Before adsorption experiments, the adsorbent was pretreated
with helium at 300 C for 1 h with an electric furnace (these conditions
can remove up to 98% of the water in zeolites) 0.1 g of the
adsorbent was used for each experiment. When the concentration
of VOCs in a stream was stable, adsorption was started by passing
the stream over the adsorbent bed. After adsorbent bed saturation,
the stream containing VOC vapor was changed to pure helium flow
by using a six-way valve. Then, reversibly adsorbed VOC vapor was
sufficiently desorbed and purged with helium at 25 C for 1 h before
beginning the desorption experiments. Desorption experiments
were started once the TCD signal was stable. The
components in the effluent gas desorbed by microwave heating
were partly analyzed using on-line GC equipped with Porapak Q
column (1/8 in., 6 ft, Stainless steel).