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Hydrolysis of dimetilan is used to examine the synergistic effects of metal ions and organic ligands on the degradation of agricultural chemicals.

Results revealed that carboxyl groups are the main factors that govern the metal binding by the Datura innoxia biomass. Other functionalities, however, are also responsible for the metal binding by the biomass. The continued increase in the measured amount of methanol released suggest that methyl etherification of hydroxuls on the biomass could have also occurred. It is inferred that the binding capacity of the biomass is reduced as esterification is increased.

A model for ion binding to humic substances was developed through the combination of the non-ideal competitive adsorption (NICA) model for specific binding of electrolyte ions with a Donnan-type model for nonspecific binding. The resulting NICA-Donnan model was applied to data for H, Ca, Cd, Cu and Pb binding by a purified peat humic acid. Predictions of the competitive effect of Ca on Cd and Cu binding at various pHs were consistent with experimental data, except for some small differences. The increase in Cd and Cu binding on changing from a 0.1 M KNO3 background electrolyte to 0.01 M KNO3 was also predicted well by the NICA-Donnan model.

An approach to modeling the binding of heavy metal ions and protons was developed to improve the prediction of the effect of protons as exchanged species on proton-metal ion binding. Biosorption was observed in the algal biomass of Sargassum fluitans. The mechanism of metal ion binding in this biomass is discussed.

Metal release processes are described in terms of subsurface environment chemical conditions. The study used goethite as a sorptive base for its metal ion sorption ability. pH adsorption isotherms for picolinic and nicotinic acid were observed with similar results compared with other carboxylic acids. Manganese yielded the greatest fractional percentage for adsorption, while copper, nickel, cobalt and lead generated similar results.

The stability of mixed-ligand complexes of metal ions with humic substances and low molecular weight ligands is investigated. It is shown that the fraction of metal bound to humic substances in a system can be modeled better if mixed-ligand complexes are also included. However, mixed-ligand complexes of the type MSLi are innately weak as compared to complexes with low molecular weight ligands.

Metal binding sites on soil fulvic acid (FA) were investigated. Specifically, luminescence spectroscopy was employed to obtain the 7F0-5D0 transition spectra of solutions of Eu(III) and soil FA at 2.9-7.8 pH levels and FA concentrations of 800-3,200 mg/L. The resulting asymmetric excitation spectra is compared to the sum of two Lorentzian-shaped curves. This highlighted the presence of two kinds of carboxylate moieties for metal ion binding on FA.

New analytical methods for examining metal speciation using Chelex cation exchange resin are described. Specific appliciations of these methods for the study of the speciation of lead, copper and cadmium are also provided. Chemical speciation of these three trace metals is studied using samples of river water and snow. Results show that uptake of these trace metals is influenced by the presence of the complexants fulvic acid, NTA and EDTA.

Eu(super 3+) luminescence spectroscopy was employed in a study of the binding interactions between metal ions and bits of Datura innoxia cell walls. The results showed complete metal ion binding occured when the pH is greater than or equal to five. The affinity order was Cu(super 2+) and Ag(super +) > Ni(super 2+) > Cd(super 2+) > Eu(super 3+) > Sr(super 2+) > Ba(super 2+).

The effects of pH, solution chromium concentrations and surface coverage on the surface structure of chromium(III) sorbed on amorphous silica were studied to determine how various reaction conditions affect the stability of chromium(III) bound to a sorbent. The study protocol involved diffuse reflectance infrared Fourier transform spectroscopy and high-resolution transmission electron microscopy. Results showed that the extent of surface coverage alone affected the atomic structure of chromium sorbed on silica.

The surface structure of chromium(III) (CrIII) sorbed on silica was studied using extended X-ray absorption fine structure spectroscopy to improve the understanding of metal ion interactions at the solid-solution interface. The structural environment of metal ions at the solid-solution interface determines ion remobilization to the solution and the physical and chemical changes of the sorbent. Results showed that Cr(III) forms a monodentate surface complex on silica. Cr-Si and Cr-Cr distances were obtained, with the latter indicating edge-sharing Cr octahedra.