Competitive complexation of metal ions with humic substances.

The surface complexation model was applied to simulate the competitive complexation of Ni, Ca and Al with humic substances. The presence of two types of binding sites in humic acid, carboxylic and phenolic functional groups, were assumed at both low and high pH conditions. Potentiometric titrations were used to characterize the intrinsic acidity constants of the two binding sites and their concentrations. It was found that the diffuse-layer model (DLM) could fit the experimental data well under different experimental conditions. Ni and Ca ions strongly compete with each other for reactions with the humic acid but Al showed little influence on the complexation of either Ni or Ca due to its hydrolysis and precipitation at pH approximately 5. The surface complexation constants determined from the mono-element systems were compared with those obtained from the multiple-element system (a mixture of the three metal ions). Results indicate little changes in the intrinsic surface complexation constants. Modeling results also indicate that high concentrations of Ca in the contaminated groundwater could strongly inhibit the complexation of Ni ions whereas an increase in pH and the humic concentration could attenuate such competitive interactions. The present study suggests that the surface complexation model could be useful in predicting interactions of the metal ions with humic substances and potentially aid in the design of remediation strategies for metal-contaminated soil and groundwater.

[1]  D. Lovley,et al.  Humic Substances as a Mediator for Microbially Catalyzed Metal Reduction , 1998 .

[2]  G. D. Turner,et al.  Models for Association of Metal Ions with Heterogeneous Environmental Sorbents. 1. Complexation of Co(II) by Leonardite Humic Acid as a Function of pH and NaClO4 Concentration. , 1995, Environmental science & technology.

[3]  J. Mejuto,et al.  Enhancement of copper and cadmium adsorption on kaolin by the presence of humic acids. , 2002, Chemosphere.

[4]  F. J. Stevenson.  HUmus Chemistry Genesis, Composition, Reactions , 1982 .

[5]  C. Calmon,et al.  Book reviewHumic substances in soil, sediment and water: by G.R. Aiken, D.M. McKnight, R.L. Wersham and P. McCarthy (Eds.), John Wiley and Sons, New York, 1985, xiii + 692 pages, $59.95 , 1986 .

[6]  D. Kinniburgh,et al.  Analysis of metal-ion binding by a peat humic-acid using a simple electrostatic model. , 1995 .

[7]  J. Allison,et al.  MINTEQA2/PRODEFA2, a geochemical assessment model for environmental systems: Version 3. 0 user's manual , 1991 .

[8]  A. Davis,et al.  Removal of Cu(II) and Cd(II) from aqueous solution by seafood processing waste sludge. , 2001, Water research.

[9]  J. Banfield,et al.  Microbial Populations Stimulated for Hexavalent Uranium Reduction in Uranium Mine Sediment , 2003, Applied and Environmental Microbiology.

[10]  E. Tipping,et al.  Cation binding by humic substances: Cation–humic binding and other physico-chemical processes , 2002 .

[11]  R. Kretzschmar,et al.  Interaction of copper and fulvic acid at the hematite-water interface , 2001 .

[12]  E. LeBoeuf,et al.  Macromolecular characteristics of natural organic matter. 2. Sorption and desorption behavior. , 2000 .

[13]  Scott Fendorf,et al.  Inhibition of bacterial U(VI) reduction by calcium. , 2003, Environmental science & technology.

[14]  B. Honeyman,et al.  Uranium (VI) sorption to hematite in the presence of humic acid , 1999 .

[15]  Janet G. Hering,et al.  Principles and Applications of Aquatic Chemistry , 1993 .

[16]  F. Monteil-Rivera,et al.  Acid/base and Cu(II) binding properties of natural organic matter extracted from wheat bran: modeling by the surface complexation model. , 2000 .

[17]  J. Wit,et al.  Proton binding to humic substances. 1. Electrostatic effects , 1993 .

[18]  Marmier,et al.  Sorption of Cs(I) on Magnetite in the Presence of Silicates. , 2000, Journal of Colloid and Interface Science.

[19]  C. Gérente,et al.  Modeling of single and competitive metal adsorption onto a natural polysaccharide. , 2002, Environmental science & technology.

[20]  Edward R. Landa,et al.  Microbial reduction of uranium , 1991, Nature.

[21]  F. Morel,et al.  Surface Complexation Modeling: Hydrous Ferric Oxide , 1990 .

[22]  David G. Kinniburgh,et al.  Metal ion binding by humic acid : Application of the NICA-Donnan model , 1996 .

[23]  John M. Zachara,et al.  Microbial Reduction of Crystalline Iron(III) Oxides: Influence of Oxide Surface Area and Potential for Cell Growth , 1996 .

[24]  D. Langmuir.  Aqueous Environmental Geochemistry , 1997 .

[25]  L. Charlet,et al.  The Acid/Base Chemistry of Montmorillonite , 1994 .

[26]  Jacques Buffle,et al.  Complexation reactions in aquatic systems , 1988 .

[27]  W. D. Burgos,et al.  Enhancement of biological reduction of hematite by electron shuttling and Fe(II) complexation. , 2002, Environmental science & technology.

[28]  M. McBride.  Environmental Chemistry of Soils , 1994 .

[29]  S. Brooks,et al.  Geochemical reactions and dynamics during titration of a contaminated groundwater with high uranium, aluminum, and calcium , 2003 .

[30]  F. Monteil-Rivera,et al.  Metal Ions Binding to Natural Organic Matter Extracted from Wheat Bran: Application of the Surface Complexation Model. , 2000, Journal of colloid and interface science.

[31]  B. Gu,et al.  Enhanced microbial reduction of Cr(VI) and U(VI) by different natural organic matter fractions , 2003 .

[32]  David R. Anderson,et al.  Distance Sampling: Estimating Abundance of Biological Populations , 1995 .

[33]  R. Gonzalez,et al.  Modeling adsorption of copper(II), cadmium(II) and lead(II) on purified humic acid , 2000 .

[34]  N. Pind,et al.  Nickel Adsorption on MnO2, Fe(OH)3, Montmorillonite, Humic Acid and Calcite: A Comparative Study , 1997 .

[35]  Jinho Jung,et al.  COMPARATIVE STUDY OF CU2+ ADSORPTION ON GOETHITE, HEMATITE AND KAOLINITE :MECHANISTIC MODELING APPROACH , 1998 .

[36]  D. Kinniburgh,et al.  Humic matter and contaminants. General aspects and modeling metal ion binding , 2001 .

[37]  M. E. Essington,et al.  Adsorption of mercury(II) by kaolinite , 2000 .

[38]  J. McCarthy,et al.  Adsorption and desorption of natural organic matter on iron oxide: mechanisms and models. , 1994, Environmental science & technology.

[39]  B. Allard,et al.  Effects of a fulvic acid on the adsorption of mercury and cadmium on goethite. , 2003, The Science of the total environment.

[40]  Ikhsan,et al.  A Comparative Study of the Adsorption of Transition Metals on Kaolinite. , 1999, Journal of colloid and interface science.

[41]  L. Figueroa,et al.  Modeling Reduction of Uranium U(VI) under Variable Sulfate Concentrations by Sulfate-Reducing Bacteria , 2000, Applied and Environmental Microbiology.