Study of natural zeolites for hydrogen purification: CO2 adsorption capacity and kinetic mechanism
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Date
2024-11-15
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Fuel
Abstract
Hydrogen is considered a promising alternative fuel. However, in order to be used, it is necessary to achieve a high degree of purity through purification processes.
Adsorption is considered one of the most important techniques for purification. In this research, the CO2 adsorption capacity and kinetic mechanism of natural zeolite were investigated with the aim to understand the carbon dioxide adsorption behaviour under different operating conditions. Multicomponent breakthrough curves of a mixture of H2/CO/CH4/CO2 were obtained at different pressures and gas flow rates. Moreover, the analysis of CO2 adsorption equilibrium and kinetics were carried out. The obtained
adsorption isotherm data were fitted with different model equations. Freundlich, Sips and Toth models showed the best fit for the experimental data, indicating the heterogeneous nature of the adsorbent surfaces. The carbon dioxide adsorption kinetic was analysed using different kinetic models, obtaining that the adsorption process is both physical and chemical and that the limiting step of the diffusion process is intraparticle diffusion, although other processes are also involved such as diffusion through the boundary layer.
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Fuel Volume 376, 15 November 2024, 132732