Sorption and diffusion of chlorinated methanes in moist clay

Cabbar, H. Canan; Varol, Nesrin; McCoy, Benjamin J.

doi:10.1002/aic.690440613

Cited by 10 publications

(6 citation statements)

References 21 publications

(25 reference statements)

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“…On the other hand, the water vapour on ORFS has no influence on cyclohexane uptake at the measured p/p sat . The decrease of cyclohexane uptake in the presence of water on kaolinite and FS is consistent with the observations previously reported on non‐polar organic solvent on minerals and soils . The values of k ad and k des of cyclohexane increased significantly in the presence of water on kaolinite.…”

Section: Resultssupporting

confidence: 90%

“…The decrease of cyclohexane uptake in the presence of water on kaolinite and FS is consistent with the observations previously reported on non-polar organic solvent on minerals and soils. [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] The values of k ad and k des of cyclohexane increased significantly in the presence of water on kaolinite. In contrast, the water vapour has little effect on the k ad and k des of cyclohexane on FS and ORFS.…”

Section: Mixed Vapours Of Cyclohexane and Watermentioning

confidence: 99%

“…For instance, the difference in sorption properties of solvent vapours on kaolinite and quartz sands is solely due to the differences in their specific surface areas . When water vapour or liquid water is present in the substrate matrix, the adsorption of non‐polar organic solvent vapour on minerals and soils was significantly lower . The organic matter in soil minerals plays an important role in both the amount of solvent vapour uptake and the sorption kinetics, where extremely slow adsorption/desorption of organic vapour was observed .…”

Section: Introductionmentioning

confidence: 99%

“…[24,25] When water vapour or liquid water is present in the substrate matrix, the adsorption of non-polar organic solvent vapour on minerals and soils was significantly lower. [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40] The organic matter in soil minerals plays an important role in both the amount of solvent vapour uptake [41][42][43][44] and the sorption kinetics, where extremely slow adsorption/desorption of organic vapour was observed. [45][46][47] An important difference in oil sands applications is that the organic materials dominated by petroleum components are deficient in oxygen compared to soil organic matter.…”

Section: Introductionmentioning

confidence: 99%

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Sorption equilibrium and kinetics for cyclohexane, toluene, and water on Athabasca oil sands solids

et al. 2016

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The sorption of solvents from the vapour phase to solid substrates is important in producing heavy oil and bitumen, particularly from the oil sands. We investigated the sorption and desorption equilibrium and kinetics of cyclohexane, toluene, and water on kaolinite, fine solids, and organic‐rich fine solids isolated from Athabasca oil sands over a wide range of solvent vapour concentrations using a gravimetric method. The isotherms for both adsorption and desorption of solvent vapour were determined, and the Brunauer‐Emmett‐Teller equation was used to fit the experimental data. The initial kinetic rate constants for the adsorption and desorption of solvent vapour were determined with the linear driving force model. The results were compared and discussed in terms of the type of solvent, the content of organic materials, and the surface area of the solid substrates. The results suggest that, in addition to the adsorption of solvent on mineral surfaces, the contribution from solvent partitioning in the organic materials and the porosity resulting from high amounts of organic materials are significant factors for solvent uptake and kinetic rate constants. In mixed solvent vapours, the competitive sorption of water and cyclohexane was observed in the solid substrates. However, the degree of competitiveness decreased with an increase in the content of organic materials in the substrates.

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Section: Resultssupporting

confidence: 90%

Section: Mixed Vapours Of Cyclohexane and Watermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Sorption equilibrium and kinetics for cyclohexane, toluene, and water on Athabasca oil sands solids

et al. 2016

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“…Moments higher than the second are usually not used, due to increased sensitivity to measurement errors. This method is often used for analyzing results of different implementations of the diffusion cell technique, either in conjunction with time domain analysis or by itself (e.g., Cabbar et al, 1998).…”

Section: Parameter Estimationmentioning

confidence: 99%

An approach for the optimization of transient diffusion cell measurements

Sun¹,

Magalhães

Costa

2001

Can J Chem Eng

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arameter estimation from experimental data subject to interference of secondary phenomena may be troublesome. A correct design of P the apparatus employed may be decisive for the quality of the measurements. A strategy for correctly identifying the optimal sets of design variables is therefore needed in order to minimize such problems. The present work elaborates on the issue of diffusion measurements, using a diffusion cell setup, being affected by film mass transfer resistance, and how a methodical theoretical analysis can be performed in order to clarify the proper design procedures. Despite the fact that some of the conclusions obtained might seem intuitive, the emphasis should be placed on the systematic approach employed, which can be generalized to problems of an altogether different nature.The transient diffusion cell method (also commonly known as transient Wicke-Kallenbach experiment) is one of the most widely used techniques for determining effective diffusivities of gases in porous solids (Haynes, 1988;Karger and Ruthven, 1992;Do, 1998) and new implementations are often introduced (e.g., Talu et al., 1998). Two streams with different initial tracer concentrations flow along the two opposite sides of the sample pellet. The total pressure is the same on both sides. A concentration step change is introduced on the top chamber's inlet and the time-dependent concentration responses at the two chamber outlets are used to estimate the parameters of mass transport across the pellet. A complete review of the technique was given by Park et al. (1 996).This work deals with the particular case of a film mass transfer resistance being present in series with the intra-pellet diffusion. The existence of such resistance complicates the parameter estimation process and loss of precision and sensitivity may occur in the estimation of the effective diffusivity. In the literature, it is often assumed that this resistance is negligible (Dogu and Smith, 1975; Burghardt et al., 1988; Sortichos, 1992), but without establishing the conditions for the verification of such hypothesis. Lu and Rodrigues (1992), on the other hand, developed a criteria based on the first moment of the system's response data, in order to quantitatively define a parametric region for neglecting film resistance, in the case of a diffusion-cell where intrapellet diffusion and convection take place simultaneously and film resistance was present only in the bottom chamber side.This study discusses the development of a general strategy for determining the conditions, in terms of the problem's parameters, where film resistance may be neglected. This particular study is restricted to the case of no 'Author to whom correspondence may be addressed: E-mail address: ccosta@ fe.up.ptIn a diffusion cell experiment, the presence of a film diffusion resistance, in series with intrapellet diffusion, leads to loss of precision in the estimation of intrapellet diffusivities. A general strategy, extendable to other problems, for quantifying a parametric region where f...

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Dynamic Analysis of Diffusion and Adsorption of Water‐Miscible and Water‐Immiscible Organic Vapors in Soil

Kalender

Akosman²

2004

Chem Eng & Technol

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A dynamic analysis of the diffusion and adsorption of water-miscible volatile organic compounds (methanol and acetone) and water-immiscible volatile organic compounds (benzene and toluene) in a soil pellet has been performed experimentally by using the single pellet moment technique. The experiments were conducted in a one-sided single pellet adsorption cell at a temperature of 30 C and varying relative humidities (0, 20, and 40 %). The results obtained with dry and wet systems showed that volatile organic tracers were adsorbed reversibly onto the soil. The overall adsorption equilibrium constants of both water-miscible and water immiscible volatile organic compounds decreased with relative humidity. The sorption of water-immiscible VOCs (benzene) onto soil was found to be much less than that of water-miscible VOCs (methanol). The effective diffusivity of water-immiscible volatile organic vapor (benzene) in the soil did not show a considerable change with relative humidity. In contrast, there was an appreciable change in the effective diffusivity for water-miscible VOCs (methanol) with moisture.

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Sorption and diffusion of chlorinated methanes in moist clay

Cited by 10 publications

References 21 publications

Sorption equilibrium and kinetics for cyclohexane, toluene, and water on Athabasca oil sands solids

Sorption equilibrium and kinetics for cyclohexane, toluene, and water on Athabasca oil sands solids

An approach for the optimization of transient diffusion cell measurements

Dynamic Analysis of Diffusion and Adsorption of Water‐Miscible and Water‐Immiscible Organic Vapors in Soil

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