Effect of the Chemical Composition of Soil Humic Acids on Their Viscosity, Surface Pressure, and Morphology

Nègre, Michéle; Vindrola, Daniela; Spera, Silvia; Ferraris, Lucia; Gennari, Mara

doi:10.1097/00010694-200210000-00002

Cited by 25 publications

(16 citation statements)

References 53 publications

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“…This was taken to be evidence for the humiclike character of the polyacidic fraction. It also corresponds to the general rule that higher polarity molecules (e.g., monoand di-carboxylic acids) have a greater affinity for the bulk solution and hence reduced surface-active properties (Negre et al, 2002).…”

Section: Surface and Colloidal Propertiesmentioning

confidence: 68%

“…Considering its possible importance to atmospheric chemistry, the colloidal nature of HULIS deserves more study. Based on data for humic substances Yates and von Wandruszka, 1999;Negre et al, 2002), it can be suggested that at relevant atmospheric pH values (3-6 pH units; Facchini et al, 1999), the surface tension lowering capacity of HULIS may be at its greatest.…”

Section: Surface and Colloidal Propertiesmentioning

confidence: 99%

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Atmospheric HULIS: How humic-like are they? A comprehensive and critical review

2006

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Abstract.A class of organic molecules extracted from atmospheric aerosol particles and isolated from fog and cloud water has been termed HUmic-LIke Substances (HULIS) due to a certain resemblance to terrestrial and aquatic humic and fulvic acids. In light of the interest that this class of atmospheric compounds currently attracts, we comprehensively review HULIS properties, as well as laboratory and field investigations concerning their formation and characterization in atmospheric samples. While sharing some important features such as polyacidic nature, accumulating evidence suggests that atmospheric HULIS differ substantially from terrestrial and aquatic humic substances. Major differences between HULIS and humic substances, including smaller average molecular weight, lower aromatic moiety content, greater surface activity, better droplet activation ability, as well as others, are highlighted. Several alternatives are proposed that may explain such differences: (1) the possibility that mono-and di-carboxylic acids and mineral acids abundant in the atmosphere prevent the formation of large humic "supramolecular associations"; (2) that large humic macromolecules are destroyed in the atmosphere by UV radiation, O 3 , and OH − radicals; 3) that "HULIS" actually consists of a complex, unresolved mixture of relatively small molecules rather than macromolecular entities; and (4) that HULIS formed via abiotic and short-lived oxidative reaction pathways differ substantially from humic substances formed over long time periods via biologically-mediated reactions. It should also be recalled that the vast majority of studies of HULIS relate to the water soluble fraction, which would include only the fulvic acid fraction of humic substances, and exclude the humic acid (base-soluble) and humin (insoluble) fractions of humic substances. A significant effort towards Correspondence to: E. R. Graber (ergraber@volcani.agri.gov.il) adopting standard extraction and characterization methods is required to develop a better and meaningful comparison between different HULIS samples.

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Section: Surface and Colloidal Propertiesmentioning

confidence: 68%

Section: Surface and Colloidal Propertiesmentioning

confidence: 99%

Atmospheric HULIS: How humic-like are they? A comprehensive and critical review

2006

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“…The term amphiphilic substances describes molecules formed by both, hydrophobic and hydrophilic functional groups (Morrison and Boyd, 1983), which altogether may affect the actual wettability of soils (Franco et al, 2000). Soil organic matter (OM) consists of amphiphilic components; therefore, Negre et al (2002) linked the ability of water to spread on a soil surface to the macromolecular composition of OM. In consequence, the wetting behaviour of soils may change with the content and composition of OM coatings on mineral particle surfaces (Leue et al, 2010) as well as the spatial arrangement of OM compounds at the molecular scale (Morrison and Boyd, 1983).…”

Section: Introductionmentioning

confidence: 99%

Quantity of Hydrophobic Functional CH-Groups – Decisive for Soil Water Repellency Caused by Digestate Amendment

Voelkner¹,

Holthusen²,

Ellerbrock³

et al. 2015

International Agrophysics

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Anaerobic digestates are used as organic fertilizers; however, they are suspected to interfere negatively with soils. To investigate the relevance of the anaerobic digestates composition on potential wettability and contact angle of the soil, we mixed in a laboratory experiment 30 m³ ha-1 of anaerobic digestates derived from mechanically pre-treated substrates from maize and sugar beet with a homogenized Cambic Luvisol. Fourier transform infrared-spectra and diffuse reflectance infrared Fourier transform-spectra of particle intact and finely ground soilanaerobic digestates-mixtures were analyzed to determine the quantities of hydrophobic functional groups in the soil-anaerobic digestates-mixtures that are used here as an indicator for the potential hydrophobicity. The anaerobic digestates application increased the amount of hydrophobic functional groups of the mixtures and reduced the wettability of the soil. However, for intact particle samples an up to threefold higher amount of hydrophobic groups was found as compared to the finely ground ones, indicating a dilution effect of mechanical grinding on the effectivity of the organic matter that is presumably located as a coating on mineral soil particles. For the particle intact samples, the intensity of hydrophobic functional groups bands denoting hydrophobic brickstones in organic matter is indicative for the actual wettability of the soil-anaerobic digestates-mixtures.

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“…Dentro dessa ótica, os resultados de pesquisas confirmam que a persistente estabilização dos agregados é devida a mineralogia do solo, ao aumento da fração de matéria orgânica estável, semelhante às substâncias húmicas, e que a menor acidez e a maior fração húmica hidrofóbica são responsáveis pela estabilidade dos agregados (PICCOLO e MBAGWU, 1990;BRADFORD e BLANCHAR, 1999;NOVOTNY et al, 1999;NÈGRE et al, 2002).…”

Section: Tendências Futuras Para O Estudo Da Incisão Em Canais Com Maunclassified

“…De maneira semelhante, as leis da hidráulica que governam o movimento de partículas, sem coesão, em BLANCHAR, 1999;PICCOLO, 1996;DeBANO, 2000;NOVOTNY, et al 1999;NÈGRE et al, 2002), podem esclarecer algumas discrepâncias, encontradas por pesquisadores, sobre a resistência do solo superficial.…”

Section: Tendências Futuras Para O Estudo Da Incisão Em Canais Com Maunclassified

Modelagem De Canais Incisivos - Revisão

Quadros¹,

Wisniewski²,

Passos³

2004

Ra'e Ga

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1 O presente trabalho foi realizado como o apoio do Conselho Nacional de Desenvolvimento Científico e Tecnológico -CNPq -Brasil. 2 ruth-maria.quadros@mma.gov.br, Secretaria de Recursos Hídricos/MMA, SGAN 601, lote 1, Brasília-DF. 3 cewisni@agrarias.ufpr.br, professora, DSEA -UFPR, R. dos Funcionários, 1540 -80035-050, Curitiba-PR 4 everton@ufpr.br, UFPR RESUMOO objetivo deste artigo é documentar as mais importantes pesquisas e aspectos histórico-cronológicos sobre a modelagem da incisão de canais. São apresentados os aspectos qualitativos e quantitativos envolvidos, desde a dedução das equações de Saint-Venant e de Exner, até as mais recentes pesquisas sobre o alargamento e o deslizamento das margens dos canais, considerando a coesão das mesmas. Do ponto de vista quantitativo, ainda há muitos processos importantes a serem solucionados, com destaque para os mecanismos envolvidos na desagregação e transporte de partículas de solo coesivas. Pesquisas recentes mostram que a estimativa da desagregação pelos métodos tradicionais de determinação da resistência do solo pode não ser a mais recomendada para avaliar a resistência na interface solo-água. Isto aponta para a importância dos processos físico-químicos envolvidas na estabilidade das partículas do solo e, conseqüentemente, na sua suscetibilidade à erosão, assim como a importância da sua representação matemática e inclusão na modelagem do processo de incisão de canais. Palavras-chave:Sulco, voçoroca, desagregação, estabilidade de agregados, erosão. ABSTRACTThis paper aims at documenting some of the more important research and historical-chronological aspects concerning incised channels modelling. Qualitative and quantitative aspects are presented, beginning with the deduction of the Saint-Venant and Exner equations and going through the more recent equations explaining the enlargement and stability of cohesive riverbanks. From a quantitative point of view, there are still many important processes to be solved, specially those regarding detachment mechanisms and transport of cohesive soil aggregates. Recent research has shown that soil evaluation aggregates detachment by conventional methods (soil strength determination) cannot measure the properties at the soil-water interface with the necessary resolution. These results allow visualizing the importance of the physicochemical mechanisms involved on aggregate stability at the soil-water interface; and, consequently, its degradation suscetibility. These mechanisms should be mathematically described and included in incised channel modeling.

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Effect of the Chemical Composition of Soil Humic Acids on Their Viscosity, Surface Pressure, and Morphology

Cited by 25 publications

References 53 publications

Atmospheric HULIS: How humic-like are they? A comprehensive and critical review

Atmospheric HULIS: How humic-like are they? A comprehensive and critical review

Quantity of Hydrophobic Functional CH-Groups – Decisive for Soil Water Repellency Caused by Digestate Amendment

Modelagem De Canais Incisivos - Revisão

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