Transcript Ion Exchange of Zeolites in Polyethylene Oxide Oligomer Solutions Susan E. Latturner, Department of Chemistry, Florida State University, Tallahassee, FL 32306 Polyethylene oxide oligomers.

Ion Exchange of Zeolites in Polyethylene
Oxide Oligomer Solutions
Susan E. Latturner, Department of Chemistry,
Florida State University, Tallahassee, FL 32306
Polyethylene oxide oligomers are inexpensive polar liquids which
can be used as alternative solvents for ion exchange into porous
and layered oxides. Ion exchange of transition metal or rare earth
ions into zeolites using traditional aqueous exchange results in
structure degradation; this does not occur in PEO solutions.
2
X-ray diffraction data shows (a) the
decomposition of Zeolite X samples ionexchanged with Fe2+ in aqueous solution;
those exchanged in PEO solvents (b,c)
maintain their crystallinity and are more
catalytically active in deNOx reactions.
8000
Emission spectra of Er3+
exchanged Zeolite X samples;
those exchanged in aqueous
solution have a shifted Er
luminescence due to partial
degradation and incorporation
of Er3+ into framework sites.
Intensity
1.5
PEG-ME exchange
1
PEO-600 exchange
Aqueous exchange
0.5
No exchange
0
400
500
600
700
Wavelength (nm)
7000
6000
.
PEO oligomers enter the pores of zeolite
during ion exchange and are usually removed
during calcination. However, allowing them to
remain may promote CO2 adsorption by the
zeolite, or reduction of noble metal ions to
form nanoparticles in the cages.
Intensity
5000
4000
3000
c
2000
b
1000
a
0
10
15
20
25
30
35
2-Theta
40
45
50
55
(Ag nanoparticles in Zeolite X matrix, right)
800
900