A study of copper(II) adsorption equilibrium in aqueous solutions was made on dead fungal biomass of Pleurotus pulmonarius CCB019 and Schizophyllum commune in batch systems. A fractional factorial design 2(4-1) based in preliminary experiments (kinetic and precipitation studies) was made to verify the influence on the response variable of the four factors studied in adsorption process: pH (2.0 and 4.0), temperature (30 and 50 degrees C, initial metal concentration (4 and 100 mg l(-1)) and biomass concentration (0.5 and 3.0 g l(-1)). The response measured was the concentration of metal removed after a contact time of 12 h, with either the P pulmonarius or the S. commune biomass. Based on results obtained from the fractional factorial design, the experimental conditions used in adsorption isotherm construction were: pH 4.0, temperature 50 degrees C, biomass concentration 3 g l(-1). The initial metal concentration was varied between 5 and 200 mg l(-1). The experimental data was best adjusted by Langmuir model for both biomass. (c) 2005 Elsevier Ltd. All rights reserved.