Pulsed field gradient NMR study of the diffusion of n-hexane confined in hydroxylated and dehydroxylated MCM-41 of various pore diameters

✍ Scribed by F Courivaud; E.W Hansen; A Karlsson; S Kolboe; M Stöcker

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 299 KB
• Volume: 35-36
• Category: Article
• ISSN: 1387-1811
• DOI: 10.1016/s1387-1811(99)00231-0

✦ Synopsis

The pore dimension of a reference MCM-41 material was reduced in a controlled manner by successive silylation with tetrachlorosilane. Also, the surface of these materials was modified by temperature treatment, resulting in a reduction of the concentration of surface silanol groups. Pulsed field gradient (PFG) NMR diffusion measurements of n-hexane confined in these modified MCM-41 samples have been performed and the results discussed within the Gaussian phase distribution and short gradient pulse approximations. The observed increase of the mean residence time with increasing diffusion time of the confined n-hexane suggests a distribution of channel lengths to exist.