Functionalized and Monodispersed Mesoporous Silica Nanospheres with a Schiff-Base for Metal Ion Adsorption

Mesoporous silica nanospheres (MSNs-AH) with a Schiff-base ligand were synthesized using a snap-top strategy and post-synthetic grafting strategy for metal ion adsorption. The mesoporous MSNs-AH with the Schiff-base ligand were used for the adsorption of metal ions from artificial wastewater and artificial seawater. The adsorption characteristics of the functionalized adsorbents for various metal ions were tested for different adsorption times (1~48 h) in artificial wastewater and artificial seawater. In the case of artificial wastewater, the functionalized adsorbents had no preferential selectivity for metal ions except for Na+ ions, even though the MSNs-AH adsorbent adsorbed most of the metal ions investigated in this work, including Li⁺, Co²⁺, Ca²⁺, Fe³⁺, Mn²⁺, Mg²⁺, Al³⁺, Zn²⁺, and Ni²⁺. In the case of artificial seawater, however, the MSN absorbent showed high selectivity for Li⁺ ions.