Page 270 - Adsorbents fundamentals and applications

PILLARED CLAYS 255

− − Clay layer
+ + + + Hydration
swelling
− −

− −
+ Pillar ion
+ H O + exchange
2
H O + H O
2
2
− −

− −
d 001 H O Dehydratation
p + 2 p +
H O
2
− −

P P

Figure 9.16. General scheme for synthesis of pillared clays (Butruille and Pinnavaia, 1996, with
permission).

most promising ones for use as adsorbents and catalysts are as follows: A1-PILC
(Vaughan et al., 1979, 1981a, b; Lahav et al., 1978; Shabtai et al., 1984a, b; Pin-
navaia et al., 1984; Occelli, 1984; Sterte, 1991; Suzuki et al., 1988; Occelli and
Tindwa, 1983; Pinnavaia, 1983; Burch, 1988; Figueras, 1988), Zr-PILC (Vaughan
et al., 1979,1981; Yamanaka and Brindley, 1979; Figueras et al., 1989; Burch
and Warburton, 1986; Bartley and Burch, 1986; Bartley, 1988; Yang and Baksh,
1991), Cr-PILC (Tzou and Pinnavaia, 1988; Carrado et al., 1986, Vaughan, 1987;
Shabria and Lahari, 1980; Pinnavaia et al., 1985), Fe-PILC (Yamanaka and Hat-
tori, 1988; Yamanaka et al., 1984; Burch and Warburton, 1987; Lee et al., 1989;
Pinnavaia and Tzou, 1987; Rightor et al., 1991), and Ti-PILC (Sterte, 1986).
The choices for hydroxy cations are not limited to those mentioned. In fact, any
metal oxide or salt that forms polynuclear species upon hydrolysis (Baes and
Mesmer, 1976) can be inserted as pillars, and all layered clays of the abun-
dant phyllosilicate family as well as other layered clays can be used as the