Fabrication of Biomimetic Giant Waterlily Cellulosic Adsorption-Catalytic Material for Efficient Water Purification

Abstract

Efficient treatment of heavy metal complex contamination is crucial for water purification. Herein, a biomimetic giant waterlily cellulosic adsorption-catalytic material (ACM) with nanoconfinement effect was fabricated by amino functionalized cellulose as the outer shell, and hydroxyapatite and titanium dioxide as the inner layer. The ACM demonstrated excellent ability for the efficient purification of water contaminated with heavy metal complexes. Its photocatalytic functionality facilitated rapid degradation of tetracycline, breaking its chelating structure with metal ions such as Cu(II), Cd(II), Pb(II), and Cr(VI). Subsequently, the released Cr(VI), which trapped free radicals, was preferentially adsorbed onto the ACM, then Pb(II) and Cu(II), while Cd(II) which promoted free radical production, exhibited a delayed stepwise capture effect. Interestingly, the bridging interactions between tetracycline and cationic heavy metal ions on the ACM generated a nanoconfinement effect for free radicals, which was conducive to reducing the mass transfer distance between the free radicals and tetracycline in the confined space. Therefore, the ACM effectively catalyzed the photodegradation of tetracycline and removed heavy metal ions, resulting concentrations of Cu(II), Cd(II), Pb(II), and Cr(VI) satisfies World Health Organization’s guidelines for drinking-water quality (WHO GDWQ). Overall, the proposed strategy provides new insights into the water purification of the heavy metal complex contamination.

Keywords: Heavy metals, Tetracycline, Complex contamination, Cellulose-based material, Water purification