Synthesis of UiO-66-NH₂@silica core-shell microspheres for rapid and efficient arsenate adsorption from aqueous solutions

Arsenic as an emerging micropollutant, causing the world ecosystems polluted due to its high toxicity to the environment. In order to removal arsenate As (V), many metal organic frameworks (MOFs) have been synthesized as adsorbents. However, the mostly existing MOFs adsorbents have a slow adsorption rate, agglomeration and poor stability in water.Therefore, it is highly desired to explore a novel adsorbent for the more efficient and rapid removal of As(V) from aqueous solution. Herein, we synthesized monodisperse microspheres with amino functionalized MOF UiO-66 on the silica core for the first time.The synthesized adsorbent was charecterised using scanning electron microscopy (SEM), transmission electron microscopy (TEM), N 2 adsorption desorption isotherms, x-ray diffraction (XRD).The obtained results revealed that it exhibit monodisperse core shell microspheres and showed fast separation of As (V) from aqueous solution. The Kinetic data showed that the As (V) removed rapidly, within 5 min only and the adsorption kinetics described by the pseudo second order kinetic model.The adsorption capacity of the adsorbent was 22.62 μg/g at pH 2. The adsorption experiment showed that adsorbent prepared with UiO-66-NH 2 @SiO 2 could rapidly remove the arsenate from aqueous solution. FTIR results indicated that As (V) is removed successfully from aqueous solution. Electrostatic interaction between UiO-66-NH 2 and As (V) should be the proposed mechanism.