Facile and Rapid Synthesis of Cerium-Modified UiO-66-NH2 for Efficient Removal of Safranine T from Aqueous Solutions

Herein, a facile and rapid preparation method was developed to synthesize Ce-doped UiO-66-NH 2 through a one-pot solvothermal method. This approach simultaneously introduces functional groups onto organic ligands and incorporating a novel metal into metal clusters. The incorporation of Ce ions effectively enlarged the pore size and increased the pore volume, thereby facilitating the diffusion of specific adsorbate molecules into the inner adsorption sites provided by the –NH 2 groups. Due to the favorable pore structures and more exposed adsorption sites, the safranine T (ST) adsorption capacity of Ce-doped UiO-66-NH 2 was ten times higher than the pristine UiO-66-NH 2 and reached 1340 mg/g at optimal adsorption conditions, surpassing most of the reported porous adsorbents. The kinetic and isotherm fitting results showed that the pseudo-second-order and Langmuir models described the adsorption behaviors of ST best, indicating a homogeneous, endothermic, and spontaneous monolayer adsorption process. The adsorption mechanism showed that the hydrogen bonding interaction and pore filling effect are identified as the main mechanism whilst electrostatic attraction interaction further enhances the adsorption capacity at optimal pH. Therefore, Ce-doped UiO-66-NH 2 can serve as a promising adsorbent for the removal of cationic dyes from textile wastewater, and the developed facile and rapid method offers a viable strategy to construct novel MOF-based adsorbents.