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).
the XRD patterns of the samples obtained in the present work exhibit broad Bragg reflections, suggesting the presence of crystals with small sizes, which was in agreement with the SEM and TEM results. From Fig. 1(f), it could be seen that the peak of the samples B exhibited little intensity change after five cycles, indicating that their microcrystalline form was well remained.