Caffeine-adsorbing materials, caffeine-adsorbing systems, and decaffeination system suitable for removing caffeine from a solution; methods for removing caffeine from a solution; and methods of making the caffeine-adsorbing materials are described.說明吸附咖啡因之材料、吸附咖啡因之系統及適合用於自一溶液中去除咖啡因之去咖啡因之系統;用於自一溶液中去除咖啡因之方法;以及製造該吸附咖啡因之材料的方法。