ZIF-67/SA@PVDF Ultrafiltration Membrane with Simultaneous Adsorption and Catalytic Oxidation for Dyes
Kaixuan Zhu, Shabin Mohammed, Hai Tang, Zongli Xie, Sisheng Fang, Shasha Liu
Abstract
Due to their stable chemical properties and complex structures, dyes are difficult to be removed from water. Herein, a ZIF-67/SA@PVDF (ZSA3@PVDF) mixed matrix membrane has been fabricated by incorporating silicon aerogel (SA) and zeolitic imidazolate framework material 67 (ZIF-67) nanoparticles in a polyvinylidene fluoride (PVDF) membrane for the removal and degradation of dyes from water. The influence of SA and ZIF-67 on the morphology and structure of the membrane was confirmed using scanning electron microscope (SEM) and atomic force microscope (AFM). In ZSA3@PVDF membrane, both SA and ZIF-67 are highly porous nanomaterials that possess good adsorption capacity, as confirmed by the Brunauer–Emmett–Teller (BET) result. In addition, the cobalt (Co) element of ZIF-67 can catalyze peroxymonosulfate (PMS) to generate strong oxidizing sulfate radicals (SO42−), contributing to improving regeneration capacity of the ZIF-67/SA@PVDF membrane. The water flux of ZSA3@PVDF membrane is 427.6 L m−2 h−1 bar−1, and the Methylene blue (MB) removal rate is higher than 99% when filtrating 100 mL MB solution (5 mg/L). The regeneration test result shows that the removal rate of the ZSA3@PVDF membrane is still above 98% after five cycles of adsorption of MB. The self-cleaning experiment shows that the adsorption of SA in the ZSA3@PVDF membrane promotes the catalytic performance of the membrane, showing a better self-cleaning ability. The ZSA3@PVDF membrane provides a new strategy for the removal of dyes in the advanced purification of dye wastewater.