Abstract: A carbon dioxide adsorbent including silica gel and an amine compound carried by the silica gel. The silica gel has a spherical shape, a particle size ranging from 1 mm to 5 mm inclusive, an average pore diameter ranging from 10 nm to 100 nm inclusive, a pore volume ranging from 0.1 cm3/g to 1.3 cm3/g inclusive, and a waterproof property N that is defined by an expression (1) and that is not lower than 45%, N=(W/W0)×100??(1) where N is the waterproof property in percentage (%) of the silica gel, W0 is a total number of particles of the silica gel immersed in water, W is a number of particles of the silica gel not subjected to breakage out of W0.

Abstract: A carbon dioxide adsorbent including silica gel and an amine compound carried by the silica gel. The silica gel has a spherical shape, a particle size ranging from 1 mm to 5 mm inclusive, an average pore diameter ranging from 10 nm to 100 nm inclusive, a pore volume ranging from 0.1 cm3/g to 1.3 cm3/g inclusive, and a waterproof property N that is defined by an expression (1) and that is not lower than 45%, N=(W/W0)×100??(1) where N is the waterproof property in percentage (%) of the silica gel, W0 is a total number of particles of the silica gel immersed in water, W is a number of particles of the silica gel not subjected to breakage out of W0.

Abstract: A method for manufacturing a carbon dioxide adsorbent includes preparing an amine aqueous solution having an amine compound concentration ranging from 5% to 70% inclusive and a temperature ranging from 10° C. to 100° C. inclusive, impregnating silica gel with the amine aqueous solution, and aeration-drying the silica gel carrying the amine compound. The silica gel has a particle size ranging from 1 mm to 5 mm inclusive, an average pore diameter ranging from 10 nm to 100 nm inclusive, and a pore volume ranging from 0.1 cm3/g to 1.3 cm3/g inclusive.

Abstract: A method for manufacturing a carbon dioxide adsorbent includes preparing an amine aqueous solution having an amine compound concentration ranging from 5% to 70% inclusive and a temperature ranging from 10° C. to 100° C. inclusive, impregnating silica gel with the amine aqueous solution, and aeration-drying the silica gel carrying the amine compound. The silica gel has a particle size ranging from 1 mm to 5 mm inclusive, an average pore diameter ranging from 10 nm to 100 nm inclusive, and a pore volume ranging from 0.1 cm3/g to 1.3 cm3/g inclusive.