A study of the thermal regeneration of carbon and zeolite adsorbents after adsorption of 1-hexene vapor

[Display omitted] •Zeolite adsorbs less 1-hexene (1.2 mol/kg) than activated carbons (up to 4 mol/kg)•The isosteric heats in the adsorption systems indicate physisorption (51–63 kJ/mol)•Nearly irreversible isotherms predestine the thermal method of adsorbent regeneration.•Thermal regeneration of the used adsorbents at 120–150 °C enables recovery of 1-hexene.•NIR spectroscopy as a tool for investigation of adsorption and thermal regeneration. The adsorption isotherms of 1-hexene (HEX) vapor on BPL and Sorbonorit activated carbons (AC), and HiSiv3000 (HS) zeolite exhibit an almost rectangular shape, which favors the application of the thermal method to regenerate the loaded adsorbent. The minimum desorption energy was estimated in the range of 51–63 kJ/mol. The thermal stability and the possibility of adsorbed particles detection in loaded adsorbents were studied using TGA, XRD and NIR/DRS methods. The maximum temperatures on the DTG desorption curves of 120 °C for HS and 150 °C for AC correspond to the optimal desorption temperatures. These temperatures ensure the safe regeneration of the adsorbent in the air and the recovery of the HEX unchanged. The regeneration degree of the loaded HS calculated with an alternative method based on isotherms on fresh and regenerated adsorbent reaches 75 %, which is in line with the observed changes on NIR/DRS spectra. The obtained results revealed the potential of the still underestimated NIR/DRS spectroscopic method in non-destructive testing of adsorbents in their original shape and size, the possibility of confirming the chemical identity of adsorbed particles, assessing the hydrophobicity of the adsorbent and investigating the mechanism of the adsorbent-adsorbate interaction during the adsorption and thermal regeneration processes.