3.4 Iodine desorption experiments
To examine the reusable possibility of shaped silicalite-1, the iodine
desorption experiments after iodine adsorption on shaped silicalite-1
were tested at 348 K,373 K and 398 K. The iodine desorption curves are
shown in Figure 11. The EDS spectrum and XRD pattern on shaped
silicalite-1 after iodine desorption are shown in Figure 12 and Figure
13 respectively. The results showed that the combination of adsorbent
and iodine was reversible, and followed a physical combination.
Moreover, the higher the temperature, the faster the desorption rate of
iodine. Iodine adsorbed under the saturated vapor pressure of iodine at
348 K could be desorbed completely after 6 hours proved by EDS spectrum
when the temperature increased at 398 K in Figure 12. Moreover, the
structure of shaped silicalite-1 had no change after iodine desorption,
manifesting the stability of adsorbent. It can be considered that the
shaped silicalite-1 all-silica zeolite could be recycled repeatedly and
continued to be used for iodine adsorption, providing the possibility
for iodine removal industrial applications.
Figure 11 Iodine desorption curves for silicalite-1 at different
temperatures
Figure 12 XRD patterns of silicalite-1