Solubility-normalized Dubinin-Astakhov adsorption isotherm for ion-exchange systems

Inglezakis, VJ

dc.contributor.author	Inglezakis, VJ	en
dc.date.accessioned	2014-03-01T01:27:16Z
dc.date.available	2014-03-01T01:27:16Z
dc.date.issued	2007	en
dc.identifier.issn	1387-1811	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/18371
dc.subject	Adsorption energy	en
dc.subject	Clinoptilolite	en
dc.subject	Dubinin-Astakhov isotherm	en
dc.subject	Dubinin-Radushkevich isotherm	en
dc.subject	Heterogeneity parameter	en
dc.subject	Ion exchange	en
dc.subject.classification	Chemistry, Applied	en
dc.subject.classification	Chemistry, Physical	en
dc.subject.classification	Nanoscience & Nanotechnology	en
dc.subject.classification	Materials Science, Multidisciplinary	en
dc.subject.other	Adsorption isotherms	en
dc.subject.other	Computation theory	en
dc.subject.other	Ion exchange	en
dc.subject.other	Lead	en
dc.subject.other	Positive ions	en
dc.subject.other	Adsorption energy	en
dc.subject.other	Clinoptilolite	en
dc.subject.other	Dubinin-Astakhov isotherm	en
dc.subject.other	Dubinin-Radushkevich isotherm	en
dc.subject.other	Heterogeneity parameter	en
dc.subject.other	Solubility	en
dc.subject.other	Adsorption isotherms	en
dc.subject.other	Computation theory	en
dc.subject.other	Ion exchange	en
dc.subject.other	Lead	en
dc.subject.other	Positive ions	en
dc.subject.other	Solubility	en
dc.title	Solubility-normalized Dubinin-Astakhov adsorption isotherm for ion-exchange systems	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/j.micromeso.2007.01.039	en
heal.identifier.secondary	http://dx.doi.org/10.1016/j.micromeso.2007.01.039	en
heal.language	English	en
heal.publicationDate	2007	en
heal.abstract	The well-known Dubinin-Radushkevich adsorption isotherm is extensively used for vapour adsorption on activated carbon and its use has been extended to cover the cases of the adsorption of organic compounds from aqueous solutions and the ion exchange of metals on several porous materials. In the later cases, the use of the Dubinin-Radushkevich adsorption isotherm is questionable as it is not taking into account the pore structure of the materials used. In the present paper the more general Dubinin-Astakhov adsorption isotherm is used modified by introducing a solubility-normalized adsorption potential. Then, it is applied in experimental isotherms in order to determine adsorption energy and heterogeneity parameter for the ion exchange of Pb2+ in the zeolite clinoptilolite. The results indicate that the Dubinin-Astakhov adsorption isotherm represents the experimental data well and in the same time provides the heterogeneity parameter of the material which is an important adsorbent physical parameter as well as the adsorption energy. The calculated values are found to be n = 5.2 and E congruent to 18 kJ/mol, respectively. An extended review is conducted by applying the proposed isotherm in experimental data found in the literature for clinoptilolite cation exchange systems (22 experimental isotherms, 175 equilibrium points). The average value of the heterogeneity parameter is n = 5.84 +/- 2.09 (35.8% deviation) with a range of 2.1-10.4. The results indicate that the heterogeneity parameter value is strongly influenced from the structure of the adsorbent and in lesser extend from the cation exchanged. The average value of the adsorption energy is E = 16.7 +/- 3.21 (19.2% deviation) with a range of 9.47-21.74 kJ/mol. (C) 2007 Elsevier Inc. All rights reserved.	en
heal.publisher	ELSEVIER SCIENCE BV	en
heal.journalName	Microporous and Mesoporous Materials	en
dc.identifier.doi	10.1016/j.micromeso.2007.01.039	en
dc.identifier.isi	ISI:000247482200010	en
dc.identifier.volume	103	en
dc.identifier.issue	1-3	en
dc.identifier.spage	72	en
dc.identifier.epage	81	en