At the study pH, for arsen, the adsorption equilibrium was gained after 90 min. Kinetic data fitted well to the pseudo-secondorder reaction model. The adsorption of γ- FeOOH for As (V) and As(III) could be competed by some other ion such as sulfate, ammonium and chloride. The high adsorption capability and good performance on other aspects make the γ- FeOOH nanorod a promissing adsorbent for the removal of As (V) and As(III) from the groundwater. | Science & Technology Development, Vol 19, Adsorption of As(V) and As(III) from aqueous solution by lepidocrocite (γFeOOH) nanoparticle Nguyen Dinh Trung Truong Dong Phuong Institute of Evironmental Research, Dalat University (Received on 1st October 2015, accepted on 2 th December 2016) ABSTRACT γ-FeOOH nanorods an adsorbent for As(V) and As(III) removal was prepared by a chemical co-precipitation method. The maximum adsorption capacities at pH6 for As(V) and As(III) were and mg/g, respectively, higher than those of Fe2O3, Fe3O4. The adsorption data accorded with Freundlich isotherms. At the study pH, for arsen, the adsorption equilibrium was gained after 90 min. Kinetic data fitted well to the pseudo-secondorder reaction model. The adsorption of γFeOOH for As (V) and As(III) could be competed by some other ion such as sulfate, ammonium and chloride. The high adsorption capability and good performance on other aspects make the γFeOOH nanorod a promissing adsorbent for the removal of As (V) and As(III) from the groundwater. Keywords: As (V), As(III), sorption, kinetic, γ-FeOOH nano INTRODUCTION Geogenic arsen (As) contamination in the groundwater is a major health problem that has been recognized in several regions of the world, especially in Bangladesh, West Bengal [1, 2], Vietnam [3-5], Cambodia [6, 7], Myanmar [8], and Mexico, where a large proportion of groundwater is contaminated with arsen at levels from 100 to 2000 μg L-1 [9]. In natural water, arsen is primarily present in inorganic forms and exists in two predominant species, arsenate As(V) (H3AsO4, H2AsO4-, HAsO42-) and arsenic As(III) (H3AsO3, H2AsO3-, HAsO32-) [10, 11]. As(III) is much more toxic and mobile than As(V). However, in the groundwater in nature, after exposure to air, the majority As(III) was transferred to As(V) [12]. Iron oxides indeed have been used for arsen removal [13-17] as well as, alumina [15], zeolite, titanium dioxide [18], and akaganeite [19]. .
