A filtration device including a fluid-impermeable housing having a gas inlet and outlet, and containing within the housing first filter media particles of an extended surface area substrate and containing at least one metal impregnant, and second filter media particles of an extended surface area zirconium hydroxide substrate. The device may be used in atmospheres containing various harmful gases, and may provide particularly useful improvements in NO.sub.x breakthrough times compared to a device containing only the first filter media particles or only the second filter media particles.

A device for removing carbon dioxide from the air has a reaction chamber having closed sidewalls and a removable end wall. There is a removable adsorber unit disposed in the reaction chamber that comprises an adsorbent mixture containing soda lime mixed with activated charcoal, and an air-permeable outer covering surrounding the adsorbent mixture. A louvered bed is disposed above the adsorber unit in the reaction chamber. The louvered bed has openings between angled louvers for directing air above the louvered bed into the removable adsorber unit. Air flowing into the reaction chamber is directed toward the adsorber unit by the louvered bed, so that the air flows between the louvers, through the openings and into the adsorber unit where the carbon dioxide in the air is adsorbed and removed from the atmosphere.

A device for removing carbon dioxide from the air has a reaction chamber having closed sidewalls and a removable end wall. There is a removable adsorber unit disposed in the reaction chamber that comprises an adsorbent mixture containing soda lime mixed with activated charcoal, and an air-permeable outer covering surrounding the adsorbent mixture. A louvered bed is disposed above the adsorber unit in the reaction chamber. The louvered bed has openings between angled louvers for directing air above the louvered bed into the removable adsorber unit. Air flowing into the reaction chamber is directed toward the adsorber unit by the louvered bed, so that the air flows between the louvers, through the openings and into the adsorber unit where the carbon dioxide in the air is adsorbed and removed from the atmosphere.

An adsorption vessel comprising a packed bed region of adsorbent particles contiguously arranged, comprising a perforated adsorbent particles, a gas separation process using the perforated adsorbent particles, and methods for making the perforated adsorbent particles. The perforated adsorbent particles each comprise an adsorbent material where the perforated adsorbent particles each have at least 10 channels extending through the particle. The equivalent diameter of the channels may range from 0.05 mm to 1.5 mm, and the void fraction of the channels may range from 0.05 to 0.5.

An adsorption vessel comprising a packed bed region of adsorbent particles contiguously arranged comprising a perforated adsorbent particles, a gas separation process using the perforated adsorbent particles, and methods for making the perforated adsorbent particles. The perforated adsorbent particles each comprise an adsorbent material where the perforated adsorbent particles each have at least 10 channels extending through the particle. The equivalent diameter of the channels may range from 0.05 mm to 1.5 mm, and the void fraction of the channels may range from 0.05 to 0.5.

A method for purifying a crude hydrogen feed stream utilizes an adsorbent having a N2/Ar selectivity ranging from 2 to 4 at 30 C. and a Henry's law coefficient for argon ranging from 0.15 to 1.0 mmole/g/atma at 30 C. The composition of crude hydrogen streams from processes in which carbon dioxide is captured necessitates new criteria for adsorbent selection to improve recovery.