Exceptional adsorptive capacity and kinetic of γ-Al2O3 for selective adsorption of NO assisted by nonthermal plasma

Adsorption equilibrium and kinetics of nitric oxide (NO) on candidate adsorbents under the irradiation of nonthermal plasma (NTP) were investigated by experimental research and prediction. The results showed that gamma-Al2O3 is a more promising candidate for NO adsorption compared with ZSM-5 and silicalite-2 in the presence of NTP and the breakthrough time. The adsorption capacity of gamma-Al2O3 showed significant increase with discharge power increasing from 0 to 7.5 W. The FTIR and TPD analysis suggested that NO was strongly adsorbed on the gamma-Al2O3 in the form of nitrate under the NTP. The breakthrough curves of NO adsorption on gamma-Al2O3 were also recorded at different initial conditions. Yoon-Nelson model was used to study the kinetic behavior of NO adsorption and correlated well with all breakthrough data under NTP. Equilibrium date was analyzed by Langmuir, Freundlich, and Sips models. The Langmuir model fitted significantly better than the other two models. The exceptional adsorptive capacity and kinetics of gamma-Al2O3 for NO adsorption under NTP can be attributed to the fact that NTP can promote the oxidation of NO to NO2 in the gas phase and the surface oxidative reaction of adsorbed species.