Synthesis of schiff base-functionalized ordered mesoporous silica for effective adsorption of Re(VII)

Rhenium is an important emerging metal material. The scarcity of reserves and the difficulty in separation and enrichment have always been important reasons restricting its industrial application. In this work, aminated SBA-15 is used as substrate for the crosslinking reaction to prepare a type of Schiff base-containing mesoporous dioxide silica material (GA-MMA-0.2N-SS) for high selectively recovering Re(VII) in aqueous solution. The results show that the using amount of APTES is small in the modification process of the adsorbent material, and the modified adsorbent still maintains the orderly mesoporous structure. The adsorption capacity of GA-MMA-0.2N-SS for Re(VII) up to 198.77 mg·g-1 under pH 1.5, and it can still reach more than 97% after 4 elution cycles. Adsorption mechanism study indicated that the complex reaction between N atoms and ReO4- is the main adsorption mechanism of Re(VII) on GA-MMA-0.2N-SS. This study provided a new adsorbent based schiff base and ordered mesoporous silica for the separation of Re(VII) from mixed solution, which also provides new ideas for the design of adsorbents in the future.