Characterization of Co, Fe and Mn-exchanged zeolites by inverse gas chromatography.

The adsorption of several alkanes, cyclic hydrocarbons, aromatic hydrocarbons and chlorinated compounds on NaX, CaA, and exchanged Co, Mn and Fe zeolites as adsorbents was investigated. Zeolite composition and structure was determined by ICP-mass spectroscopy, XRD, and nitrogen adsorption. Adsorption parameters (enthalpy of adsorption and free energy of adsorption) as well as dispersive surface energy interaction and specific interaction parameters were determined for each solute-adsorbent system by inverse gas chromatography (IGC). The original zeolites NaX and CaA show the higher values of enthalpy of adsorption but specific interactions depend on the metal exchanged. Zeolites Mn-NaX and Co-NaX exhibit the strongest interactions with benzene, whereas zeolite Co-CaA shows the strongest interactions with chlorinated compounds. The trivalent cation (Fe3+) does not affect the either the adsorption efficiency or specific interaction.