[The study of adsorption properties of SAPO-34 molecular sieve by in situ DRIFTS].
The adsorption of H2O, NH3 and NO in molecular sieve SAPO-34 was studied by in situ DRIFTS at temperatures from 298 K to 773 K. The results show that the phenomenon of adsorption is reversible for H2O, but not for NH3 and NO. The water in SAPO 34 is absolutely deadsorbed at 623 K and the bridged Si-OH-Al group is observed at 3,625-3,600 cm-1. It is found that SAPO-34 displays good adsorption-catalysis activity for NH3 and NO. After adsorbing NH3, the bridged hydroxyls disappear, but three peaks appear at 3,135, 3,032 and 1,399 cm-1 at 423 K, and reach their climax at 673 K. The height of the peaks are 3.9, 1.7 and 6.7 times as much as SAPO-34 framework peak's, respectively. A strong and sharp peak is also observed at 1,364 cm-1 after NO adsorption at room temperature, and it exhibit approximately the same intensity with the framework peak. Analysis of these peaks indicate that there could produce new species NO3-.
Zhang
Ping
P
Department of Chemical Engineering, South China University of Technology, Department of Environmental Science, Guangzhou University, Guangzhou, China.
Wang
Le-fu
LF
Li
Xue-hui
XH
D000327:Adsorption; D000538:Aluminum Silicates / Q000737:chemistry*; D000641:Ammonia / Q000737:chemistry; D017665:Hydroxyl Radical / Q000737:chemistry; D009569:Nitric Oxide / Q000737:chemistry; D010710:Phosphates / Q000737:chemistry*; D012542:Scattering, Radiation; D013055:Spectrophotometry, Infrared / Q000379:methods; D013499:Surface Properties; D013696:Temperature
D000538:Aluminum Silicates; D010710:Phosphates; D009569:Nitric Oxide; D017665:Hydroxyl Radical; D000641:Ammonia