The Prediction of Asphaltene Adsorption Isotherm Constants on Mineral Surfaces

Mohammadi, Majid; Khamehchi, Ehsan; Sedighi, Mehdi

doi:10.1080/10916466.2011.605091

Cited by 15 publications

(8 citation statements)

References 28 publications

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“…Adsorption of asphaltenes at both organic and inorganic interfaces is a well-known phenomenon reported many times in the literature. − Dynamic adsorption of asphaltenes on quartz and calcite packs and their effect on wettability were documented . Several thermodynamic models were proposed to account for asphaltene adsorption on mineral surfaces. ,,− X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry–time of flight (SIMS–TOF) were used by Gray et al to study the surface after asphaltene adsorption on kaolinite . Maximum thickness of the asphaltene layer was estimated at 11 nm, and no preferential adsorption of nitrogen or sulfur compounds was observed .…”

Section: Introductionmentioning

confidence: 99%

Precipitation of Asphaltenes and Resins at the Toluene–Silica Interface: An Example of Precipitation Promoted by Local Electrical Fields Present at the Silica–Toluene Interface

2014

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Adsorption and desorption of asphaltenes and resins occurring at the silica−toluene interface were used as a tool to investigate phase separation or precipitation promoted by the surface. Adsorption isotherms for this system were obtained as usual, employing commercial silica plates immersed in toluene solutions. After the adsorption of the sample (asphaltenes, asphaltene subfraction A2, resins I, and resins II), the plate was removed, contacted with and retracted from toluene to remove trapped solution, and then immersed again in fresh toluene to measure the desorption. In all cases, the amount desorbed was either insignificant or a small fraction of the amount expected. This could be analyzed in terms of precipitation at the interface promoted by local electrical fields present at the silica−toluene interface; these fields promote molecular polarization, dispersion interactions, and piling up, leading to precipitation. As a result, when the plate with the adsorbed precipitate (material of very low solubility in toluene) is contacted with fresh toluene, desorption is either insignificant or very low. The combine effects of the local electrical fields, molecular polarization, and dispersion interactions are so effective that resin precipitation at the above interface was also obtained. These ideas were found coherent with preliminary atomic force microscopy (AFM) measurements performed on asphaltenes deposited on a glass surface.

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Section: Introductionmentioning

confidence: 99%

Precipitation of Asphaltenes and Resins at the Toluene–Silica Interface: An Example of Precipitation Promoted by Local Electrical Fields Present at the Silica–Toluene Interface

2014

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“…The model parameters summarized in Table were obtained by minimizing the average square deviations between the experimental data and the model. The coefficient of determination, R 2 , suggests that the data are better fit by Langmuir model, which entails monolayer adsorption. − It should be noted that values of the coefficient of determination, R 2 , are very low for the Freundlich isotherm fitting, as opposed to Langmuir fit, which was always high, >0.96. Accordingly, Langmuir isotherm was assumed.…”

Section: Results and Discussionmentioning

confidence: 99%

Asphaltenes Adsorption onto Metal Oxide Nanoparticles: A Critical Evaluation of Measurement Techniques

2018

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The adsorption of asphaltenes onto nanoparticles (NPs) has received a lot of attention in recent years. However, the effect of the measurement technique on the adsorption isotherms has never been addressed. In this paper, the adsorption of n-heptane-precipitated asphaltenes, C7-asphaltenes, from toluene model solutions onto three metal oxide NPs, namely Fe2O3, Fe3O4, and Al2O3, was studied. Asphaltenes uptake calculated from UV–vis spectroscopy at three different wavelengths were compared with thermogravimetric analysis (TGA) results. Although the adsorption trends followed Langmuir isotherms, instrument as well as wavelength-dependent coefficients were obtained. We believe TGA results are more reliable, provided complete oxidation and account of mass loss due to NPs is attained. UV–vis measurements may be impacted by the chemical structure of the asphaltenes sub fractions as well as their state of association. Al2O3 showed the highest adsorption capacity of 385 ± 5 mg/g, followed by Fe3O4 and Fe2O3. However, based on mg/m2, Fe2O3 displayed the highest adsorption capacity. TGA analysis revealed that the NPs promoted the oxidation of adsorbed asphaltenes in a reverse order to their adsorption capacity, q max (mg/g) (Al2O3 > Fe2O3 ≈ Fe3O4). This trend is in line with our previous observation of mass-dependent thermo-oxidative profile and surface exposure role, rather than a catalyst role, of the NPs. Lastly, the C7-asphaltenes from this study were characterized, and their structural parameters were compared to 45 asphaltenes from the literature. The size and structural parameters of the asphaltenes clusters are in good agreement with the literature values.

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“…As a result, both monolayer [19][20][21][22][23][24][25] and multilayer [22,[26][27][28] adsorption behavior have been reported, depending on the solvent and source of asphaltenes used in experiments. Acevedo et al [29] studied the adsorption of asphaltenes onto silica particles and adsorption of resins onto asphaltene particles using ultraviolet spectroscopy method.…”

Section: Introductionmentioning

confidence: 98%

Genetic Algorithm Development for Prediction of Modified Langmuir Isotherm Parameters of Asphaltene Adsorption onto Metal Surfaces: Using Novel Quartz Crystal Nanobalance

Mohammadi

Sedighi

Kiasari

et al. 2014

Journal of Dispersion Science and Technology

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Asphaltene deposition is a common problem in production operation; these problems cause obstruction through pore throats, production tubing, and also surface facilities. In this article, adsorption of asphaltene, obtained from a crude oil sample from Iranian southern oil fields, onto metal surfaces has been extensively investigated. The metal surfaces are aluminum, iron, and copper. The amount of adsorbed asphaltene was successfully measured with a novel method named as quartz crystal nanobalance. To model the prediction of asphaltene adsorption onto metal surfaces, a concentration dependent factor, X, was introduced. To account for the exact asphaltene concentration effect on both adsorption and desorption steps, the modified Langmuir isotherm was developed. Genetic algorithm was used to optimize the set of unknown parameters. The results indicated that good agreement was between model results for different metal surfaces and experimental data.

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The Prediction of Asphaltene Adsorption Isotherm Constants on Mineral Surfaces

Cited by 15 publications

References 28 publications

Precipitation of Asphaltenes and Resins at the Toluene–Silica Interface: An Example of Precipitation Promoted by Local Electrical Fields Present at the Silica–Toluene Interface

Precipitation of Asphaltenes and Resins at the Toluene–Silica Interface: An Example of Precipitation Promoted by Local Electrical Fields Present at the Silica–Toluene Interface

Asphaltenes Adsorption onto Metal Oxide Nanoparticles: A Critical Evaluation of Measurement Techniques

Genetic Algorithm Development for Prediction of Modified Langmuir Isotherm Parameters of Asphaltene Adsorption onto Metal Surfaces: Using Novel Quartz Crystal Nanobalance

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