Computer simulation of metal ion—humic and fulvic acid interactions

The humate model, RANDOM, was investigated in combination with the general speciation program, PHREEQE. After an initial investigation of cobalt(II)–humic acid and copper(II)–fulvic acid interactions this coupled code approach was modified to include a sensitivity analysis which identified the ligands which were statistically significant in any one system. Subsequent speciation modelling with these significant ligands is shown to produce a reasonable agreement between experimental and modelled data. The systems chosen to demonstrate the advantages of this approach were uranyl–humate and nickel(II)–humate interactions. Although this technique is not fully developed, it shows great potential for improving the predictive qualities of the RANDOM model.