(WO9620785-A1)      Adsorbent for separating N2 from a feed gas contg. at least one other gas having molecular dimensions equal to or larger than methane comprises clinoptilolite having a Na ion content of at least 17 equiv.% of the total ion exchangeable cations and opt. one or more non univalent cations, which if present comprise in total less than 12 equiv. % of the total ion-exchangeable cations, the balance if any being one or more non-Na univalent cations. Prodn. of the adsorbent is also claimed.    USE -   The adsorbent is used in cyclic adsorption processes, e.g. pressure swing and thermal swing adsorption separation e.g. for natural gas treatment.    ADVANTAGE -   Divalent exchangeable cations, e.g. Mg and Ca,can be minimised within the clinoptilolite to improve regeneration in a pressure swing adsorption process, while still maintaining or improving the rate selectively for N2 of the mineral.    (EP871541-A1)      Adsorbent for separating N2 from a feed gas contg. at least one other gas having molecular dimensions equal to or larger than methane comprises clinoptilolite having a Na ion content of at least 17 equiv.% of the total ion exchangeable cations and opt. one or more non univalent cations, which if present comprise in total less than 12 equiv. % of the total ion-exchangeable cations, the balance if any being one or more non-Na univalent cations. Prodn. of the adsorbent is also claimed.    USE -   The adsorbent is used in cyclic adsorption processes, e.g. pressure swing and thermal swing adsorption separation e.g. for natural gas treatment.    ADVANTAGE -   Divalent exchangeable cations, e.g. Mg and Ca,can be minimised within the clinoptilolite to improve regeneration in a pressure swing adsorption process, while still maintaining or improving the rate selectively for N2 of the mineral.    (GB2296712-B)      Adsorbent for separating N2 from a feed gas contg. at least one other gas having molecular dimensions equal to or larger than methane comprises clinoptilolite having a Na ion content of at least 17 equiv.% of the total ion exchangeable cations and opt. one or more non univalent cations, which if present comprise in total less than 12 equiv. % of the total ion-exchangeable cations, the balance if any being one or more non-Na univalent cations. Prodn. of the adsorbent is also claimed.    USE -   The adsorbent is used in cyclic adsorption processes, e.g. pressure swing and thermal swing adsorption separation e.g. for natural gas treatment.    ADVANTAGE -   Divalent exchangeable cations, e.g. Mg and Ca,can be minimised within the clinoptilolite to improve regeneration in a pressure swing adsorption process, while still maintaining or improving the rate selectively for N2 of the mineral.    (US5993516-A)      Adsorbent for separating N2 from a feed gas contg. at least one other gas having molecular dimensions equal to or larger than methane comprises clinoptilolite having a Na ion content of at least 17 equiv.% of the total ion exchangeable cations and opt. one or more non univalent cations, which if present comprise in total less than 12 equiv. % of the total ion-exchangeable cations, the balance if any being one or more non-Na univalent cations. Prodn. of the adsorbent is also claimed.    USE -   The adsorbent is used in cyclic adsorption processes, e.g. pressure swing and thermal swing adsorption separation e.g. for natural gas treatment.    ADVANTAGE -   Divalent exchangeable cations, e.g. Mg and Ca,can be minimised within the clinoptilolite to improve regeneration in a pressure swing adsorption process, while still maintaining or improving the rate selectively for N2 of the mineral.    (RU2145258-C1)      Adsorbent for separating N2 from a feed gas contg. at least one other gas having molecular dimensions equal to or larger than methane comprises clinoptilolite having a Na ion content of at least 17 equiv.% of the total ion exchangeable cations and opt. one or more non univalent cations, which if present comprise in total less than 12 equiv. % of the total ion-exchangeable cations, the balance if any being one or more non-Na univalent cations. Prodn. of the adsorbent is also claimed.    USE -   The adsorbent is used in cyclic adsorption processes, e.g. pressure swing and thermal swing adsorption separation e.g. for natural gas treatment.    ADVANTAGE -   Divalent exchangeable cations, e.g. Mg and Ca,can be minimised within the clinoptilolite to improve regeneration in a pressure swing adsorption process, while still maintaining or improving the rate selectively for N2 of the mineral.