Food waste is discharged abundantly, and while some of it is reused, most is incinerated. The recycling of soybean waste and wheat bran as vegetable biomass needs to become established, and the ability to remove Cd2+ and Cu2+ by vegetable biomass needs to be estimated. The estimations performed here revealed that the amounts of Cd2+ and Cu2+ adsorbed onto untreated vegetable biomass were larger than those adsorbed onto defatted biomass. This indicates that the adsorption of Cd2+ and Cu2+ onto vegetable biomass may depend on fat content. On the other hand, the elution percentage of vegetable biomass increased as the concentration of hydrochloric acid increased. The elution is due to the degradation of protein in the biomass by the acid. The amounts of Cd2+ and Cu2+ adsorbed decreased as more than 0.10 mol/L of the concentration of hydrochloric acid increased. Cd2+ and Cu2+ are adsorbed on vegetable biomass by their adsorption onto protein. The amounts of Cu2+ adsorbed onto soybean waste and wheat bran in a binary-solution system are larger than those in a single-solution system. However, less Cd2+ was adsorbed onto wheat bran in the binary system than in the single one. These results indicated that the amount of Cu2+ adsorbed increases in the presence of Cd2+. Either the adsorption of Cd2+ onto wheat bran is inhibited by Cu2+ or the adsorptions of Cd2+ and Cu2+ onto the biomass were affected by each other. (C) 2009 Elsevier B. V. All rights reserved.