Two requirements of a porous filler for Mixed Matrix Membranes [MMMs] are a good adhesion to the polymer and the openness of its pores. The surface of SAPO-34 has been grafted with moieties containing amino groups, aromatic rings, and fluorinated chains, for a good adhesion to glassy polyimides, aromatic polymers and perfluoropolymers. The controlled excess of the modification agent â preferably trichlorosilanes â in hydrophobic solvents and the strict control of moisture in the reaction environment prevent the growth of thick layers of grafts around the crystals. XPS confirms the success of the derivatizations and indicates a homogeneous and thin coverage of the surface. The negligible reduction of the surface area suggests that the modification of the surface does not plug the micropores. The counter-intuitive faster adsorption of n-heptane in silicalite-1 after modification with bulky fluorinated grafts indicates the openness of the pores even for large molecules, and the reduction of the resistance to the transport of mass across the surface of the molecular sieves, thanks to the reduced amount of water adsorbed on the hydrophobic outer surface of the crystals.

Surface modification of molecular sieve fillers for mixed matrix membranes

Golemme, Giovanni
;
Policicchio, Alfonso;De Luca, Giuseppina;Russo, Beatrice;LIGUORI, PAOLA FRANCESCA;MELICCHIO, Alessandro;Agostino, Raffaele G.;DE LUCA, Giuseppina
2018-01-01

Abstract

Two requirements of a porous filler for Mixed Matrix Membranes [MMMs] are a good adhesion to the polymer and the openness of its pores. The surface of SAPO-34 has been grafted with moieties containing amino groups, aromatic rings, and fluorinated chains, for a good adhesion to glassy polyimides, aromatic polymers and perfluoropolymers. The controlled excess of the modification agent â preferably trichlorosilanes â in hydrophobic solvents and the strict control of moisture in the reaction environment prevent the growth of thick layers of grafts around the crystals. XPS confirms the success of the derivatizations and indicates a homogeneous and thin coverage of the surface. The negligible reduction of the surface area suggests that the modification of the surface does not plug the micropores. The counter-intuitive faster adsorption of n-heptane in silicalite-1 after modification with bulky fluorinated grafts indicates the openness of the pores even for large molecules, and the reduction of the resistance to the transport of mass across the surface of the molecular sieves, thanks to the reduced amount of water adsorbed on the hydrophobic outer surface of the crystals.
Mixed matrix membranes; Molecular sieve surface modification; n-Heptane adsorption kinetics; Surface barriers; Surface permeability; X-ray photoelectron spectroscopy; Surfaces and Interfaces; Physical and Theoretical Chemistry; Colloid and Surface Chemistry
File in questo prodotto:
File Dimensione Formato  
CollSurfA 2018 MS w Corr.pdf

solo utenti autorizzati

Descrizione: Manoscritto dopo revisione
Tipologia: Versione Editoriale (PDF)
Licenza: Copyright dell'editore
Dimensione 8.45 MB
Formato Adobe PDF
8.45 MB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11770/268943
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 11
  • ???jsp.display-item.citation.isi??? 10
social impact