Reactivity and transport properties of metal ions in humic systems are important both for understanding role of humic substances in natural systems and human-driven applications. This work is focused on Cu(II) ions transport and immobilization in hydrogels based on several humic acids differing in isolation conditions and raw materials. Prepared humic gels contained different amounts of reactive functional groups (with different affinity to metal ions) in order to study an effect of structurev and properties of humic acids and selective blocking of carboxylic groups (by methylation) on the mobility and immobilization of Cu(II) ions in gel structure. The experimental arrangement was selected to enable an instantaneous planar source method for data processing based on the determination of concentration distribution of Cu(II) ions in hydrogels. The resulting values of effective diffusion coefficient include both the effect of hydrogels structure and the effect of the reaction between Cu(II) ions and humic acids. The blocking of functional groups reflected in a lower values of diffusivity in comparison to the gels prepared from unmodified humic acids. There was also confirmed the effect of isolation procedure of humic acids and their properties on the diffusivity of Cu(II) ions in hydrogels.
