Multifunctional self-cleaning Zr-Porphyrin@PG membrane for wastewater treatment

Abstract

Incorporation of three-dimensional (3D) nanoparticles into two-dimensional (2D) nanosheets can increase the number of nanofluidic channels, thereby significantly improving membrane permeability. In this study, Zr-porphyrin metal-organic frameworks (MOFs) nanoparticles were grown in-situ on a porous graphene oxide sheet structure to fabricate a multifunctional composite nanofiltration membrane. The results demonstrated that the growth of Zr-porphyrin on the porous graphene was limited, resulting in a more uniform distribution of smaller particles, and a larger specific surface area. The water permeability of the membrane was 29.2 LMH bar⁻¹, which was significantly higher than that of the thin-film composite (TFC) membrane (8.9 LMH bar⁻¹). Furthermore, the selectivity of the membrane was maintained, with a rejection rate exceeding 99.9 % for four dyes, Na₂SO₄ rejection rate of 97 %, and NaCl rejection rate of 18 %. This membrane also demonstrated a good stability in continuous operation for 72 h. In addition, the membrane displayed excellent photocatalytic and antibacterial activities. This work presents a versatile strategy for developing multifunctional composite nanofiltration membranes with high permeability, superior decolorization ability, outstanding divalent salt removal, excellent photocatalytic activity, and antibacterial properties.