When the initial concentration of As(V) is 5 ppm, the adsorption capacity was calculated to be 24.80 mg/g. This value is much higher than other porous adsorbents such as hybrid silica and aluminum oxide. This phenomenon could be explained that the surface of the MOF-808 nanoparticles becomes positively charged at low pH, which would enhance the electrostatic interaction of adsorbent and As(V).