Development of alumina-based ceramic microspheres as adsorbent for the removal of Zn²⁺, Ni²⁺, and Mn²⁺ ions in a fixed-bed column system

Heavy metals are among the most harmful pollutants to the environment and human health. They are present in various industrial processes, requiring increasingly efficient treatments for removing their excessive concentration at acceptable levels before disposal. Adsorption is a widely used technique due to its efficiency, selectivity, and low cost. In this work, alumina ceramic microspheres, both pure and Si-doped, were produced by internal gelation to serve as adsorbents in the treatment of aqueous effluents containing Zn²+, Ni²+, and Mn²+, originating from the tri-cationic phosphatization process in the automotive industry. These microspheres, calcined at 600 °C and 700 °C, were characterized according to size distribution, specific surface area, gas adsorption, XRD, SEM, and optical microscopy. The effluent was treated in a fixed-bed column filled with these microspheres. The concentration of the three heavy metals was reduced by more than 90%, indicating the high efficiency of alumina ceramic microspheres as adsorbents of these heavy metals.

Keywords:
Adsorption; heavy metals; fixed-bed column; alumina ceramic microspheres; internal gelation