Pristine orange peel was chemically modified by introducing sulfur groups with the carbon disulfide treatment in alkaline medium. The presence of sulfur groups on orange peel xanthate were identified by FTIR spectroscopic study. Equilibrium isotherms and kinetics were obtained and the effect of various parameters including equilibrium pH, contact time, temperature and initial ion concentration on adsorption of Pb2+ were studied by batch experiments. The maximum adsorption capacity of orange peel xanthate was 204.50 mg g(-1), which was found to increase by about 150% compared to that of pristine orange peel. The adsorption process can attain equilibrium within 20 min, and kinetics was found to be best-fit pseudo-second-order equation. Temperature has little effect on the adsorption capacity of orange peel xanthate. in addition, the adsorption mechanism was suggested to be complexation. (C) 2009 Elsevier B.V. All rights reserved.