A Simplified Ethylene Glycol Monoethyl Ether Procedure for Assessment of Soil Surface Area

Cihacek, Larry; Bremner, J. M.

doi:10.2136/sssaj1979.03615995004300040045x

Cited by 173 publications

(76 citation statements)

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“…The properties of the porous media are summarized in Table 1. Specific surface areas were measured using the ethylene glycol monoethyl ether (EGME) procedure [Chihacek and Bremmer, 1979] Table 2. Partition coefficients of the VOCs for the three porous media were assumed to be linear for the concentrations tested.…”

Section: Introductionmentioning

confidence: 99%

Air sparging: Air‐water mass transfer coefficients

Braida¹,

Ong²

1998

Water Resources Research

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Abstract. Experiments investigating the mass transfer of several dissolved volatile organic compounds (VOCs) across the air-water interface were conducted using a single-airchannel air-sparging system. Three different porous media were used in the study. Air velocities ranged from 0.2 cm s-• to 2.5 cm s-•. The tortuosity factor for each porous medium and the air-water mass transfer coefficients were estimated by fitting experimental data to a one-dimensional diffusion model. The estimated mass transfer coefficients K G ranged from 1.79 x 10 -3 cm min -• to 3.85 x 10 -2 cm min -•. The estimated lumped gas phase mass transfer coefficients KGa were found to be directly related to the air diffusivity of the VOC, air velocity, and particle size, and inversely related to the Henry's law constant of the VOCs. Of the four parameters investigated, the parameter that controlled or had a dominant effect on the lumped gas phase mass transfer coefficient was the air diffusivity of the VOC. Two empirical models were developed by correlating the Damkohler and the modified air phase Sherwood numbers with the air phase Peclet number, Henry's law constant, and the reduced mean particle size of porous media. The correlation developed in this study may be used to obtain better predictions of mass transfer fluxes for field conditions. IntroductionIn situ air sparging has been used for more than 10 years with varying success for the remediation of aquifers contaminated with dissolved volatile organic compounds (VOCs) and nonaqueous phase liquids (NAPLs). In a typical air-sparging system, clean air is injected below the water table to Even though the VOC concentrations at the air-water interface may more accurately represent the physics of the system, measurement of the VOC concentrations at the air-water interface is not possible. Therefore the standing issue in the estimation of the mass transfer coefficients between gas and liquid phases during air sparging is to define in a practical way, the driving force (i.e., concentration gradient) for the volatilization of VOCs. Since an air-sparged porous medium is not a completely mixed system, the task of defining the concentration gradient is more challenging. The objective of this work was to investigate the air-water mass transfer process for dissolved VOCs using an experimental setup where the interfacial area between the air and liquid phases was held constant. Mass transfer coefficients deter- Materials and MethodsThe approach taken was to use an experimental setup which would simulate air flow in a single discrete air channel in saturated porous media. Table 2. Partition coefficients of the VOCs for the three porous media were assumed to be linear for the concentrations tested. The VOC partition coefficients were determined individually using the head space technique as described by Ong and Lion [1991]. Linear partition coefficients were found to range between 0.018 mL g-• and 0.082 mL g-• and

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Section: Introductionmentioning

confidence: 99%

Air sparging: Air‐water mass transfer coefficients

Braida¹,

Ong²

1998

Water Resources Research

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“…They followed the principles of the ethylene glycol method originally proposed by Dyal and Hendricks (1950) and subsequently modified by a number of workers including Martin (1955), Bower and Goertzen (1959), and Sor and Kemper (1959). The EGME method has the advantage that the sorption equilibrium is reached more rapidly than in the ethylene glycol method Heilman et aL, 1965;Cihacek and Bremner, 1979).…”

Section: Introductionmentioning

confidence: 99%

Fourier-Transform Infrared Study of Ethylene Glycol Monoethyl Ether Adsorbed on Montmorillonite: Implications for Surface Area Measurements of Clays

Nguyen

1987

Clays and clay miner.

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Abstract-Infrared spectra of 2-ethoxyethanol (ethylene glycol monoethyl ether, EGME) adsorbed on Camontmorillonite were obtained using diffuse-reflectance infrared-Fourier-transform (DRIFT) and attenuated total-reflectance (ATR) spectroscopy. The molecular conformation of adsorbed EGME shows predominantly a gauche configuration for the CH2-CH2 linkage as originally present in the liquid. The orientation of the adsorbed EGME molecule in the interlamellar region of the clay was deduced from measurements of the polarized ATR spectra. The planar zig-zag skeleton of the molecule appears to have its long axis tilted at an angle of 44 ~ to the clay surface; the molecule is in van der Waals contact with both adjacent surfaces. Further, the plane of the skeleton of the molecule is tilted at an angle of 69 ~ to the clay surface. This orientation leads to estimates of the d-value of the clay-EGME complex and of the surface area occupied by each molecule. These values are in excellent agreement with independent measurements of both parameters. The full surface coverage on montmorillonite is represented by a single layer of tilted EGME molecules shared by two adjacent clay sheets; each molecule occupies a total surface area consisting of one portion (25.4 A2) on the lower surface of the interlayer plus another portion (14.8 ,~z) on the upper surface. The implication of this model for materials such as kaolinite, where adsorption takes place on the external surface only, is that on these materials each EGME molecule occupies 20/~2 at full surface coverage.

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“…When smectite is present, changes in its abundance thus control total MSA determination because of this great disparity in surface area. The EGME method also provides an approximation of a single molecular monolayer coating of ethylene glycol on mineral surfaces when in equilibrium with an EGME vapor (39). We use this molecular monolayer coating to compare with the OM:MSA in our natural samples deposited under varying redox conditions (Fig.…”

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Clay mineral continental amplifier for marine carbon sequestration in a greenhouse ocean

Kennedy

Wagner

2011

Proc. Natl. Acad. Sci. U.S.A.

119

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The majority of carbon sequestration at the Earth’s surface occurs in marine continental margin settings within fine-grained sediments whose mineral properties are a function of continental climatic conditions. We report very high mineral surface area (MSA) values of 300 and 570 m 2 g in Late Cretaceous black shales from Ocean Drilling Program site 959 of the Deep Ivorian Basin that vary on subcentennial time scales corresponding with abrupt increases from approximately 3 to approximately 18% total organic carbon (TOC). The observed MSA changes with TOC across multiple scales of variability and on a sample-by-sample basis (centimeter scale), provides a rigorous test of a hypothesized influence on organic carbon burial by detrital clay mineral controlled MSA. Changes in TOC also correspond with geochemical and sedimentological evidence for water column anoxia. Bioturbated intervals show a lower organic carbon loading on mineral surface area of 0.1 mg-OC m -2 when compared to 0.4 mg-OC m -2 for laminated and sulfidic sediments. Although either anoxia or mineral surface protection may be capable of producing TOC of < 5%, when brought together they produced the very high TOC (10–18%) apparent in these sediments. This nonlinear response in carbon burial resulted from minor precession-driven changes of continental climate influencing clay mineral properties and runoff from the African continent. This study identifies a previously unrecognized land–sea connection among continental weathering, clay mineral production, and anoxia and a nonlinear effect on marine carbon sequestration during the Coniacian-Santonian Oceanic Anoxic Event 3 in the tropical eastern Atlantic.

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A Simplified Ethylene Glycol Monoethyl Ether Procedure for Assessment of Soil Surface Area

Cited by 173 publications

References 0 publications

Air sparging: Air‐water mass transfer coefficients

Air sparging: Air‐water mass transfer coefficients

Fourier-Transform Infrared Study of Ethylene Glycol Monoethyl Ether Adsorbed on Montmorillonite: Implications for Surface Area Measurements of Clays

Clay mineral continental amplifier for marine carbon sequestration in a greenhouse ocean

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