抄録
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 (pH = ca.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.
