Preparation mechanism of spherical amorphous ZrO(OH)2/AlOOH hybrid composite beads for adsorption removal of sulfate radical from water

To circumvent the liquid-solid separation and dispersion of the powdered adsorbent during adsorption-desorption circulation, using a drop-oil sol-gel method, the spherical ZrO(OH) 2 /AlOOH hybrid composite beads were prepared as an adsorbent for sulfate adsorption removal from water. The preparation mechanism was proposed and discussed in term of the characterization results showing that the as-prepared beads is an amorphous mesoporous material constructed from nanoflakes composed of rod-like nanoparticles, and possesses a good sphericity, a relatively high specific surface area (195.56 m 2 /g) and adequate mechanic strength (Zr/Al(0.2)-30-3.5, 32.1 N). The adsorption tests indicated that the saturated adsorption capacity increases with sulfate concentration and decreases with prolongation of adsorbent drying time, owing to the reduction of water content, the maximum adsorption capacity can reach 205 mg/g (Zr/Al(0.2)-30-2). This work has a profound significance for the further research and industrial application of spherical adsorbent related to hydrate zirconia in fixed adsorption bed.