The surface activity of humic acid

Tschapek, M.; Wasowski, C.

doi:10.1016/0016-7037(76)90123-x

Cited by 53 publications

(16 citation statements)

References 4 publications

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“…It has been shown ( Tschapek et al, 1978) that probably all soil water contains molecules with an amphiphilic structure; because the surface tension of soil water is always lower than that of pure water. The magnitude of the decrease in surface tension depends on the quantity of organic matter and on pH, and is close to 10mNm-l in the case of normal soils, while in soils with peptized humic acid it can be as high as 40 mNm-' (Tschapek and Wasowski, 1976).…”

Section: Schreiner Andmentioning

confidence: 76%

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Criteria for Determining the hydrophilicity‐hydrophobicity of Soils

Tschapek

1984

J Plant Nutrition & Soil

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Except for dehydroxylated silica, all the inorganic minerals of soils are hydrophilic because their surfaces usually hold ions and polar groups (hydroxyls). The molecules of humic acid, i. e. the most important part in soil humus, are amphiphilic and superficially active. Water repellancy in soils is mainly caused by amphiphilic humic acid. Criteria are supplied to characterize the hydrophilic‐hydrophobic balance of soils. The changes in the hydrophilicity‐hydrophobicity of soil by the addition of organic components modify many of their hydric properties, such as wetting, evaporation, infiltration, etc. which are frequently incompatible. Due to the many different types of soil and organic correctors, no general recommendations can be made.

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Section: Schreiner Andmentioning

confidence: 76%

“…The aliphatic alcohol (1-heptanol) adsorbs selectively from water to the dehydroxylated silicate ( Tschapek and Wasowski, 1976;Tschapek et al, 1979), showing that hydrophilicity is decreased, i. e. shows the presence of hydrophobic sites.…”

Section: Hydrophilicity-hydrophobicity Of Inorganic Components In Soilmentioning

confidence: 99%

Criteria for Determining the hydrophilicity‐hydrophobicity of Soils

Tschapek

1984

J Plant Nutrition & Soil

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“…Humic acids are surface active, significantly lowering the surface tension of water (11)(12)(13)(14)(15). Both Tshapek and Wasowski (16) and Rochus and Sipos (13) have attempted to measure critical micelle concentrations (CMC) for several different humic and fulvic acids.…”

Section: Properties Of Humic Acidmentioning

confidence: 99%

Application of a membrane model to the sorptive interactions of humic substances.

Wershaw

1989

Environ Health Perspect

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Humic substances, the dark-colored, natural organic polyelectrolytes that are found in practically all soils, sediments, and natural water, strongly interact with both inorganic and organic pollutants. Inorganic cationic species generally undergo complexation reactions with humic substances. The binding of cations, such as cupric ions, by humic substances often markedly reduces their toxicity to aquatic organisms. Some inorganic anionic species, in the presence of metal ions, are sorbed by humic substances. In these instances the metal ions appear to form bridges between the humic substances and the anions. Several different types of interactions take place between organic compounds and humic materials. Hydrophobic organic species partition into either insoluble or soluble humic substances. The insoluble humic substances will remove hydrophobic organic compounds from the aqueous phase, thereby rendering them less mobile. However, soluble humic substances will solubilize hydrophobic organics, increasing their mobility. Other types of interactions between humic substances and organic compounds, such as adsorption and ion exchange, also have been observed. These various interactions between humic substances and pollutants are important in governing their fate and movement in natural water systems, and, for this reason, a detailed understanding of the mechanisms of the interaction is important. A recently developed membrane model of the structure of humic substances is described; this model enables one to better understand the physical-chemical properties of these materials.ImagesFIGURE 2.FIGURE 3.

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“…It has long been recognised that SOM, dissolved in water, can display surface activity (Hayase 1992;Tschapek and Wasowski 1976;Yates and von Wandruszka 1999) as a direct consequence of its molecular composition which combines both hydrophilic and hydrophobic moieties. Observed manifestations of surface activity include surface tension reduction (Terashima et al 2004) and the formation of micelle-like aggregates (Guetzloff and Rice 1994;von Wandruszka et al 1997;Wershaw 1986).…”

Section: Soil Organic Matter Transfer To the Aqueous Phasementioning

confidence: 99%

Aqueous Solution of Anionic Surfactants Mixed with Soils Show a Synergistic Reduction in Surface Tension

Hagenhoff¹,

Dong²,

Chowdhry³

et al. 2009

Water Air Soil Pollut

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Water retention and transport in soils is dependent upon the surface tension of the aqueous phase. Surfactants present in aqueous solution reduce the surface tension of aqueous phase. In soil-water systems, this can result in water drainage and reductions in field capacity and hydraulic conductivity. In this investigation, the surface tension of surfactant solutions mixed with soil-in a constant fixed ratio-was measured as a function of surfactant concentration. Two anionic surfactants were used: sodium dodecyl sulphate and sodium bis (2-ethylhexyl) sulfosuccinate. Two soils were also used-a clay soil and a sandy soil. The key observation made by this investigation was that the addition of soil to the surfactant solution provided a further component of surface tension reduction. Neither soil sample reduced the surface tension of water when surfactant was absent from the aqueous phase, though both soils released soil organic matter at low surfactant concentrations as shown by measurement of the chemical oxygen demand of the supernatant solutions. Furthermore, both surfactants were shown to be weakly adsorbed by soil as shown by the use of a methylene blue assay. It is therefore proposed that the additional reduction in surface tension arises from synergistic interactions between the surfactants and dissolved soil organic matter.

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The surface activity of humic acid

Cited by 53 publications

References 4 publications

Criteria for Determining the hydrophilicity‐hydrophobicity of Soils

Criteria for Determining the hydrophilicity‐hydrophobicity of Soils

Application of a membrane model to the sorptive interactions of humic substances.

Aqueous Solution of Anionic Surfactants Mixed with Soils Show a Synergistic Reduction in Surface Tension

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