Magnetic MXene-NH2 decorated with persimmon tannin for highly efficient elimination of U(VI) and Cr(VI) from aquatic environment

Herein, a magnetic MXenes based composite (Fe3O4@Ti3C2-NH2-PT) was constructed by loading Fe3O4 nanoparticles into the interlamellar spacing of persimmon tannin-functionalized Ti3C2-NH2. The structure, morphology and physicochemical properties of the as-prepared adsorbents were probed by advanced spectroscopy techniques, while the impact of various experimental conditions like pH values, amount of adsorbent and contact time on the removal trend were examined by batch experiments. The elimination results revealed that Fe3O4@Ti3C2-NH2-PT could be applied in a wide range of initial concentrations, and exhibited outstanding removal efficiency for U(VI) (104.9 mg/g, pH = 5.0) and Cr(VI) (83.8 mg/g, pH = 2.0). Meanwhile, the adsorption process was described well with the Langmuir isotherm and Pseudo-second-order kinetics models, which indicated that the monolayer chemical adsorption occurred during elimination of the two contaminants. The spectral analysis results manifested that elimination of U(VI) followed an inner-sphere configuration, whereas uptake of Cr(VI) was determined by electrostatic interaction and adsorption-reduction process. This work opened a new opportunity in designing MXenes based adsorbents in the application for environmental remediation.

Automated summary

A magnetic MXenes based composite (Fe3O4@Ti3C2-NH2-PT) was developed by loading Fe3O4 nanoparticles into persimmon tannin-functionalized Ti3C2-NH2. Batch experiments showed that the composite exhibited high removal efficiency for U(VI) and Cr(VI) under various conditions. The adsorption process followed the Langmuir isotherm and Pseudo-second-order kinetics models, suggesting different elimination mechanisms for U(VI) and Cr(VI).