Evaluating GAC adsorptive capacity

Potential sources of error in evaluating the adsorptive capacity of granular activated carbon (GAC) are identified and discussed, with special attention given to carbon sampling and preparation, preparation of test solutions, and selection of GAC dosages, adsorbate concentration, and equilibration time. Adsorptive capacity can vary with particle size, but data are presented to show that this may not always occur. Heterogeneous solutions require careful selection of GAC dosages and adsorbate concentration, and the data for such solutions require careful interpretation. Model simulations are used to illustrate the importance of closely approaching equilibrium and to estimate the time required to approach equilibrium under various conditions. For large GAC particles and slowly diffusing adsorbates, several years may be required to reach equilibrium. Failure to reach equilibrium can result in a significant underestimation of adsorptive capacity. Pulverizing GAC greatly reduces the time required to reach equilibrium, thus reducing the possibility of biodegradation of the adsorbate.

[1]  W. E. Ranz,et al.  Evaporation from drops , 1952 .

[2]  Vernon L. Snoeyink,et al.  Humic substances removal by activated carbon , 1980 .

[3]  Walter J. Weber,et al.  Equilibria and Capacities for Adsorption on Carbon , 1964 .

[4]  C. Wilke,et al.  Correlation of diffusion coefficients in dilute solutions , 1955 .

[5]  Removing nonvolatile organic chlorine and its precursors by coagulation and softening , 1983 .

[6]  V. Snoeyink,et al.  Organic compounds produced by the aqueous free-chlorine-activated carbon reaction. , 1981, Environmental science & technology.

[7]  R. Coughlin,et al.  Role of surface acidity in the adsorption of organic pollutants on the surface of carbon , 1968 .

[8]  G. V. Calder,et al.  Use of macroreticular resins in the analysis of water for trace organic contaminants. , 1974, Journal of chromatography.

[9]  J. Kipling,et al.  Adsorption from binary liquid mixtures: some effects of ash in commercial charcoal , 1955 .

[10]  S. Randtke,et al.  Effects of salts on activated carbon adsorption of fulvic acids , 1982 .

[11]  R. G. Peel,et al.  Attainment of equilibrium in activated carbon isotherm studies , 1980 .

[12]  P. Harriott.  Mass transfer to particles: Part I. Suspended in agitated tanks , 1962 .

[13]  J. R. Glastonbury,et al.  Application of Kolmogorofff's theory to particle—liquid mass transfer in agitated vessels , 1972 .

[14]  R. Prober,et al.  Interaction of activated carbon with dissolved oxygen , 1975 .

[15]  W. Weber,et al.  The surface chemistry of active carbon; a discussion of structure and surface functional groups , 1967 .

[16]  R. Martin,et al.  Adsorption studies using gas-liquid chromatography—III. Experimental factors influencing adsorption , 1978 .

[17]  Stephen J. Randtke,et al.  Formation of organic chlorine in public water supplies , 1983 .

[18]  R. Eilers,et al.  Treatment of drinking water containing trichloroethylene and related industrial solvents , 1982 .

[19]  Stephen J. Randtke,et al.  Removing soluble organic contaminants by lime‐softening , 1982 .

[20]  S. Randtke,et al.  Chemical pretreatment for activated‐carbon adsorption , 1981 .

[21]  Randolph R. Munch,et al.  Correction for total organic carbon, nitrate, and chemical oxygen demand when using the MF-millipore filter , 1979 .

[22]  V. Snoeyink,et al.  Competitive adsorption of 2,4-dichlorophenol and 2,4,6-trichlorophenol in the nanomolar to micromolar concentration range , 1979 .

[23]  Vernon L. Snoeyink,et al.  Activated carbon adsorption of humic substances , 1981 .