Adsorptive materials have been widely investigated for removing heavy metal water pollutants and agricultural residues such as fruit peels seems to be a promising alternative due to its low cost and availability. This work attempts to study kinetics of Cr (VI) adsorption onto different orange peels-based biosorbents (OP, OPAC and OP-Chitosan). The activated carbon from orange peels was obtained by carbonizing the biomass and its activation with H3PO4 acid solution. The OP-Chitosan was prepared

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... y immersing orange peels into chitosan-acetic acid gel. The OP biomass was characterized by ultimate analysis in order to determine the composition of main elements (carbon, nitrogen and hydrogen). Batch experiments were carried to analyse adsorption process over time and fit the experimental data to kinetic models such as pseudo-first order, pseudo-second order, Elovich and intraparticle diffusion. It was found that elemental composition of orange peels biomass was C (%) 42.02, H (%) 5.44 % and N (%) 0.7. The pseudo-second order model best fits adsorption results for OPAC and OP-Chitosan with ,2 value of 17.27 and 17.24 mg/g, respectively. For OP biosorbent, pseudo-first order describes appropriately the data with parameter ( ,1 ) value of 18.21 mg/g.