RESUMO
The adsorption of hexavalent chromium (Cr (VI)) on pongamia (Pongamia pinnata) leaf powder was investigated in the present study. Crude pongamia leaf powder (CPLP) and nitric acid treated pongamia leaf powder (APLP) were used as adsorbents. CPLP did not show remarkable adsorption efficiency but APLP had good adsorption capacity and adsorption removal efficiency. The parameters studied included the contact time, initial solute concentration and pH. The optimum pH for removal of chromium was found to be 2 for both CPLP and APLP. The best contact time for maximum chromium adsorption was 165 minutes for CPLP and APLP. CPLP and APLP showed good adsorption capacity and adsorption removal efficiency at an initial chromium concentration of 5 mg/L. The adsorption was found to follow Langmuir and Freundlich isotherms for CPLP and APLP but they showed good curve fit for Freundlich isotherm.