Patents
A process for the preparation of a molecular sieve adsorbent for the size/shape selective separation of air. The invention relates to a process for the preparation of a molecular sieve adsorbent for the size/shape selective separation of air. The invention relates to the use of pore engineered zeolites as size/shape selective adsorbents in the separation of gases having closely related physical properties. In the invention inventive features to obtain the molecular sieve adsorbent is by the control of the pore mouth of the zeolite (i) by the deposition of silica by chemically reacting an alkoxide with silanol groups present on the external surface of the zeolite followed by calcination at 450-650°C, (ii) by liquid phase chemical reaction of tetra alkyl orthosilicate in a moisture free solvent to ensure uniform deposition of silica on the surface of the zeolite at ambient conditions, (iii) enhancement of thermal and hydrothermal stability of the adsorbent by silica deposition on the external surface of the zeolite, (iv) to prepare a zeolite based oxygen selective adsorbent based on shape/size selectivity by a method other than conventionally used cation exchange.