This paper investigates the sorption behavior of As(III) and As(V) on granular activated carbon, quartz sand and zeolite impregnated with Fe–Mn binary oxide (GAC-FeMn, S-FeMn and Z-FeMn). The sorbents was prepared relatively simply by simultaneous oxidation and coprecipitation method. Brunauer-Emmett-Teller (BET) analysis showed that the surface areas of the GAC-FeMn, S-FeMn and Z-FeMn were 996 m2/g, 0.430 m2/g and 55.2 m2/g, respectively. Kinetic experiments (conventional batch technique) were performed with 10 mg of sorbent and 200 µg/l As(III) or As(V) solution at pH 7.0±0.2. In the sorption isotherm study, the adsorbent doses were varied from 0.5-25 g/L, with the same initial As(III) and As(V) concentrations. Pseudo-first order, pseudo-second order, Elowich and intraparticle diffusion models were employed to fit the kinetic data, in order to elucidate the sorption mechanism and potential rate controlling steps such as mass transport and diffusion control processes. The data from the adsorption kinetics best fit with the pseudo-second order model for both As(III) and As(V), suggesting chemical adsorption on the surface of the GAC-FeMn, S-FeMn and Z-FeMn. Intraparticle diffusion model data showed that diffusion was not the only rate-limiting step in the adsorption process. Langmuir and Freundlich models were employed to fit the equilibrium adsorption data, with the Freundlich model giving a better representation, possibly due to irreversible adsorption and the heterogeneous nature of the adsorbents. KF values, rough indicators of sorption capacity, were in the following order: GAC-FeMn>Z-FeMn>S-FeMn for both As(III) and As(V).
