Adsorption Behavior Of Toluene On Modified 13X Molecular Sieve

Molecular sieves with crystalline aluminosilicate frameworks are another type adsorbent and attracting considerable attention recently.They have a large amount of adsorption capacity,specific surface area and excellent fire resistance which are used in VOCs treatment widely.However,most of them should be modified due to low hydrophobicity.In this paper,used air as carrier gas,modified 13X molecular sieve(M-13X)was investigated and compared with commercialized 13X which had great significant in technology of VOCs abatement.The relative crystallinity of M-13X which was higher than 13X and USY molecular sieves was 32.12,which demonstrated M-13X had well organized crystalline structure and uniform channels.The SEM measurements illustrated that many channels were exist and arranged regularly in M-13X.BET measurement indicated the specific surface area,average pore diameter and pore volume of M-13X were 414.17 m2/g,2.98 nm and 0.31 mL/g,respectively,which were quite close with 13X.Due to the larger Si/Al ratio of M-13X(Si/Al=6.77),M-13X had a much higher hydrophobicity than 13X zeolite(Si/Al=1.28).For the simulated toluene-containing stream,the saturated adsorption capacity of M-13X was 0.045 g/g at the temperature of 293K and the relative humidity of 50%.The influence of gas flow rate was researched,which indicated that 24m/min was the suitable flow rate.The M-13X also had high hydrophobicity which was particularly well suited for toluene control applications could meet the needs of VOCs control under actual working conditions according to water isotherms and breakthrough curves under wet condition.The optimal regeneration temperature of M-13X was 473K for 2 h with a hot air flow velocity of 200 m/min.The results of present investigation can directly provide a practical guide for design.