GB2296712-A  D M Ruthven, ADSORPTION AND ADSORPTION PROCESSES, Academic Press, 1984;  D W Breck, ZEOLITE MOLECULAR SIEVES, John Wiley and Sons, 1974;  D W Breck, ZEOLITE MOLECULAR SIEVES, John Wiley and Sons, 1974, p636;  R T Yang, GAS SEPARATION BY ADSORPTION PROCESSES, Butterworths, 1987;  T C Frankiewicz and R G Donelly (Chapter 11, INDUSTRIAL GAS SEPARATIONS, American Chemical Society, 1983WO9620785-A1  DATABASE WPI Week 8833 Derwent Publications Ltd., London, GB; AN 88-230367 & JP,A,63 162 519 (TPYO SODA) , 6 July 1988;  DATABASE WPI Week 8833 Derwent Publications Ltd., London, GB; AN 88-230367 & JP,A,63 162 519 (TPYO SODA), 06/07/1988;  IND. AND ENG. CHEM. RES., vol. 30, no. 12, 1991 WASHINGTON, pages 2523-2530, XP 000274307 M.W. ACKLEY 'ADSORPTION CHARACTERISTICS OF HIGH-EXCHANGE CLINOPTILOLITES';  IND. AND ENG. CHEM. RES., vol. 30, no. 12, 1991 WASHINGTON, pages 2523-2530, XP 000274307 M.W. ACKLEY "ADSORPTION CHARACTERISTICS OF HIGH-EXCHANGE CLINOPTILOLITES";  PATENT ABSTRACTS OF JAPAN vol. 11 no. 361 (C-459) & JP,A,62 132727 (TOYO SODA) 16 June 1987,;  PATENT ABSTRACTS OF JAPAN vol. 11 no. 361 (C-459) & JP,A,62 132727 (TOYO SODA) 16/06/1987;  ZEOLITES, vol. 12, September 1992 pages 780-788, XP 000567633 M.W.ACKLEY 'CLINOPTILOLITE: UNTAPPED POTENTIAL FOR KINETIC GAS SEPARATIONS';  ZEOLITES, vol. 12, September 1992 pages 780-788, XP 000567633 M.W.ACKLEY "CLINOPTILOLITE: UNTAPPED POTENTIAL FOR KINETIC GAS SEPARATIONS";  See also references of EP 0871541A1;  DATABASE WPI Week 8833 Derwent Publications Ltd., London, GB; AN 88-230367&JP,A,63 162 519 (TPYO SODA) , 6 July 1988;  PATENT ABSTRACTS OF JAPAN vol. 11 no. 361 (C-459)&JP,A,62 132727 (TOYO SODA) 16 June 1987,US5993516-A  M.W. Ackley et al., "Adsorption Characteristics of High-Exchange Clinoptilolites", Ind. Eng. Chem. Res., vol. 30, No. 12, 1991, pp. 2523-2530.;  M.W. Ackley et al., "Clinoptilolite: Untapped potential for Kinetic gas separations", Zeolites, 1992, vol. 12, Sep./Oct., pp. 780-788.EP871541-B1  DATABASE WPI Week 8833 Derwent Publications Ltd., London, GB; AN 88-230367 & JP,A,63 162 519 (TPYO SODA) , 6 July 1988;  IND. AND ENG. CHEM. RES., vol. 30, no. 12, 1991 WASHINGTON, pages 2523-2530, XP 000274307 M.W. ACKLEY 'ADSORPTION CHARACTERISTICS OF HIGH-EXCHANGE CLINOPTILOLITES';  M.H.HUBERT: "Sodium, Calcium, and Ammonium Exchange on Clinoptilolite from the Fort Laclede Deposit, Sweetwater County, Wyoming", CLAYS AND CLAYS MINERALS, , 1987, vol. 35, no. 6, pages 458 to 462;  PATENT ABSTRACTS OF JAPAN vol. 11 no. 361 (C-459) & JP,A,62 132727 (TOYO SODA) 16 June 1987,;  R.M.BARRER, R.PAPADOPOULOS, L.V.C.REES: "Exchange of Sodium in Clinoptilolite by organic cations", J.INORG. NUCL.CHEM., , 1967, vol. 29, no. , pages 2047 to 2063;  ZEOLITES, vol. 12, September 1992 pages 780-788, XP 000567633 M.W.ACKLEY 'CLINOPTILOLITE: UNTAPPED POTENTIAL FOR KINETIC GAS SEPARATIONS'