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Removal of Copper (II) and Cadmium (II) in Water by Use of Roasted Coffee Beans

Mayumi MINAMISAWA*, Sugiko NAKAJIMA, Yuki MITSUE, Kazue MIYAZAWA, Keiko UENO, Ai HATORI, Saeko MIYAJIMA, Makie HOSHINO, Shoichiro YOSHIDA† and Nobuharu TAKAI††

Tokyo College of Medico-Pharmaco Technology; 6-5-12 Higashikasai, Edogawa-ku, Tokyo 134-8530 Japan
† Institute of Industrial Science, The University of Tokyo; 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505 Japan
†† Department of Biotechnology, College of Science and Engineering, Tokyo Denki University; Hatoyama, Hiki-gun, Saitama 350-0394 Japan

Adsorption behavior of heavy metals on arabica and robusta roasted coffee beans treated in 5 roasting degrees was investigated. The coffee beans residue after extraction with hot water were suspended in aqueous solutions (pHca.6.6) containg Cu (II) or Cd (II) and the amount of heavy metal remaining in the solution was determined on an atomic absorption spectrophotometer. Adsorption ratios of Cu (II) were 60.5 and 79.6% for the light and French roasted coffee beans of Indonesia robusta employed as adsorbent, respectively. However, when the roasted coffee beans were washed with distilled water and then air-dried prior adsorption experiments, the adsorption ratios of Cu were 92.2 and 92.6%, respectively and that of Cd was 95.6 and 97.0%. Thus, the heavy metals were almost removed from aqueous solution by use of the roasted coffee beans with washing and drying treatments.


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