Synthesis and sustainable application of fluorosilicon-based superhydrophobic coatings for high-salt wastewater treatment: A short two-step method

A fluorosilicon-based superhydrophobic coating (ER-SiO2/PVDF/SFT) was engineered by a novel non-hydrolytic two-step methodology, demonstrating exceptional fouling resistance in hypersaline wastewater treatment. The coating achieved a water contact angle of 154.3 ± 0.5◦, representing a 12 % increase over epoxy resin (ER) reference coatings – and effectively repelled organic contaminants (ethylene glycol contact angle: 148.8 ± 1.8◦). Antifouling efficiency reached 70 % against CaCO3 fouling deposits in simulated two kinds of high-salt fouling solution, attributable to ultralow surface energy and biomimetic hierarchical roughness. Long-term thermal fouling tests revealed <5 % hydrophobicity decay, which would save energy in thermal evaporation. The short two-step method not only prevents fouling with minimal operational complexity but also facilitates easy reapplication, reducing material waste and chemical usage while supporting a circular economy in industrial water reuse. This scalable, low-waste coating supports Zero Liquid Discharge (ZLD) initiatives and UN Sustainable Development Goals 6 and 12, making it ideal for industrial applications and sustainable resource consumption.