Desorption rate curves of n-pentane on 5A zeolites at 418K and 10-0.03kPa were determined, and the effects of different macropore structure on desorption performance were analyzed. Results showed that macropore distribution of 5A-1 concentrated in 0.25-1.25μm, while that of 5A-2 ranged from mesopore category to 0.3μm, but 5A-3 contained both pores of 0.01-0.1μm and 0.2-2μm, reflecting the broadest distribution; 5A-3, 5A-1 and 5A-2 reached desorption equilibrium after 1100, 1400 and 2000s respectively at 0.03kPa, indicating that abundant macropores made n-pentane fastest to desorb from 5A-3, but this advantage gradually disappeared with increasing pressure; the effective desorption diffusion coefficients of n-pentane on 5A-1, 5A-2 and 5A-3 were 4.2 x 10-15 to 2.2 x 10-14, 2.0 x 10-15 to 2.3 x 10-14, 7.4 x 10-15 to 2.4 x 10-14m2/s, respectively, suggesting that plentiful macropores rendered diffusivity less affected by changes in pressure, which could guarantee a fast diffusion rate of n-pentane even at low pressure.

Effect of Macropore Structure on Desorption Diffusion Performance of n-Pentane on 5A Zeolite. L.Shi, Z.Liu, Q.Cui, H.Wang, H.Yao: Advanced Materials Research, 2013, 634-638[1], 731-5