Water influence on the surfactant adsorption on TiO2

Undesirable adsorption of asphaltenes on rock minerals was studied. Asphaltenes are an important component of crude oil, being also natural surfactant stabilising water/crude oil emulsions. Owing to their chemical nature, asphaltenes are able to associate, form micelles and create a surface charge at the interface. Asphaltenes may be adsorbed on rock reservoir from the organic solvents in crude oil and as an organic colloid, they can adsorb electrolyte ions from aqueous solution. In order to simulate natural conditions we used asphaltenes from local drills, toluene as solvent and several typical oxides and carbonate rock components or minerals as adsorbents. Our study included natural Brazilian quartz, dolomite, calcite and kaolin, as well as pure oxides: Fe 2 O 3 and TiO 2 . The typical shape of asphaltene adsorption isotherms was obtained for all systems studied with the characteristic 'steps' which indicate changes in the state of asphaltene molecules in the solution and at the mineral surface. Those changes are related to the asphaltene association and further formation of hemimicelles and micelles.

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Section: Introductionmentioning

confidence: 99%

Adsorption of asphaltenes from toluene on mineral surface

Marczewski

Szymula

2002

Colloids and Surfaces A: Physicochemical and Engineering Aspect

173

124

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“…Thus, their adsorption on charged mineral surfaces could be considered as adsorption of ionic surfactants. It is well known that the shape of isotherms describing surfactant adsorption process strongly depends on its critical hemimicelle concentration and critical micelle concentration (CMC) which mark the onsets of distinct isotherm regions [31,[54][55][56][57][58]. However, phenomenon of adsorption of natural, not exactly defined surfactant adsorption on not well determined adsorbents-soilsfrom non-polar and weakly polar non-aqueous solutions is largely unexplored.…”

Section: Introductionmentioning

confidence: 99%

Adsorption of asphaltenes from toluene on typical soils of Lublin region

Szymula

Marczewski

2002

Applied Surface Science

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Adsorption of asphaltenes on soils is one of the important problems, though largely underestimated, in environment protection of Lublin region. Asphaltene adsorption properties affect the way the contamination spreads in soil. Analysis of this phenomenon may help in localisation and elimination of oil spills. The asphaltenes studied were obtained from local drills (Ś widnik near Lublin, Poland). In our previous paper, we investigated adsorption of asphaltenes from toluene on rock components (quartz, dolomite, calcite, kaolin as well as pure iron and titanium oxides). In order to simulate the natural oil spill conditions, we used toluene as solvent and typical soils from Lublin region as adsorbents (black earth, peat soil, lessive soil, brown soil, sandy podsolised soil, pararendzina soil). Main physicochemical properties of these soils were reported. Moreover, basic adsorption properties (nitrogen adsorption, adsorption of surfactants from water solutions, acidity, etc.) of several soil fraction were studied. We decided to use only certain mineral fractions with highest adsorption capacity, as other fractions have limited impact on total adsorption. Adsorption on soil fraction gives also some insight into relative importance of various soil components on summary soil properties. The results of adsorption measurements are described in terms of physical adsorption on heterogeneous solids. # 2002 Published by Elsevier Science B.V.

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“…Based on the study above, it is verified that most of the adsorbed gas/condensation was removed by preheating the substrate ( Ref 4,17,19,20,29), and that more intimate contact and higher cooling rate can be obtained, which resulted in a good wetting. Fukumoto and coworkers already noted ( Ref 5,21,22) that the contact property of the splat with substrate surface strongly depends on the wetting of the solid substrate by molten droplet, but not the surface oxidation itself.…”

Section: Discussionmentioning

confidence: 92%

Study of Substrate Preheating on Flattening Behavior of Thermal-Sprayed Copper Particles

et al. 2010

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In this study, the effect of substrate preheating on flattening behavior of thermal-sprayed particles was systematically investigated. A part of mirror-polished AISI304 substrates were preheated to 573 and 773 K for 10 min, and then exposed to an air atmosphere for different durations of up to 48 h, respectively. Contact angle of water droplet was measured on the substrate under designated conditions. It was found that the contact angle increased gradually with the increase of substrate duration after preheating. Moreover, smaller contact angle was maintained on the substrate with higher preheating temperature. Commercially available Cu powders were thermally sprayed onto the substrates with the same thermal treatment history as contact angle measurement using atmospheric plasma-spray technique. The splat shape had a transitional changing tendency from a splash splat to a disk one on the substrate with a short duration after preheating, while reappearance of splash splat with the increase of duration was confirmed. In general, wetting of substrate surface by molten particles may dominate the flattening behavior of thermal-sprayed particles. The occurrence of desorption of adsorbed gas/condensation caused by substrate preheating likely provides good wetting. On the other hand, the poor wetting may be attributed to the re-adsorption of gas/condensation on the substrate surface with the increase of duration. In addition, the shear adhesion strength of coating fabricated on blasted AISI304 substrate was enhanced on the once-heated substrate, but weakened with the increase of duration. The changing tendency of the coating adhesion strength and the wetting of substrate by droplet corresponded quite well with each other.

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Water influence on the surfactant adsorption on TiO2

Cited by 25 publications

References 8 publications

Adsorption of asphaltenes from toluene on mineral surface

Adsorption of asphaltenes from toluene on mineral surface

Adsorption of asphaltenes from toluene on typical soils of Lublin region

Study of Substrate Preheating on Flattening Behavior of Thermal-Sprayed Copper Particles

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