UiO-66(Zr)-derived t-zirconia with abundant lattice defect for remarkably enhanced arsenic removal

Zirconium oxide (ZrO2) exhibits great potential in the remediation of arsenic-polluted water. In this study, tetragonal zirconium oxide (t-ZrO2) with high lattice defects was facilely fabricated by regulating the Zr-metal-organic framework (MOF) (UiO-66) with sodium acetate modulator and examined to adsorb arsenic from water. Benefitting from the synergistic effects of mesopores structure and lattice defect, t-ZrO2 exhibited ultrahigh adsorption capacity and faster kinetics towards both arsenate (As(V)) and arsenite (As(III)). The Langmuir adsorption capacity for As(V) and As(III) of 147.5 mg g(-1)- and 352.1 mg g(-1)- on t-ZrO2 in exothermic process, respectively, significantly outperforming reported counterparts in literature (generally <= 100 mg g(-1)). The faster adsorption kinetic of both As(III) and As(V) on t-ZrO2 is defined favorably by the pseudo-second-order model over a wide pH (3-11). Furthermore, arsenic is mainly captured by t-ZrO2 via forming Zr-O-As bonds through occupying coordinatively unsaturated zirconium atoms adsorption sites revealed by the X-ray photoelectron spectroscopy (XPS) spectrum and Fourier-transformed infrared (FTIR) spectra analysis. This study offers a new strategy for designing ultrahigh performance Zr-MOF-derived adsorbents for capturing arsenic.

Automated summary

Zirconium oxide with high lattice defects, t-ZrO2, synthesized by regulating Zr-MOF UiO-66, demonstrated ultrahigh adsorption capacity towards arsenic, outperforming existing counterparts in literature. The adsorption of both As(III) and As(V) is facilitated by the mesoporous structure and lattice defect of t-ZrO2, with favorable pseudo-second-order kinetics over a wide pH range. The formation of Zr-O-As bonds on t-ZrO2 was revealed to be the main mechanism for arsenic capture, offering a new strategy for designing high-performance Zr-MOF-derived adsorbents.