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 degrees. 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.