BEHAVIOUR OF HUMIC ACIDS IN WATER AND AQUEOUS SOLUTIONS

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Behaviour of various humic samples in water and aqueous solutions is studied in this chapter. Although humic acids are operationally defined as that fraction of humic substances, which is not soluble under acidic conditions, it does not mean that the solid preparation easily dissolves in water. Presented results suggest that dissolving of solid humic acids in water environment is more complex than conventional solubility behaviour of sparingly soluble solids. Multi-step mechanism of solid humic acids interaction with water, including partial equilibrium dissolution as well as direct equilibrium dissociation from the solid state, was proposed and proved experimentally. Only a very small part of solid humic acids can be dissolved in water and not giving necessarily saturation at the same time. Washing out experiments show that only a certain maximum of soluble fraction can exist in all used humic samples. Other experiments confirm that the dissolution of humic particles is significantly affected by the presence of carboxylic acids. The results indicate that the acids and related compounds may affect markedly the mobility and transport of humic substances in the environment. Experimental data further demonstrate that regardless the common mechanism, solubility and dissociation degree of various humic samples may be very different and can be estimated using the parameters of model based on the proposed mechanism.

humic acid, dissociation, solubility, polyelectrolytes

KLUČÁKOVÁ, M.; ČECHOVÁ, E.; BACHRATÁ, R.; PEKAŘ, M.

2010

18. 11. 2010

Nova Science Publishers, Inc.

New York

978-1-60741-761-3

Solid Waste Management and Environmental Remediation

Environmental Remediation: Regulatory Requirements, Site Assessment and Health Effects

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