Page 559 - Fundamentals of Water Treatment Unit Processes : Physical, Chemical, and Biological

514 Fundamentals of Water Treatment Unit Processes: Physical, Chemical, and Biological

x
y
z
(a) (b)

y
z
x
x y
z
(c) (d)

FIGURE 16.1 Examples of zeolites illustrating different Framework Types with codes in parenthesis. (a) Linde Type A (LTA)–synthetic;
(b) Faujasite (FAU)–mineral; (c) Chabazite (CHA)–mineral; (d) Clinoptilolite (HEU)–mineral. (From Baerlocher, Ch. and McCusker, L. B.,
Database of zeolite structures, http:==www.iza-structure.org=databases, June 2003. With permission from International Zeolite Association.)

ABW has some 22 ‘‘materials,’’ e.g., [Be-As-O]-ABW;
[Be-As-O]-ABW; [Be-P-O]-ABW; [Ga-Si-O]-ABW; . . . , TABLE 16.2
jNaj[Zn-P-O]-ABW (Baerlocher et al., 2007, p. 14; IZA, Examples of Zeolite Materials and Respective IZA
2010). The convention is that the vertical bold bars encom- Framework Type Codes
pass the ‘‘guest’’ species and the brackets encompass the a
Mineral Synthetic
‘‘host’’ species (McCusker et al., 2001, p. 388).
b
b
Sodalite =SOD ZSM-5 =MFI
Examples: Figure 16.1 illustrates four of the 194 zeolite Clinoptilolite (Heulandite)=HEU UZM-4 =MAZ
c
Framework Types. The first, Linde Type A, under the Chabazite=CHA UZM-5 =UFI
b
‘‘LTA’’ Framework Type is synthetic. The others, i.e., Fauja- Analcime=ANA Linde Type A =LTA
a
d
site-FAU, Chabazite-CHA, Clinoptilolite-HEU, are minerals, Faujasite =FAU e Linde Type X =FAU e
b,d
i.e., found in nature. Table 16.2 lists some of the zeolites Linde Type Y =FAU e
b,d
mentioned in the literature and further illustrates the IZA
classification system; see for example, footnotes ‘‘d’’ and Source: Adapted from Helfferich, F., Ion-Exchange, McGraw-Hill,
New York, p. 29, 47, 1962.
‘‘e’’ that pertain to FAU. As illustrated, Linde Type X and
a Helfferich, 1962, p. 10;
Linde Type Y (both synthetic zeolites) and Faujasite (a min- b Kerr, 1989, pp. 102, 104;
eral zeolite), have the FAU Framework Type. c
Jacoby, 2003, p. 38;
d Faujasite is a rare zeolite mineral. The synthetic versions, used
IZA classification system: To further explicate in terms of the
commercially, are known as Linde Type X, and Linde Type Y,
IZA system, a zeolite Framework Type, e.g., ‘‘FAU’’ (IZA,
2010), Figure 16.1 and Table 16.1, respectively, describes respectively; they differ in their Si=Al ratios, i.e., for Linde Type X: (1.0
Si=Al 1.5); and for Linde Type Y: (1.5 Si=Al 3.0).
only the ‘‘connectivity’’ of the framework, while a zeolite e
A number of zeolites have the FAU Framework Type, including Faujasite,
structure is that of a specific material, i.e., for a given frame- Linde Type X, Linde Type Y, and about 20 others. Others not listed in
work there are often many zeolite structures. The hierarchy Table 16.1.
within the IZA web-site is: IZA (2010)=Zeolite Framework