UiO-66-NH₂-Embedded Nanofibrous Membrane for Cr(VI) Adsorption and Visible-Light Photocatalytic Reduction

The environmental challenges caused by hexavalent chromium [Cr(VI)] cannot be ignored. Here, a novel oxidized PASS (OPASS)/UiO-66-NH2 nanofibrous membrane (OPASS/U NM) was successfully fabricated by electrospinning and an in situ growth process and applied for the removal of Cr(VI). It is found that the OPASS/U NM exhibits high adsorption performance due to its large surface area. Meanwhile, UiO-66-NH2 particles are seamlessly and uniformly embedded on the surface of the OPASS fiber, which would endow the OPASS/U NM with photocatalysis reduction performance. Thus, under visible light, the OPASS/U NM could rapidly absorb Cr(VI) and reduce it to Cr(III), and the maximum removal capacity at pH 3.0 reached 20.10 mg/g. Furthermore, a possible photocatalytic reaction mechanism for removal of Cr(VI) is proposed. The OPASS/U NM also exhibits good stability, outstanding solvent resistance, and excellent recyclability. It retains a 92% reduction efficiency even after three cycles and shows a high recovery rate (>95%). More importantly, it can endure a series of strong polar solvents such as dimethylacetamide, N-methylpyrrolidone, and N,N-dimethylformamide. This research not only offers a strategy for enhancing the removal of Cr(VI) but also introduces a composite membrane suitable for wastewater containing aggressive solvents.