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This study compares uptake of post-filtration total organic carbon (TOC) (obtained from the Cincinnati Water Works) by virgin and thermally reactivated activated carbons with uptake by their surface modified counterpart activated carbons. One reactivated granular activated carbon (GAC) had experienced five cycles of treatment and reactivation (5xReac), whereas the other had experienced twelve cycles (12xReac). The virgin and reactivated carbons were surface modified by treating at 1000C for 3 hours in nitrogen followed by 1 hour in hydrogen, and these "Surface-Modified" carbons contained much less surface acidic functionality and a higher net positive charge than their "As-Received" counterpart carbons. Adsorption experiments were conducted at pH 3 and 7.9. The results of this study demonstrate that TOC uptake by the Cincinnati carbons was impeded by the presence of surface acidic functionality, and simultaneously enhanced by the presence of a net positive charge. Moreover, the prominence of these acidic/basic sites were most influential at low surface coverage conditions where the electrostatic interactions of natural organic matter (NOM) anions with surface acidic and basic sites on the carbon surface would have been the main electrostatic components to influence NOM uptake. Includes 36 references, table, figures.

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Edition: Vol. - No. Published: 11/01/2002 Number of Pages: 22File Size: 1 file , 460 KB