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Titolo:
Acidic porous clay heterostructures: study of their cation exchange capacity
Autore:
Benjelloun, M; Cool, P; Linssen, T; Vansant, EF;
Indirizzi:
Univ Instelling Antwerp, Dept Chem, Lab Adsorpt & Catalysis, B-2610 Wilrijk, Belgium Univ Instelling Antwerp Wilrijk Belgium B-2610 , B-2610 Wilrijk, Belgium
Titolo Testata:
MICROPOROUS AND MESOPOROUS MATERIALS
fascicolo: 1-3, volume: 49, anno: 2001,
pagine: 83 - 94
SICI:
1387-1811(20011115)49:1-3<83:APCHSO>2.0.ZU;2-V
Fonte:
ISI
Lingua:
ENG
Soggetto:
MESOPOROUS MOLECULAR-SIEVES; ALUMINA-PILLARED MONTMORILLONITE; CATALYSTS; ION;
Keywords:
porous clay heterostructure; combined micro- and mesoporosity; cation exchange capacity; extraction; ammonia adsorption;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
25
Recensione:
Indirizzi per estratti:
Indirizzo: Benjelloun, M Univ Instelling Antwerp, Dept Chem, Lab Adsorpt & Catalysis,Univ Plein 1,B-2610 Wilrijk, Belgium Univ Instelling Antwerp Univ Plein 1 Wilrijk Belgium B-2610
Citazione:
M. Benjelloun et al., "Acidic porous clay heterostructures: study of their cation exchange capacity", MICROP M M, 49(1-3), 2001, pp. 83-94

Abstract

The cation exchange capacities (CECs) of two porous clay heterostructures (PCHs), derived from natural montmorillonite (PMH) and synthetic saponite (PSH), have been studied. Both materials are highly porous, with surface areas of 997 m(2)/g (PMH) and 1118 m(2)/g (PSH). In order to obtain exchangeable ammonium cations in the pore structures of the PCHs, different modifications are performed on calcined and extracted PMH and PSH. Three methods forthe formation of NH4+-exchanged PCH forms are described and evaluated: (1)adsorption of ammonia under a gas flow on calcined and extracted PCHs in acidified methanol; (2) direct exchange in NH4Cl solution; (3) solvent extraction with NH4Ac/EtOH/H2O. The obtained ammonium containing materials are subsequently exchanged for KI cations in aqueous solution in order to determine the CEC of the PCH solids. With Kj-N analysis and infrared-DRIFT technique, evidence is found for the presence of ammonium cations on the surface of PCHs. The stability (crystallinity and porosity) of the porous solids under the different treatments has been investigated using X-ray diffraction and N-2-adsorption isotherms. The adsorption under NH3 gas flow proves to be the best method for maintaining the porosity of the studied PCHs. MaximalK+ loadings of 0.55 mmol/g (PMH) and 0.37 mmol/g (PSH) are obtained for ammonia-loaded and extracted PCH samples in MeOH/HCl. (C) 2001 Elsevier Science B.V. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 14/07/20 alle ore 06:37:40