Superhydrophobic copper foams for use as marine water purification filters

This research addresses marine pollution, a critical environmental issue, by developing an innovative solution to overcome the limitations of traditional cleaning methods. Existing techniques are often inefficient due to their complexity, time-intensive processes, specialized personnel requirements, and high costs. This study explores a novel approach: the development of a superhydrophobic coating on copper foams as an efficient alternative for marine depollution.

Various efforts in creating hydrophobic porous materials, such as electrospinning and chemical vapor deposition, have faced challenges like high equipment costs, energy demands, and the use of harmful chemicals. In contrast, this study proposes a cost-effective and simplified method. A superhydrophobic coating was successfully fabricated on copper foams with varying levels of surface roughness through a two-step immersion process in silver nitrate and stearic acid solutions. Importantly, the substrate's surface roughness significantly influenced the growth of silver dendrites and the morphologies of stearic acid, resulting in distinct structural differences between rough and smooth copper foams. This process requires minimal chemicals, simple equipment, and fewer steps, making it a practical and sustainable option.

The hydrophobic coatings achieved exceptional contact angles of 180°, significantly higher than those reported in most studies. The coatings demonstrated remarkable thermal and chemical stability when subjected to different temperatures (100°C and -15°C) and immersion in water and NaCl, HCl, and NaOH solutions, even after a 40 h exposure. The separation efficiency remained consistently above 94% across various pollutants, demonstrating excellent stability and durability regardless of the substrate's surface roughness. The mechanical durability of the modified copper foams was evaluated through dragging tests and exposure to ultrasound, exhibiting promising results.

This study offers a transformative approach to marine depollution, presenting cost-effective and robust solutions that align with existing environmental strategies to protect and restore marine ecosystems.