Hierarchically porous bamboo fiber@ GO-SiO2 composite membrane for efficient oil/water emulsion separation

The discharge of oily wastewater posed severe threats to ecosystems and human health, underscoring the urgent need for sustainable and cost-effective membrane materials. In this study, a novel superhydrophilic and underwater superoleophobic BF@GO-SiO 2 membrane was constructed through a three-step process involving the delignification of bamboo powder, the blending of GO-SiO 2 hybrids for roughness enhancement, and subsequent vacuum filtration coupled with Polyethyleneimine (PEI) grafting to precisely modulate the pore structure and surface wettability. The resulting membrane exhibited a highly porous three-dimensional network structure, with surface roughness increasing proportionally to GO-SiO 2 content. Attributing to its cellulose-rich framework and robust hydration layer, the BF@GO-SiO 2 membrane achieved exceptional oil/water separation efficiency of 99.5% at high permeation fluxes of 535.2 L m −2 h −1 . Furthermore, the membrane demonstrated superior separation performance (up to 99.4%) for various oil-in-water emulsions, including surfactant-free and those stabilized by CTAB, Tween 80, and SDS. This outstanding performance was attributed to the synergistic effects of its excellent surface hydrophilicity, capillary forces and 3D water channels. The membrane also exhibited excellent durability, maintaining stable separation efficiency (above 98.0%) after 30 cycles and across a wide pH range. Furthermore, the composite membrane achieved a maximum tensile strength of 23.5 MPa, demonstrating its robust mechanical performance. This work provided a scalable strategy for fabricating high-performance separation membranes, offering significant potential for practical oily wastewater treatment applications. Graphical