Arsenic is one of the most toxic environmental pollutants. This element enter the water resources via different ways such as rocks weathering or direct discharge of industrial wastewater from mining, metal melting, glass and ceramics, paint and pesticide manufacturing, oil refineries and organic chemical industries. It causes a serious threat to human health worldwide, especially in developing countries where the supply of drinking water for a high proportion of the population depends on groundwater resources. Various processes such as precipitation, ion exchange, chemical oxidation, adsorption, etc. have been used for removing arsenic from aqueous solutions. Adsorption by biological and mineral materials has appeared to be an effective technology for removal of arsenic from aqueous solutions especially at low concentration. Simple design, no sludge production and relatively low cost are known as the advantages of adsorption processes. Choosing an appropriate sorbent is one of the important principles of sorption process. In this study, the nanoparticles of titanium dioxide - anatase (Anatase-TiO 2 ) and a hybrid combination of anatase nanoparticles with single-wall carbon nanotubes (SWNT) were used for adsorption of As III (arsenite) and As V (arsenate) from water and industrial wastewater using batch and column methods. Some of physical, chemical and morphological properties of sorbents were characterized by the X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The different parameters affecting adsorption including equilibrium time, pH, initial arsenic concentration, amount of adsorbent and the presence of disturbed ions were investigated. The adsorption isotherms were described by Langumir and Freundlich models. The adsorption kinetics showed that arsenite and arsenate sorption by both nano-adsorbents is fast. Arsenic adsorption was dependent on the initial pH of solution so that the optimum pH for arsenite and arsenate removal by both nano-adsorbents was in the range of 7.0-9.5, and 3.0-8.0, respectively. Arsenate adsorption by nano dioxide titanium and the hybrid as well as arsenite adsorption by the nano dioxide titanium were fitted by the Langmuir model (R 2 = 0 .95), while the arsenite adsorption by hybrid did not follow the two models. The maximum arsenite adsorption by anatase and hybrid was 79.6 and 75.8 mg/g (at pH= 7), and for arsenate were 113.0 and 92.4 mg/g (at pH=4), respectively. The increase of sorbent amount had no significant effect on adsorption of arsenite and arsenate. The presence of copper, lead, zinc, chromium, cadmium and nickel cations in the solution (at the concentra¥ Key Words : Arsenic, Adsorption, Nano Titanium Dioxide, Carbon Nanotubes, Langmuir and Frundlich Isotherm