Superhydrophobic composite coatings for photocatalysis and oil–water separation: durable and eco-friendly solutions for industrial applications

Synthesized DE@HTDMS-SiO₂ particles loaded with TiO₂ nanoparticles, linked to adhesive epoxy resin and the green hydrophobic agent cetyltrimethoxysilane, were utilized to fabricate superhydrophobic composite coatings on various substrates using a simple spraying technique. The resulting composite coating exhibited a contact angle of 156.6° and a rolling angle of 7.6°, demonstrating excellent self-cleaning properties, antifouling capabilities, and durability. The photocatalytic performance was evaluated by using visible light from a 220 W incandescent lamp as a light source. The results indicated that the composite coating could degrade both RhB and MB solutions by over 90%. In a custom-made oil–water separation device, the composite-coated cotton fabric achieved a separation efficiency exceeding 96% for mixtures of n-hexane and diesel. Even after 10 cycles of repeated separation, the efficiency remained above 89%. This underscores the composite coating’s remarkable photocatalytic performance and its capacity for efficient, recyclable oil–water separation. Furthermore, the hydrophobic angle of the composite superhydrophobic glass sheet decreased by only 2.3° after undergoing a three-month outdoor aging experiment. Additionally, the composite-coated cotton fabric maintained a certain level of hydrophobicity even after being submerged in a strong alkali solution for 24 h.