1-Hexene adsorption performance
1-Hexene gas phase adsorption was carried out to determine the
adsorption capacity of the as-synthesized binderless zeolite X pellets.
Several commercial binder-containing products were also tested as
references (see Figure 7a). The 1-hexene adsorption capacity of
synthesized binderless zeolite X sample is 20-35% higher than those of
the four commercial binder-containing products, labeled as zeolite X-I
– X-IV. Specifically, the adsorption capacities are 178.2 mg/g for the
binderless zeolite X pellets, 133.6 mg/g for zeolite X-I, 117.9 mg/g for
zeolite X-II, 141.2 mg/g for zeolite X-III, and 137.5 mg/g for zeolite
X-IV. Compared with the final product synthesized attc = 24 h (see Figure 4), the SEM images shown in
Figure 7b reveal that the zeolite crystals of all binder-containing
samples are covered with large amount of binder which has significantly
negative impact in the adsorption performance, both capability and rate.
Additionally, according the pore structure analysis results listed in
Table S3, all binder-containing samples present smaller BET specific
surface areas and total pore volumes compared with binderless zeolite X
synthesized here. This can be ascribed to the dilution effect as well as
filling of space among zeolite crystals and added binder
species.35 Therefore, the binderless zeolite X we
synthesized is a promising candidate for adsorption of olefin compounds
with significantly enhanced capacity and affinity.