Enhanced removal of organic micropollutants using 2D metal-organic framework interlayered nanofiltration membrane

Abstract

<p>Organic micropollutants (OMPs) present considerable threats to both human health and the environment. Traditional thin film composite (TFC) nanofiltration (NF) polyamide membranes, despite their high water permeance and salt rejection capabilities, often fail to effectively remove OMPs. This study addresses this limitation by incorporating two-dimensional (2D) zinc(II) tetrakis(4-carboxy-phenyl)porphyrin (Zn-TCPP) metal-organic framework (MOF) nanosheets as interlayers in TFC membranes (TFNi), using a polyethylene glycol (PEG) assisted exfoliation technique to mitigate issues of nanosheet restacking and aggregation. The uniformly distributed MOF interlayers significantly improved pure water permeance from 10.6 to 32.1 L m⁻² h⁻¹ bar⁻¹ while maintaining a high rejection of 97.0% towards Na₂SO₄. Moreover, the optimized membrane showed significant improvements in OMP removal, attributed to the increased negative charge and greater hydrophilicity of the polyamide rejection layer. These findings highlight the potential of 2D MOF nanosheets as interlayers in developing high-performance membranes for effective OMP removal and water reuse.<br></p>