Abstract In this study biochar was selected as the supporting media for the adsorption of hexavalent chromium (Cr6 +). Biochar is a favored adsorbent due to its high surface area and pore volume. It has created using a pyrolysis process, heating biomass in a low oxygen environment. Two types of agricultural waste, oleaster seed biochar (OSBC) and cherry stone biochar (CSBC) were prepared by using the carbonization method. Structure of biochars was analyzed via the SEM, FTIR analyses and surface area of the biochars was determined by BET analysis. Adsorption performances of biochars were examined by the batch type reactors. The effect of the initial pH Cr6 + concentration, adsorbent amount and contact time on the adsorption process were studied. The maximum amount of removed Cr6 + ions from the solution within 150 min was found to be 84.2% for OSBC, 81.3% within 180 min for CSBC when the initial pH of the solution was maintained at 1.5. Kinetic adsorption of chromium onto biochars was elucidated. The experimental data followed the pseudo-second-order rate kinetics.