Polyelectrolytes, natural organic

Humic acids (HA) and fulvic acids (FA) are the main components of humic substances (HS), which are the most chemically and biochemically active and widely spread fractions of nonliving natural organic matter in all terrestrial and aquatic environments. They comprise a chemically and physically heterogeneous group of substances with colloidal, polydis-persed, polyelectrolyte characteristics and mixed aliphatic and aromatic nature (Senesi and Loffredo 1999). 

Kilduff, J. E., T. Karanfil, Y. P. Chin, and W. J. Weber. 1996. Adsorption of natural organic polyelectrolytes by activated carbon A size-exclusion chromatography study. Environmental Science and Technology 30 1336. 

Ephraim, J. H., Alegret, S., Mathuthu, A., Bicking, M., Malcom, R.L., and Marinsky, J. A. (1986). A unified physicochemical description of the protonationandmetal ion complex-ation equilibria of natural organic acids (humic and fulvic acids). 2. Influence of polyelectrolyte properties and functional group heterogeneity on the protonation equilibria of fulvic acid. Environ. Sci. Technol. 20, 354-366. 

T. Carroll, N. A. Booker, and J. Meier-Haack, Polyelectrolyte-grafted microfiltration membranes to control fouling by natural organic matter in drinking water. Journal of Membrane Science 203, 3-13 (2002). 

The focus here is on the effects of dissolved natural organic matter (NOM) on the colloidal stability of particles in aquatic systems and, in particular, on the importance of the macromolecular nature of NOM in these effects. The approach used here has three components (1) modeling studies with mathematical polyelectrolytes, surfaces, and solvents (2) laboratory studies with well-characterized polyelectrolytes and particles and (3) laboratory studies with aquatic NOM, also using well-characterized particles. 

Wershaw, R. L. and Goldberg, M. C. (1972). Interaction of organic pesticides with natural organic polyelectrolytes. In Fate of Organic Pesticides in the Aquatic Environment, Advances in Chemistry Series III (S. D. Faust, ed.). American Chemical Society, Washington, D.C., pp. 149-158. 

Kilduff, J.E., Karanfil, T., Chin, Y.P, and Weber, W., Jr (1996). Adsorption of natural organic polyelectrolytes by activated carbon a size exclusion study. Environ. Sd. Technol, 30(4), 1336-46. 

Interaction of Organic Pesticides with Natural Organic Polyelectrolytes... 

Natural organic polyelectrolytes are some of the most active components of natural soil-water systems entering into physical and chemical reactions with practically all other components of the systems. Most pesticides are strongly sorbed by insoluble natural organic polyelectrolytes, such as humic acid. The soluble humic salts, however, may solubilize insoluble pesticides. Pesticides also enter into chemical reactions with natural organic poly electrolytes. The mechanisms of most of these interactions have not yet been elucidated. Elucidation will require isolation of well-defined, chemically and physically homogeneous natural polyelectrolyte fractions. 

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