sorption stage within 25 h. The fast sorption was predominant during the whole sorption process from beginning to the apparent sorption equilibrium; while the contribution of the slow sorption to the total sorption amount gradually increased and then achieved a plateau at 49 h or 55 h. The approaching time to the individual sorption capacity for the fast sorption was much shorter than that for the slow sorption. The contribution of the fast sorption to the increase in the total sorption amount of BDE-28 was prevailing at the beginning of sorption process from 2.5 h to 4.5 h; whereas the fraction of the slow sorption became primary at the subsequent stage of sorption process. The fitting results by the Dubinin-Ashtakhov (DA) model were comparable with those by the Freundlich model in the range of apparent equilibrium concentration studied. As for the Freundlich model, the nonlinear exponent (n) values of BDE-28 for the two samples with lower f(oc) (0.72%) or higher f(oc) (7.90%) approached to 1.0 (1.03 +/- 0.05 and 1.00 +/- 0.05, respectively), suggesting the linear sorption characteristics in the studied range of apparent equilibrium concentrations of BDE-28; while the nonlinear behavior of BDE-28 for the left sample with medium f(oc) (4.42%) was indicated by its n value less than 1.0 (0.89 +/- 0.04).
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