Adsorption environments, TSLS complex

Adsorption environments, TSLS complex, 120,12 Adsorption measurements, procedures, 90 Adsorption sites, distinguishing between, 93-94 Aging, effect on particle size of titanium dioxide sols, 200-201,203/... 

The microporosity of a new tubular silicatelayered silicate nanocomposite formed by the intercalation of imogolite in Na -montmorillonite has been characterized by nitrogen and m-xylene adsorption. The nitrogen adsorption data yielded liquid micropore volume of -0.20 cm g as determined by both the t-plot and the Dubinin-Radusikevich methods. The t-plot provided evidence for a bimodal pore structure which we attributed to intratube and intertube adsorption environments. The m-xylene adsorption data indicated a much smaller liquid pore volume (-0.11 cm g ), most likely due to incomplete filling of intratubular pores by the planar adsorbate. The FTIR spectrum of pyridine adsorbed on the TSLS complex established the presence of both Bronsted and Lewis acid sites. The TSLS complex was shown to be active for the acid-catalyzed dealkylation of cumene at 350 C, but the complex was less reactive than a conventional alumina pillared montmorillonite. 

A schematic representation of a TSLS complex is provided in Figure 1. On the basis of preliminary XRD and stochiometric studies, it appears that the imogolite tubes are in van der Waals contact, most likely in a log-jam-like array in the layer silicate galleries. Although the tubes stuff the galleries, two unique adsorption environments are available, namely, the intra-and inter-tube pores designated A and B in Figure 1. 

---