COMPLEXATION OF RADIONUCLIDES WITH HUMIC SUBSTANCES

摘要

Humic substances are ubiquitous compounds presenting specific properties with respect to complexation, sorption and transport. Because they may enhance metal solubilities due to their strong complexing properties, as well as increase or decrease metal retention on mineral surfaces due to their affinity for mineral substrates and their scavenging properties, humic substances may impact metal speciation in the environment, and in particular radionuclides speciation. Various examples based on actinides, lanthanides or iodine will be presented to illustrate the complexation properties as well as speciation calculations with emphasis on the thermodynamic constants used and the techniques used to obtain them.