The Cr (VI) adsorption characteristics of platanus orientalis leaves and their ash were examined as a function of contact time, initial pH and metal ion concentration. Batch adsorption experiments were performed. The effects of Ca²⁺, Mg²⁺, Na⁺ and K⁺ on adsorption were studied. The effect of this adsorbent on COD in wastewater showed that 2g/L of adsorbent caused increase of 110mg/L and 76mg/L COD in deionized water in 120 minutes for platanus orientalis leaves and their ash , respectively. The maximum removal took place in the pH range of 6-7, contact time of 60 minutes and initial concentration of 2mg/L. Studies showed that the Freundlich adsorption model better fitted with the results than Langmuir with R² > 0.85. The study showed platanus orientalis leaves ash was more favorable than living ones as well as in removing chromium from the aqueous solution.