WETTABILITY OF MONTMORILLONITE CLAYS IN HUMIC ACID SOLUTIONS

2003 ◽  
Vol 51 (1) ◽  
pp. 65-74 ◽  
Author(s):  
Juan de Dios García López-Durán ◽  
Asmae Khaldoun ◽  
Mohamed Larbi Kerkeb ◽  
María del Mar Ramos-Tejada ◽  
Fernando González-Caballero
Keyword(s):  
Humic Acid ◽  
Acid Solutions ◽  
Montmorillonite Clays

scholarly journals Temperature Induced Aggregation and Clouding in Humic Acid Solutions

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Leah Shaffer ◽  
Ray von Wandruszka
Keyword(s):  
Aqueous Solution ◽  
Light Scattering ◽  
Humic Acid ◽  
Dynamic Light Scattering ◽  
Acid Solutions ◽  
Inverse Temperature ◽  
Mechanical Agitation ◽  
Coulombic Repulsion ◽  
Polarity Sensitive ◽  
Induced Aggregation

Humic acids in aqueous solution demonstrate inverse temperature-solubility relationships when solution conditions are manipulated to reduce coulombic repulsion among the humic polyanions. These effects were followed by dynamic light scattering (DLS) measurements of the resulting aggregates, as well as the addition of a polarity sensitive fluorescent probe (pyrene). The humic solutions could be primed for temperature induced clouding by carefully lowering the pH to a point where hydration effects became dominant. The exact value of the cloud point (CP) was a function of both pH and humate concentration. The CPs mostly lay in the range 50–90°C, but DLS showed that temperature induced aggregation proceeded from approximately 30°C onward. Similar effects could be achieved by adding multivalent cations at concentrations below those which cause spontaneous precipitation. The declouding of clouded humate solutions could be affected by lowering the temperature combined with mechanical agitation to disentangle the humic polymers.

Size exclusion (radio) chromatography of aqueous humic acid solutions with cesium and strontium

1999 ◽  
Vol 241 (1) ◽  
pp. 37-43 ◽  
Author(s):  
P. Rajec ◽  
P. Gerhart ◽  
F. Macášek ◽  
I. S. Shaban ◽  
P. Bartoš
Keyword(s):  
Humic Acid ◽  
Size Exclusion ◽  
Acid Solutions

Mutagenic activity of chlorinated surface waters and humic acid solutions

1994 ◽  
Vol 4 (1) ◽  
pp. 17-31 ◽  
Author(s):  
P. Venier ◽  
A. Bonaldo ◽  
E. Contiero ◽  
G. Navazio ◽  
A.G. Levis
Keyword(s):  
Humic Acid ◽  
Surface Waters ◽  
Mutagenic Activity ◽  
Acid Solutions

scholarly journals Surface Activity of Humic Acids Depending on Their Origin and Humification Degree

2014 ◽  
Vol 67 (6) ◽  
pp. 493-499 ◽  
Author(s):  
Māris Klaviņš ◽  
Oskars Purmalis
Keyword(s):  
Surface Tension ◽  
Humic Acid ◽  
Humic Acids ◽  
Structural Characteristics ◽  
Acid Solutions ◽  
Solution Ph ◽  
Humic Materials ◽  
Humification Degree ◽  
Surface Active ◽  
The Impact

Abstract Humic substances are able to reduce the surface tension of their solutions and thus can act as surface-active substances in the natural environment, which may have industrial application. The ability to influence the surface tension of humic acid solutions depends on the origin of the humic acids. The objective of this study was comparison of the ability of humic acids of different origin (soil, water, peat, lignite etc.) to influence the surface tension of their solutions, and identification of the structural characteristics of peat humic acids that determine their surfactant properties. Industrially produced humic materials demonstrated no or insignificant impact on the surface tension of their solutions. However, humic acids isolated from peat had significant impact of the surface tension of their solutions, acting as weak surfactants. The surface tension of humic acid solutions decreased with increasing concentration, and depended on solution pH. Using a well-characterised bog profile, the ability to influence the surface tension of peat humic acids was shown to depend on age and humification degree. With increase of the humification degree and age, molecular complexity of humic acids and their ability to influence surface tension decreased; but nevertheless, the impact of the biological precursor (peat-forming bryophytes and plants) could be identified.

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