The biosorption of Cu(II) onto chestnut shell, a residue of the food processing industry, in a batch adsorber has been studied. Equilibrium isotherms, kinetic data, and thermodynamic parameters have been evaluated. Equilibrium data agreed well with Langmuir isotherm and Redlich–Peterson isotherm models. The adsorption capacity of chestnut shell for Cu(II) was determined with the Langmuir model and was found to be 12.56 mg g−1 at 293 K. The kinetic data were found to follow the pseudo-second-order model. Intra-particle diffusion is not the sole rate-controlling factor. Gibbs free energy was spontaneous for all interactions, and the adsorption process exhibited exothermic enthalpy values. Chestnut shell was shown to be a promising biosorbent for Cu(II) removal from aqueous solutions.

Keywords: Biosorption; Chestnut shell; Copper; Isotherm; Kinetics; Thermodynamics