Fabrication and Performance of a SiO<sub>2</sub>/CMC-Fe<sup>3+</sup>-Coated Copper Mesh for Efficient Oil-Water Separation.

Abstract

Oil-water separation remains a critical environmental challenge for treating industrial effluents and marine oil spills. This study presents a novel SiO₂/CMC-Fe³⁺ (SCF) composite mesh fabricated through an environmentally friendly two-step approach: hydrophilic silicon dioxide (SiO₂) nanoparticle deposition on copper mesh, followed by CMC-Fe³⁺ hydrogel surface modification. The synergistic interactions among SiO₂ nanoparticles, CMC-Fe³⁺ hydrogel, and copper substrate through hydrogen bonding and metal chelation create a hierarchical structure, exhibiting superhydrophilicity and underwater superoleophobicity. Under gravity-driven conditions, the SCF mesh achieves high performance with >99% separation efficiency and up to 4.019 × 10⁴ L·m^-2·h^-1 water flux across diverse oil types. The mesh demonstrates excellent durability, maintaining >99.5% efficiency after 60 cycles and exhibiting stability under harsh conditions, including extreme pH, high salinity, and temperature variations, with separation efficiencies above 98% after extended testing. The combination of high performance, enhanced stability, cost-effectiveness, and environmental compatibility positions the SCF mesh as a promising solution for offshore oil spill management, underwater oil treatment, and industrial oily wastewater purification.