Enhancing the photocatalytic membranes performance via lignin sacrificial modification

Membrane separation technology can efficiently separate contaminants to achieve wastewater resource recovery and purification. Although photocatalytic membranes offer an effective route for self-cleaning, the highly reactive radicals generated during photocatalysis inevitably attack and degrade polymer substrates, compromising long-term stability. To address this limitation, the natural lignin was coordinated into photocatalytic membranes, serving dual functional roles. First, lignin as a sacrificial agent preferentially reacts with reactive oxygen species, thereby effectively protecting the polymer chains from oxidative damage. Second, under UV irradiation, part of the lignin undergoes controlled degradation, during which its aromatic ring structures are cleaved and hydrophilic oxygen-containing functional groups are generated in situ. This process simultaneously enhances surface hydrophilicity and increasing porosity. The optimized membrane exhibited a BSA solution filtration flux of 53.3 L·m −2 ·h −1 and rejection of 97.1%. After UV irradiation, the membrane demonstrated a substantially enhanced pure water flux, stabilizing at 157.9 L·m −2 ·h −1 . Furthermore, during long-term cyclic separation tests with landfill leachate, the membrane achieved a flux recovery ratio over 100%. This work not only provides a novel strategy for mitigating membrane fouling, but also opens a new pathway for the high-value utilization of biomass resources.