In the present study the removal of Cr(III) and Cr(VI) using Daucus carota L. (carrot) waste biomass was investigated from aqueous Solutions Biosorption studies were determined as a function of contact time. pH. initial metal ion concentration. biosorbent size and biosorbent dose. Maximum uptake capacity of D. carota L waste biomass for Cr(III) (86 65 mg/g) and Cr(VI) (88 27 mg/g) was observed at pH 1 and 5 respectively. Optimum biosorbent dose (0.1 g), biosorbent size (0.250 mm), initial concentration (100 mg/L), temperature (30 degrees C) and contact time (240 min) gave maximum biosorption. The sorption isotherms followed the langmuir type suggesting monolayer sorption character A high degree of correlation coefficient was obtained for the second-order kinetic model To evaluate the effect of pretreatment oil Cr(III) and Cr(VI) uptake by D carota L., the waste biomass was physically as well as chemically pretreated Maximum Cr(III) and Cr(VI) uptake was observed with acetone and Moringa oleifera extract pretreated D carota L. waste biomass. The results also demonstrate that chromium uptake capacity of D. carota L waste biomass was comparatively higher than most of early reported work (C) 2009 Elsevier B.V. All rights reserved