AWWA JAW10721

For this investigation, adsorption isotherm and rate experiments were conducted to study the effects of chemical and physical phenomena on the adsorption of one fulvic acid and two humic acids by three activated carbons. The study focused on the identification and quantification of parameters that affect the adsorption of humic substances by activated carbon and on the application of these findings to water treatment practice. Results demonstrate the dependence of adsorption on pH, initial concentration of humic material, carbon dosage and particle size, and levels of various inorganic ions in solution. Many of the observed effects are attributable to the fact that humic substances are mixtures of compounds and that their adsorption is therefore a multicomponent process. The distribution of adsorptivities within these mixtures appears to vary with the presence of certain ions, most notably Ca2+ and Mg2+. These findings have been applied to bench-scale granular carbon columns and to powdered-carbon slurry systems. The results are discussed from both theoretical and application points of view. Includes 37 references, tables, figures.