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1.
采用批量法对温州景山森林公园5种不同城市土壤对Pb和Zn的吸附热力学行为进行了研究。结果表明,吸附等温线符合Freundlich等温式和Temkin等温式,相关系数都在0.85以上,5种土壤对Ph的吸附强度由高到低的次序为C,E,B,A,D,对Zn的吸附强度由高到低的次序为C,E,D,B,A。 相似文献
2.
重量法测定环戊烷在silicalite-1分子筛上的吸附特性 总被引:4,自引:0,他引:4
用智能重量分析技术 (IGA)研究了环戊烷在silicalite 1分子筛上的吸附特性。结果表明 ,随着温度的降低 ,环戊烷的吸附等温线从第一类型过渡为第四类型 ,在 2 5 4K和 2 74K温度下吸附等温线呈现滞后环 ,为第四类型 ,而吸附等温线在 30 4K、32 3K下为阶梯形 ,在 35 4K、42 3K温度下呈第一类型 ,其中 42 3K温度下的吸附等温线可准确的用Langmuir方程来描述。本文同时讨论了吸附质分子间以及吸附质和吸附剂间的相互作用、分子结构特性、分子筛对吸附质分子的空间位阻、分子筛的能量不均匀表面等对环戊烷在silicalite 1分子筛上吸附性能的影响 相似文献
3.
用智能重量分析技术(IGA)研究了环戊烷在silicalite-l分子筛上的吸附特性。结果表明,随着温度的降低,环戊烷的吸附等温线从第一类型过渡为第国类型,在254K和274K温度下吸附等温线呈现滞后环,为第四类型,而吸附等温线在304K、323K下为阶梯形,在354K、423K温度下呈第一类型,其中423K温度下的吸附等温线可准确的用Langmuir方程来描述。本文同时讨论了吸附质分子间以及吸附质和吸附剂间的相互作用、分子结构特性、分子筛对吸附质分子的空间位阻、分子筛的能量不均匀表面等对环戊烷在silicalite-l分子筛上吸附性能的影响。 相似文献
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活性炭纤维的微孔结构水吸附 总被引:3,自引:0,他引:3
测定了两种活性炭纤维(ACF)的氮气、水吸附等温线和XPS,研究了ACF的微孔结构和表面性质,用αs图分析氮吸附等温线获得了ACF的比表面积、微孔容量和微孔径。XPS表明在ACF表面存在多种不同结合状态的氧。水在ACF上的吸附等温线呈V型,具有很大的脱附滞后环。水通过与ACF表面的氧形成氢键发生吸附。ACF表面的初始吸附点多,则在低、中压时的水吸附量就大。 相似文献
8.
新型吸附树脂对苯乙酸的吸附热力学研究 总被引:2,自引:0,他引:2
研究了苯乙酸在新型超高交联树脂AH、NDa-150和大孔吸附树脂(Amberlite XAD-4)上的平衡吸附数据,测定了288K、303K和318K温度下的吸附等温线,结果表明吸附过程符合Langmuir吸附等温方程。苯乙酸在AH、NDa-150上的吸附容量分别比在Amberlite XAD-4上的吸附容量最高高出90%、113%,这主要归因于AH、NDa-150表面的极性基团及树脂的微孔结构.Langmuir吸附等温线、相对吸附容量以及等量吸附焓变表明,苯乙酸在AH树脂上的吸附是物理吸附和化学吸附共同作用的结果.对苯乙酸被3种树脂吸附的吸附焓变、自由能变、吸附熵变也作了计算,并对吸附行为作了合理的解释。 相似文献
9.
疏水界面上标准蛋白质吸附等温线的研究 总被引:3,自引:0,他引:3
测定了几种具有代表性的标准蛋白质在疏水色谱填料上的吸附等温线,除溶菌酶和牛血清白蛋白的吸附近似呈线性外,细胞色素-c,肌红蛋白,胰岛素,a-淀粉酶和卵清蛋白均呈凸型吸附,用Langmuir,计量置换吸附模型(SDM-A)、BET和Jovanovic吸附模型对这些蛋白的吸附等温线拟合后发现,SDM-A关系能够良好描述这7种蛋白吸附,Langmuir关系仅能较好地描述后5种蛋白质的吸附,而Jovano 相似文献
10.
硅胶自非极性溶剂中吸附苯甲酸 总被引:3,自引:0,他引:3
⑴测定了0℃、15℃和20℃时硅胶自四氯化碳中吸附苯甲酸的等温线,等温线为S型的,接近饱和溶液浓度时吸附量急剧上升。用BET二常数公式和D-R方程的类似形式处理了实验结果,最大吸附体积与夺胶比孔容一致。⑵测定了硅胶自四氯化碳-环己烷二元混合溶剂稀溶液中吸附苯甲酸的等温线(20℃)和各溶剂组成时苯甲酸饱和溶液浓度,等温线是Langmuir型的,吸附量与饱和溶液浓度间有直线关系,文中对所得结果给出了合 相似文献
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H. Bahaj M. Bakass C. Bayane J. P. Bellat M. Benchanaa G. Bertrand 《Journal of Thermal Analysis and Calorimetry》2011,103(1):117-123
The adsorbed amounts of water vapor onto polyacrylic polymer (polymer ×10) were measured using a thermogravimetry method as
a function of pressure at 298 and 313 K. The adsorption isotherms are categorized to type II isotherms by IUPAC classification
leading to a hysteresis loop between adsorption and desorption branches. The current study was completed by the measurement
of the adsorption heats at 298 K using a differential scanning calorimetry. The calorimetric curves showed two adsorption
heats domains. These domains have been attributed to the adsorption of “equivalent monolayer” and the condensation of water
between polymeric chains. The correlation of experimental data to some chosen theoretical models shows that the GAB model
is the most adequate to describe water vapor sorption isotherms. 相似文献
12.
P. Staszczuk D. Sternik G. W. Chądzyński E. Robens M. Błachnio 《Journal of Thermal Analysis and Calorimetry》2006,86(1):133-136
Nitrogen
adsorption measured at 77 K was used to characterize the surface heterogeneity
of high-temperature superconductor surfaces. Properties relating to adsorption
and porosity of the solids (adsorption capacity, specific surface area, radii
and volume of the pores, pore-size distribution function) were determined
from nitrogen adsorption–desorption isotherms and atomic force microscopy
(AFM) for a series of oxide superconductors. It is shown that the adsorption
isotherms of all samples are S-shaped and belong to type II according to the
IUPAC classification. On the basis of the nitrogen adsorption isotherms and
AFM data, fractal dimensions were determined and correlations found with adsorption
and porosity parameters. 相似文献
13.
Kondo A Daimaru T Noguchi H Ohba T Kaneko K Kanoh H 《Journal of colloid and interface science》2007,314(2):422-426
We showed water adsorption isotherms at 303 K on water-resistant three-dimensional (3-D) pillared-layer metal organic frameworks (MOFs) with 1-D semi-rectangular pores, of which size depends on the length of ligand. The shapes of all three adsorption isotherms are type I by IUPAC classification showing strong water-MOFs interaction. The adsorbed amount of water molecules on the hydrophilic site of carboxylic group in 2-D sheets coincided with the crystal water amount. The adsorption on the hydrophilic sites occurs at similar relative pressure even if the used ligand is different. 相似文献
14.
Valenzuela-Calahorro C Cuerda-Correa E Navarrete-Guijosa A Gonzalez Pradas E 《Journal of colloid and interface science》2002,248(1):33-40
The knowledge of the adsorption processes of nonelectrolytes from liquid solution on solid materials involves the study of their kinetic and equilibrium aspects as well as the understanding of their thermodynamic functions. However, in most published papers adsorption isotherms are analyzed by using the Giles classification and other proposed equations which are either empirical or based on kinetic or thermodynamic criteria. Our opinion is that both the kinetic and the equilibrium studies must be complementary and that, in general, equations describing the adsorption isotherms come from the kinetic laws governing the different partial processes which determine the global process. These kinetic laws may be derived from single models. In this paper a single model is proposed, which makes it possible to establish a kinetic law satisfactorily fitting a great number of C (concentration) vs t (time) isotherms. This model has been applied to study the adsorption process of prednisolone by six carbonaceous materials from ethanol solution, the specific adsorption rate, and the activation thermodynamic functions being calculated. The results obtained have also been used to analyze the influence of the intraparticle diffusion on the kinetics of the process. 相似文献
15.
U. Messow P. Braeuer A. Schmidt C. Bilke-Krause K. Quitzsch U. Zilles 《Adsorption》1998,4(3-4):257-267
The adsorption excess isotherms of binary mixtures adsorbed on hard solids were calculated by means of surface tension and contact angle measurements using the Gibbs adsorption isotherm equation. The calculation procedure is described in detail using the authors' own measurements of mixtures containing ethylene glycol(1)/water(2) on Teflon and poly(vinyl chloride), and water(1)/n-propanol(2) on Teflon. On the basis of these results and also from surface tensions and contact angles on hard solids published by other authors, all types of isotherms were found as given for porous adsorbents in the classification of Schay and Nagy. In addition to those, new isotherm types are proposed. 相似文献
16.
G. W. Ch?dzyński P. Staszczuk D. Sternik M. B?achnio 《Journal of Thermal Analysis and Calorimetry》2012,108(3):985-989
The porous structure of MgB2 has been investigated using atomic force microscopy (AFM) and sorption techniques. The fractal dimension and surface roughness parameters were evaluated from (AFM) and nitrogen adsorption?Cdesorption isotherms measured at ?196?°C for MgB2 sample. Adsorption capacity, specific surface area, and fractal dimensions were determined from adsorption?Cdesorption isotherms. The sorption isotherms of MgB2 samples were S-shaped and belong to type II according to the IUPAC classification. The results of fractal dimensions of MgB2 surface determined on the basis sorptometry and AFM data are compared. 相似文献
17.
Hafez Maghsoudi Mohammad Soltanieh Hamidreza Bozorgzadeh Ali Mohamadalizadeh 《Adsorption》2013,19(5):1045-1053
Adsorption isotherms of H2S, CO2, and CH4 on the Si-CHA zeolite were measured over pressure range of 0–190 kPa and temperatures of 298, 323, and 348 K. Acid gases adsorption isotherms on this type of zeolite are reported for the first time. The isotherms follow a typical Type-I shape according to the Brunauer classification. Both Langmuir and Toth isotherms describe well the adsorption isotherms of methane and acid gases over the experimental conditions tested. At room temperature and pressure of 100 kPa, the amount of CO2 adsorption for Si-CHA zeolite is 29 % greater than that reported elsewhere (van den Bergh et al. J Mem Sci 316:35–45 (2008); Surf Sci Catal 170:1021–1027 (2007)) for the pure silica DD3R zeolite while the amounts of CH4 adsorption are reasonably the same. Si-CHA zeolite showed high ideal selectivities for acid gases over methane at 100 kPa (6.15 for H2S and 4.06 for CO2 at 298 K). Furthermore, H2S adsorption mechanism was found to be physical, and hence, Si-CHA can be utilized in pressure swing adsorption processes. Due to higher amount of carbon dioxide adsorbed and lower heats of adsorption as well as three dimensional channels of Si-CHA pore structure, this zeolite can remove acid gases from methane in a kinetic based process such as zeolite membrane. 相似文献
18.
表面活性剂在低能固体表面上的吸附 Ⅲ: 聚苯乙烯胶乳粒子对阴离子表面活性剂的吸附 总被引:1,自引:0,他引:1
在无乳化剂的条件下合成了粒径均匀的聚苯乙烯胶乳, 发展了应用表面张力计测定吸附等温线的连续平衡法, 得到不同盐浓度下聚苯乙烯胶乳对十二烷基硫酸钠和十二烷基苯磺酸钠的吸附等温线, 它们属于Giles分类的L2 型或L1 型, 采有两阶段吸附模式讨论了吸附机理, 吸附层结构及等温线类型变化的规律。 相似文献
19.
We discuss the thermodynamics of physical adsorption of gases in porous solids. The measurement of the amount of gas adsorbed in a solid requires specialized volumetric and gravimetric techniques based upon the concept of the surface excess. Excess adsorption isotherms provide thermodynamic information about the gas-solid system but are difficult to interpret at high pressure because of peculiarities such as intersecting isotherms. Quantities such as pore density and heats of adsorption are undefined for excess isotherms at high pressure. These difficulties vanish when excess isotherms are converted to absolute adsorption. Using the proper definitions, the special features of adsorption can be incorporated into a rigorous framework of solution thermodynamics. Practical applications including mixed-gas equilibria, equations for adsorption isotherms, and methods for calculating thermodynamic properties are covered. The primary limitations of the absolute adsorption formalism arise from the need to estimate pore volumes and in the application to systems with larger mesopores or macropores at high bulk pressures and temperatures where the thermodynamic properties may be dominated by contributions from the bulk fluid. Under these circumstances a rigorous treatment of the thermodynamics requires consideration of the adsorption cell and its contents (bulk gas, porous solid and confined fluid). 相似文献
20.
G. W. Chądzyński P. Staszczuk D. Sternik M. Błachnio 《Journal of Thermal Analysis and Calorimetry》2008,94(3):623-626
Properties relating to porosity of solids (fractal dimensions, surface roughness parameters) were evaluated from atomic force
microscopy (AFM) and nitrogen adsorption-desorption isotherms measured at 77 K for selected high-temperature [(RE) Ba2Cu3O7−x, RE=Y, Sm] superconductors. Adsorption capacity, specific surface area, fractal dimensions were determined from adsorption-desorption
isotherms. The adsorption isotherms of all samples were S-shaped and belong to type II according to the IUPAC classification.
A linear relationship was demonstrated between the fractal coefficients calculated by using the two methods and values of
adsorption capacity of monolayer. 相似文献