In-situ growth of three-dimensional copper-based catalyst in 4A zeolite/PES mixed matrix membrane for Fenton-like degradation of phenol

Abstract

Fenton-like membrane reactors applied to water purification provide a broad solution to address the challenges of catalyst recovery, low reaction efficiency, and high mass transfer resistance in heterogeneous batch reactions. Zeolites as nanocatalyst carriers are promising candidates for advanced purification membranes. Herein, we report a composite catalytic membrane (4A-Cu/PES) for Fenton-like degradation of phenol wastewater, fabricated by in-situ growth of copper nanoflowers on a 4A zeolite/polyethersulfone (PES) mixed matrix membrane, forming a three-dimensional core-shell nanostructured catalyst. Compared with the conventional method, the in-situ growth prevents the copper catalyst from being covered by the polymer and significantly increases the copper loading (3.97 %), thus ensuring efficient catalytic reactions within the membrane pores. Meanwhile, the porous structure of zeolite provides a large specific surface area, facilitating uniform dispersion of copper ions during in situ growth of the catalyst and providing abundant active sites. The membrane exhibited a phenol degradation rate of 93.9 % at pH 6, significantly broadening the pH applicability of the Fenton reaction. Hydroxyl radicals (·OH) were identified as the primary active species in the 4A-Cu/PES-H₂O₂ system. Moreover, the membrane retained high catalytic activity after five cycles, demonstrating excellent stability. This work provides important insights for designing efficient and stable Fenton-like zeolite catalytic membranes.