TECHNOLOGY FOCUS - CHEMICAL ENGINEERING - Preferred Process: The process is carried at 0-150degreesC and comprises the following steps (a), (a1), (b), (b1), (b2), (c), (d) and (e) in the said sequence. AZ is pressurized to super atmospheric pressure with feed gas mixture and/or AGDS prior to step (a). Step (a) is carried out a pressure of 2-20 bara and purge effluent (A) and/or (B), purge effluent (D), AGDS from step (b1) and an additional AGDS is introduced into AZ. In step ( a1) AZ is partially depressurized to produce AGDS and AZ is further partially depressurized between step (a) and (a1) to produce an additional AGDS. AZ is purged with purge effluent (A) and/or (B) between step (a1) and (b) to produce purge effluent (C). In step (b1) AGDS from (a1) is passed cocurrently through AZ to produce an AGDS. In step (b2) AZ is purged by cocurrently passing purge effluent (C) to produce effluent (D). Step (b) and (e) are carried out by counter currently depressurizing AZ at pressure of 50 millibara-5bara, preferably about 1 bara by using same vacuum pump. In step (a1), (c) and (d) gas flows cocurrently through AZ. Preferred gas: The adsorbable gas is carbon monoxide. The feed gas is a mixture containing carbon dioxide and/or methane and hydrogen.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred adsorption zone: The process includes AZ(s) comprising at least four absorption zones which are arranged parallel and operated out phase. The AZ comprises a porous substrate and adsorbent. The substrate is selected from carbon, silica gel, alumina, zeolites or their mixtures. The adsorbent is a ion of copper, silver, palladium or their mixture, preferably copper and/or silver containing alumina. EXAMPLE - A feed stream containing carbon monoxide 11.3%, methane 4.1%, carbon dioxide 10.5% and remaining hydrogen was introduced into an adsorption vessel at pressure of 18 bara and flow rate of 2.53 slpm. The adsorption vessel was made to contain beds, each containing 1500 cm3 of copper ion-exchanged type Y zeolite operated at half-cycle time of 58 min and at 80degreesC. The cycle comprised the steps of feed pressurization, adsorption, cocurrent depressurization, purging of effluent gases, evacuation, idles, cocurrent feeds with evacuation of effluent gases and cocurrent feed with strongly adsorbed gas product. The gas flow rate of strongly adsorbed product was 0.216 slpm and the adsorbed product was found to contain 99.2% of carbon monoxide, 130 ppm of methane, 0.62% of carbon dioxide and 1900 ppm of hydrogen. This showed that the process enables recovery of highly pure carbon monoxide in high yield by the use of single vacuum pump.