Kinetics and equilibrium of dissolved oxygen adsorption on activated carbon

Matsis, VM; Grigoropoulou, HP

dc.contributor.author	Matsis, VM	en
dc.contributor.author	Grigoropoulou, HP	en
dc.date.accessioned	2014-03-01T01:28:43Z
dc.date.available	2014-03-01T01:28:43Z
dc.date.issued	2008	en
dc.identifier.issn	0009-2509	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/18936
dc.subject	Activated carbon	en
dc.subject	Adsorption isotherm	en
dc.subject	Dissolved oxygen	en
dc.subject	Kinetics	en
dc.subject	Mass transfer	en
dc.subject	Porous media	en
dc.subject.classification	Engineering, Chemical	en
dc.subject.other	Activated carbon	en
dc.subject.other	Adsorption isotherms	en
dc.subject.other	Mass transfer	en
dc.subject.other	Porous materials	en
dc.subject.other	Reaction kinetics	en
dc.subject.other	Oxygen concentrations	en
dc.subject.other	Potentiometric titrations	en
dc.subject.other	Dissolved oxygen	en
dc.subject.other	Activated carbon	en
dc.subject.other	Adsorption isotherms	en
dc.subject.other	Dissolved oxygen	en
dc.subject.other	Mass transfer	en
dc.subject.other	Porous materials	en
dc.subject.other	Reaction kinetics	en
dc.title	Kinetics and equilibrium of dissolved oxygen adsorption on activated carbon	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/j.ces.2007.10.005	en
heal.identifier.secondary	http://dx.doi.org/10.1016/j.ces.2007.10.005	en
heal.language	English	en
heal.publicationDate	2008	en
heal.abstract	The macroscopic adsorption behavior of dissolved oxygen on a coconut shell-derived granular activated carbon has been studied in batch mode at 301 and 313 K for initial dissolved oxygen concentrations of 10-30 mg/l and oxygen/carbon ratios of 2-180 mg/g. BET (Brunauer, Emmett, and Teller) surface area, micropore volume, and pore size distribution were determined from N2 isotherm data for fresh and used samples of carbon. The surface groups were characterized using Boehm titrations, potentiometric titrations, and FTIR study. The material is characterized by its high specific surface area (1307 m2 / g), microporocity (micropore volume 0.54 cm3 / g), its basic character (0.57 meq / g total basic groups) and its high iron content (15,480 ppm Fe). BET n-layer isotherm describes adsorption equilibrium suggesting cooperative adsorption and important adsorbate-adsorbate interactions. Kinetic data suggest a process dependent on surface coverage. At low coverage a Fickian, intraparticle diffusion rate model assuming a local equilibrium isotherm (oxygen dissociation reaction) adequately describes the process. The calculated diffusion coefficients (D) vary between (4.7 - 8.2) × 10- 9 m2 / min and (3.5 - 5.3) × 10- 9 m2 / min for initial oxygen concentration of 10 and 20 mg/l, respectively. Sensitivity analysis shows that the oxygen dissociation equilibrium constant determines the equilibrium concentration, whereas the diffusion coefficient controls the kinetic rate of the adsorption process having no effect at the final equilibrium concentration. A combined kinetic mass transfer model with concentration-dependent diffusion (parabolic form) has been developed and successfully applied on the dissolved oxygen adsorption system at high surface coverage. For equilibrium uptake of 0.08 mg / m2 the estimated mean mass transfer coefficient and adsorption rate constant are 3.38 × 10- 5 m / min and 1.0 × 10- 2 l / (m2 min), respectively. © 2007 Elsevier Ltd. All rights reserved.	en
heal.publisher	PERGAMON-ELSEVIER SCIENCE LTD	en
heal.journalName	Chemical Engineering Science	en
dc.identifier.doi	10.1016/j.ces.2007.10.005	en
dc.identifier.isi	ISI:000253027700006	en
dc.identifier.volume	63	en
dc.identifier.issue	3	en
dc.identifier.spage	609	en
dc.identifier.epage	621	en