Superhydrophobic copper foam modified with hierarchical stearic acid/CuSiO3/Cu(OH)2 nanocomposites for efficient water/oil separation

Developing efficient, durable and affordable oil-water separation technologies is critical to address the challenges of oily wastewater treatment. In this work, a microsphere-like CuSiO3 embedded Cu(OH)2 nanowires array was prepared on copper foam (CF) support (defined as CF/Cu(OH)2/CuSiO3) by using a simple chemical etching and hydrothermal method. After modifying with stearic acid (SA), such a novel CF/Cu(OH)2/CuSiO3-SA membrane presented excellent superhydrophobicity with a static water contact angle of 155.6°. The ammonia concentration in the precursor solution and the hydrothermal reaction time were critical for the morphology and the associated hydrophobicity of the CF/Cu(OH)2/CuSiO3-SA membrane. The as-prepared superhydrophobic CF had efficient anti-corrosion and mechanical properties and demonstrated an excellent separation capability of oil-water mixtures with a separation efficiency of 98.4%. It also exhibited a good separation efficiency of 98.3% for various water-in-oil emulsions, and delivered an outstanding separation efficiency of 98.2% towards oil/water mixture after operating successive 30 cycles of oil-water separation. With the inherent advantages of high separation efficiency of oil/water emulsion, good physicochemical stability and durability, and high mechanical and corrosion resistance, the novel CF/Cu(OH)2/CuSiO3-SA membrane is potentially useful in practical applications for oily wastewater treatment.