Adsorbent for carbon dioxide, method of preparing the same, and capture module for carbon dioxide

A method of manufacturing an adsorbent for carbon dioxide, including a composite metal oxide, which includes a divalent first metal (M1), a trivalent second metal (M2), and an element (A) with an electronegativity ranging from about 2.0 to about 4.0 and has an amorphous structure, the method comprising:

• preparing a mixed aqueous solution by dissolving a salt of a divalent first metal and a salt of a trivalent second metal in water;
• adjusting pH of the mixed aqueous solution to be basic to precipitate a composite metal hydroxide;
• separating the composite metal hydroxide;
• mixing the composite metal hydroxide with an aqueous solution of a salt including an element with an electronegativity of about 2.0 to about 4.0 to obtain a mixture;
• adjusting pH of the mixture to be equal to or less than about 7 and stirring the mixture to prepare an ion-exchanged composite metal hydroxide;
• separating the ion-exchanged composite metal hydroxide from the mixture;
• and
• calcining the ion-exchanged composite metal hydroxide to obtain a composite metal oxide, and
• wherein the salts of the divalent first metal and of the trivalent second metal do not include a carbonate anion.