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Conflict of Interest: In relation to this article, we declare that there is no conflict of interest.

Publication history: Received June 9, 2005
Accepted December 23, 2005

This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/bync/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

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Effect of backwashing on activated carbon adsorption using plug flow pore surface diffusion model

Seongho Hong^† R. Scott Summers¹

Department of Chemical & Environmental Engineering, Soongsil University, Seoul 156-743, Korea ¹Dept. of Civil, Environmental and Architectural Engineering, University of Colorado, Boulder, CO 80309-0428, USA

shong@ssu.ac.kr

Korean Journal of Chemical Engineering, January 2006, 23(1), 57-62(6), 10.1007/BF02705692

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Abstract

A fixed bed is gradually exhausted from top to bottom without backwashing; however, backwashing can rearrange the concentration gradient in the bed. After backwashing, saturated particles which are located at the top of the bed are homogeneously distributed in the bed. The used model to predict adsorption and backwashing effect of organic component is the plug flow pore surface diffusion model (PFPSDM). A sensitivity analysis was performed to determine which parameters have the greatest impact on the model results for components which can represent various organics. In addition, the effects of backwashing were examined by rearranging concentration gradient. For single component sensitivity analysis, the molecular weight was an important parameter. The breakthrough of the smaller molecular weight component was impacted more by backwashing. The SPDFR showed a significant impact on the breakthrough pattern. When surface diffusion was the dominant mechanism, high SPDFR, the breakthrough profile was sharper than when pore diffusion was dominant, low SPDFR. The adsorbability was an important parameter in determining the breakthrough pattern. As expected, the strongly adsorbable component showed the later breakthrough. Backwashing yielded earlier breakthrough for all single components and multi-components examined.

Keywords

GAC Adsorption Backwashing NOM Freundlich Isotherm

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