Quantum sieve effects

The quantum sieving effects drop rapidly as the temperature increases, as shown in Figure 9.13. Using Eq. 9.3, Challa et al. (2001) calculated the selec-tivities for three different hydrogen isotope mixtures in the interstices of (10,10) SWNT bundles at different temperatures. The drop was due to the increased contribution from the excited states. Thirty energy states (in Eq. 9.3.) were used in their calculations. However, a selectivity of 5.2 for T2IH2 still remained at 77 K. 

It should be noted that the quantum sieving effects are not limited to the carbon nanotubes. Small-pore molecular sieves such as ALPO4-22 also could have such effects (Wang et al 1999). However, carbon nanotubes have the advantage of being the most smooth and uniform pores. The interesting quantum sieving effects remain to be proven experimentally. 

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