In-situ growth of UiO-66-NH2 in porous polymeric substrates at room temperature for fabrication of mixed matrix membranes with fast molecular separation performance

Abstract

In-situ growth of UiO-66-NH2 in ordinary porous polymeric substrates offers promising opportunities to eliminate interfacial defects in mixed matrix membranes (MMMs). However, this strategy is still hard to be realized because conventional hydrothermal synthesis of UiO-66-NH2 involves harsh conditions (e.g., high temperatures, and polar aprotic solvents), which are destructive to ordinary polymer. Herein, UiO-66-NH2 was in-situ grown in polymeric substrates under room temperature via a successive immersion of a porous polyether sulfones substrate in a Zr4+ formic acid/ethanol solution and a 2-aminoterephthalic acid ethanol/formic acid/water solution. Attenuated total refraction Fourier transform infrared and X-ray diffraction characterizations demonstrated the successful incorporation of UiO-66-NH2 in the substrate. The optimized membrane possessed a high pure water permeance of 209.5 L-2h−1 bar−1 and rejections higher than 99.5% towards small molecules of Congo Red, xylene brilliant cyanin G, and Rose Bengal sodium salt. More importantly, after a 5-day immersion in water or an intense ultrasonication treatment, the membrane showed no significant change in separation performance, suggesting its excellent stability. The novel strategy regarding MMMs with UiO-66-NH2in-situ growth disclosed in this study paves the way to develop advanced UiO-66-NH2 membranes toward sustainable molecular separation in environmental applications.