Thermodynamics of nitrogen adsorption on the zeolite H-FER

摘要

Adsorption (at a low temperature) of nitrogen on the protonic zeolite H-FER results in hydrogen bonding of the adsorbed N_2 molecules with the zeolite Si(OH)Al Bronsted acid groups. This hydrogen bonding interaction leads to activation, in the IR, of the fundamental N-N stretching mode, which appears at 2331 cm~(-1). From the infrared spectra taken over a temperature range, while simultaneously recording integrated IR absorbance, temperature and nitrogen equilibrium pressure, the thermodynamics of the adsorption process was studied. The standard adsorption enthalpy and entropy resulted to be ΔH° = -20(±1) kJ mol~(-1) and ΔS° = -131(±10) J mol~(-1) K~(-1), respectively.