The effect of surface functionalization of mesoporous silicas with propylimidazol on porosity, pore connectivity and tortuosity

Armatas, GS; Salmas, CE; Androutsopoulos, GP; Pomonis, PJ

dc.contributor.author	Armatas, GS	en
dc.contributor.author	Salmas, CE	en
dc.contributor.author	Androutsopoulos, GP	en
dc.contributor.author	Pomonis, PJ	en
dc.date.accessioned	2014-03-01T02:42:10Z
dc.date.available	2014-03-01T02:42:10Z
dc.date.issued	2002	en
dc.identifier.issn	0167-2991	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/30832
dc.subject	Pore Size Distribution	en
dc.subject	Pore Structure	en
dc.subject	Silica	en
dc.subject	Specific Surface Area	en
dc.subject	Full Width at Half Maximum	en
dc.subject.classification	Chemistry, Physical	en
dc.subject.other	imidazole	en
dc.subject.other	silicon dioxide	en
dc.subject.other	acidity	en
dc.subject.other	analytic method	en
dc.subject.other	calculation	en
dc.subject.other	conference paper	en
dc.subject.other	intermethod comparison	en
dc.subject.other	measurement	en
dc.subject.other	particle size	en
dc.subject.other	porosity	en
dc.subject.other	reaction analysis	en
dc.subject.other	simulation	en
dc.subject.other	solid	en
dc.subject.other	surface property	en
dc.title	The effect of surface functionalization of mesoporous silicas with propylimidazol on porosity, pore connectivity and tortuosity	en
heal.type	conferenceItem	en
heal.identifier.primary	10.1016/S0167-2991(02)80148-3	en
heal.identifier.secondary	http://dx.doi.org/10.1016/S0167-2991(02)80148-3	en
heal.language	English	en
heal.publicationDate	2002	en
heal.abstract	Mesoporous silica was gradually functionalized with silano-(trimethoxy)-propylimidazole (STPI) groups. The degree of surface functionalization n=0, 0.23, 0.30, 0.40, 0.52, 0.60 and 0.85 was controlled by previous knowledge of surface acidity, determined by TPD/NH3. From N-2 adsorption/desorption measurements the specific surface area S-p (m(2) g(-1)), the specific pore volume V-p (cm(3) g(-1)) and the corresponding pore size distributions PSD were determined while the connectivity c of the solids was calculated according to the method of Seaton. The increase of functionalization resulted in a linear drop of S-p and V-p while the maximum D-max of the PSD and the Full Width at Half Maximum, FWHMsimilar to2sigma of distribution drop in a regular way whereas the ratio (D-max/2sigma) remains practically constant. The connectivity c also decreases from c=12.5 at n=0 to c=3 at n=0.60-0.85 presumably because of blocking of channels connecting various pores. Next, the co-called Corrugated Pore Structure Model, CPSW, was employed for the estimation of tortuosity tau of the porous solids and the simulation of the experimental adsorption/desorption isotherms. From those CPSM simulations the corresponding specific surface areas S-cpsm (m(2)g(-1)), specific pore volume V-cpsm (cm(3) g(-1)) and the corresponding pore size distribution PSDcpsm were estimated. The tortuosity tau of the system drops with the degree of functionalization from tau=4.22 at n=0 to tau=3.37 at functionalization n=0.23 while subsequently remains practically constant at about tau=3.40+/-0.10, for the same reasons which affect the connectivity i.e. blocking of various pore channels. The comparison between the parameters V-p on one hand and V-cpsm, is quite satisfactory while the S-cpsm values appear systematically higher by almost 8-23% compared to the S-p ones. Similarities and discrepancies between the results obtained by the two methods are discussed.	en
heal.publisher	ELSEVIER SCIENCE BV	en
heal.journalName	Studies in Surface Science and Catalysis	en
heal.bookName	STUDIES IN SURFACE SCIENCE AND CATALYSIS	en
dc.identifier.doi	10.1016/S0167-2991(02)80148-3	en
dc.identifier.isi	ISI:000180452700039	en
dc.identifier.volume	144	en
dc.identifier.spage	299	en
dc.identifier.epage	306	en