Application of gas chromatography for the study of precipitated calcium carbonate

Ahsan, Tanweer; Colenutt, B.A.; Sing, K. S. W.

doi:10.1016/s0021-9673(00)94261-4

Cited by 19 publications

(7 citation statements)

References 9 publications

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“…Although there are quite a number of papers on sorption of organic vapors to soils, there is only a limited set of literature data that can be used for a validation of eqs 2 and 7. Data produced at so-called 0% RH are of little use because (i) they are not relevant under environmental conditions; (ii) they are not reproducible because small changes in the traces of water that are always present in any gas phase have a huge impact on the adsorption of organic compounds (8,52); and (iii) the strong, uncontrollable and highly nonlinear influence of humidity close to 0% RH (25) makes it impossible to use such data for an interpolation or extrapolation of adsorption data to higher humidities.…”

Section: Resultsmentioning

confidence: 99%

Adsorption of Organic Vapors to Air-Dry Soils: Model Predictions and Experimental Validation

Goss

Buschmann

Schwarzenbach

2004

Environ. Sci. Technol.

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Soil/air equilibrium partitioning has an important impact on the environmental distribution and fate of many organic chemicals. Modeling approaches that cover this process commonly assume that sorption in soil only occurs in soil organic matter. However, many researchers have already shown thatthis is not even correctfor nonpolar compounds in air-dry soils. Here, we extend the existing data set on sorption in air-dry soils by using a large and very diverse set of organic compounds covering many different functional groups for two standard soils and for relative humidity between 50 and 90%. The experimental data presented here as well as those from the literature are then used to examine two different modeling approaches: one that only considers absorption in soil organic matter and one that also considers adsorption to mineral surfaces. The results clearly show that sorption in air-dry soil cannot be explained when adsorption to mineral surfaces is ignored. Only the model that considers both sorbing phases, organic matter and mineral surfaces, gives good agreement for all experimental data. Our model for predicting adsorption to mineral surfaces does not require any further fitting with experimental data; thus, it can readily be incorporated into existing fate models in order to improve the description of the soil/air partition process.

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Section: Resultsmentioning

confidence: 99%

Adsorption of Organic Vapors to Air-Dry Soils: Model Predictions and Experimental Validation

Goss

Buschmann

Schwarzenbach

2004

Environ. Sci. Technol.

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“…Thus, it is not related to any particular alkane molecule and, because of its incremental character, is no longer dependent on the choice of the reference state. 20 Alkanes have also been used in conjunction with unsaturated and aromatic hydrocarbons to study specific interactions of different surfaces [20][21][22][23][24][25][26][27] in terms of enthalpy and free energy of adsorption. The comparison of ∆G°values of n-alkenes and n-alkanes was used to study the effect of the π bond interactions with electron acceptor sites on the surface.…”

Section: Methodsmentioning

confidence: 99%

“…Alkanes have also been used in conjunction with unsaturated and aromatic hydrocarbons to study specific interactions of different surfaces − in terms of enthalpy and free energy of adsorption. The comparison of Δ G ° values of n -alkenes and n -alkanes was used to study the effect of the π bond interactions with electron acceptor sites on the surface. − ,, The specific interaction parameter ε π was defined by the following equation: Based on the well-known electronic structure of alkanes and alkenes, this parameter can be taken as a measure of the specific (electron acceptor) interaction capacity of the surface. , An increase in the value of ε π is related to an increase in the average number and strength of acidic sites which are able to interact stronger with π bonds of alkenes.…”

Section: Methodsmentioning

confidence: 99%

Comparison of the Surface Features of Two Wood-Based Activated Carbons

Salame

Bandosz

2000

Ind. Eng. Chem. Res.

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The surface features of two carbons of wood origin were compared. One sample was manufactured using phosphoric acid activation and the other using potassium hydroxide activation. To check the susceptibility to oxidation and the stability of the porous structure, the samples were oxidized with ammonium persulfate. Structural properties of carbons and their oxidized counterparts were determined using sorption of nitrogen. Surface acidity was evaluated using Boehm titration, potentiometric titration, inverse gas chromatography, and diffuse reflectance FTIR. It was demonstrated that, despite the same wood origin, the carbons significantly differ in their pore structure and surface chemistry. The carbon obtained using KOH activation is homogeneously microporous with high surface area around 2300 m2/g (BET). On the other hand, the carbon manufactured using phosphoric acid contains a high volume of mesopores and its surface area is significantly lower. The carbons also differ in their surface chemistry and susceptibility to oxidation.

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“…Schmitt et al 6 found that the adsorption behaviour of n ‐alkanes was similar for stearic acid and non‐treated calcium carbonates, although the entropic contributions to the interactions were different. Ahsan and co‐workers7, 8 also measured the surface energetics of calcium carbonates, and showed that the enthalpy of adsorption of alkane probes was reduced after treatment with stearic acid. Ahsan and Taylor8 measured the impact strength of PP–CaCO 3 composites where the filler had been treated with varying levels of stearic acid and found a correlation with the surface free energy measured by IGC.…”

Section: Introductionmentioning

confidence: 99%

Surface modification of calcium carbonates studied by inverse gas chromatography and the effect on mechanical properties of filled polypropylene

Price

Ansari

2004

Polymer International

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Inverse gas chromatography (IGC) has been used to characterize the surfaces of a pure calcitic calcium carbonate as well as samples that had been treated with sodium polyacrylate and/or stearic acid. The dispersive components of the surface free energy for the pure material agreed well with related literature data. Polar contributions to the surface interactions with a range of probes were determined. The results show that the surface treatments reduced the polarities of the surfaces and that modification with stearic acid produced a non-polar, low-energy surface. Some mechanical properties of the polypropylene composites containing the modified calcium carbonates were found to correlate well with the filler surface energies.

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Application of gas chromatography for the study of precipitated calcium carbonate

Cited by 19 publications

References 9 publications

Adsorption of Organic Vapors to Air-Dry Soils: Model Predictions and Experimental Validation

Adsorption of Organic Vapors to Air-Dry Soils: Model Predictions and Experimental Validation

Comparison of the Surface Features of Two Wood-Based Activated Carbons

Surface modification of calcium carbonates studied by inverse gas chromatography and the effect on mechanical properties of filled polypropylene

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