The objective of this study was to evaluate the ability of the poultry litter biochar (PLB) to adsorb cadmium (Cd2+) in aqueous solutions under different experimental conditions including the following factors: Cd2+ concentration (5 - 45 mg L-1), solution pH (3 - 7), contact time (2.5 - 2.5 h) and amount of adsorbent (0.5 - 2.5 g biochar) which were modeled by the response surface methodology (RSM). A Central composite design (CCD) was used for experimental runs to optimize the factors studied. Only the mass of the adsorbent and the initial concentration of Cd influenced significantly the process of adsorption of this ion by the PLB. The optimal experimental conditions were found combining a concentration of 45.0 mg L-1 of cadmium with 0.5 g of the adsorbent, which corresponds to a maximum adsorption of 1.59 mg g-1 of the studied metal.
