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Adsorption by activated carbon is a promising technique to remove tracepharmaceuticals (PhACs) and endocrine disrupting substances (EDS), based on itscapability to remove pesticides in drinking water treatment. The objective of thisresearch is to determine the effectiveness of granular activated carbon (GAC), for theremoval of naproxen, carbamazepine, and nonlyphenol (NP) in the presence andabsence of background natural organic matter. The experimental results for naproxenare presented and discussed in this paper as an example.The capacities of two common GACs (coal-based F-400 from Calgon andcoconut-based TIF TE from PICA) were determined through isotherm tests on virgincarbon in ultrapure water and in post-sedimentation (PS) water from a full-scale planttreating river water. Competitive adsorption between naproxen and backgroundorganic matter in the PS water significantly decreased the adsorption capacity fornaproxen on both carbons compared to that in ultrapure water, albeit to differentdegrees. The characteristics (i.e. Freundlich parameters K and 1/n, and initialconcentration Co) of the equivalent background component (EBC), which representsall competing background compounds including natural organic matter (NOM), weredetermined and then used in conjunction with ideal adsorbed solution theory (IAST)to predict GAC capacities at different initial naproxen concentrations.Batch kinetic experiments showed that the preloading of NOM onto GACgreatly impacted both adsorption capacity and kinetics on F400 carbon. External masstransfer coefficients were determined by using short fixed bed (SFB) reactors, andalso estimated using the Gnielinski correlation. Experimentally determined externaldiffusion coefficients were larger than the ones estimated by the Gnielinski correlationon virgin F400 carbon, albeit approaching the latter with increasing preloading time.In future work, isotherm and kinetic data under competitive and preloading conditionswill be applied to a mass transfer model to predict the breakthrough of naproxen inGAC filters. Includes 29 references, tables, figures.

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Edition: Vol. - No. Published: 11/01/2006 Number of Pages: 11File Size: 1 file , 450 KB