Enhanced condensation of photoelectrothermally heated vapors using a superhydrophilic surface

Water scarcity is a pressing global challenge, exacerbated by environmental pollution and population growth. Conventional methods of freshwater production from seawater and wastewater are often inefficient, costly, and carbon intensive. The present study is aimed to enhance condensation of vapors generated from a photo-electrothermal (PhET) evaporation system by using a superhydrophilic surface-a method that has not been extensively studied to date. The desalination evaporation system utilizes a combination of solar light and thermal energies to heat seawater, and evaporated vapors are condensed to yield potable freshwater. A thin film composed of polyethylene glycol (PEG), 3-aminopropyltriethoxysilane (KH550), and tetraethyl orthosilicate (TEOS) is deposited onto a glass substrate via spin coating and then cured at 245°C to form a superhydrophilic surface. To confirm successful formation of the hybrid PEG-KH550-TEOS superwettable film, the surface morphology and chemical composition of the surface are analyzed by using scanning electron microscopy (SEM) and Raman spectroscopy. The chemical and mechanical stabilities of the superhydrophilic surface are examined for various corrosive solutions through adhesive tape peel-off tests. The retention of superhydrophilicity under harsh conditions demonstrates the material's suitability and durability of the developed surface in outdoor applications. Surface wettability, vapor condensation efficiency, water collection rate, and wetting stability are systematically investigated. As a result, the proposed hybrid superwettable surface enhances vapor condensation and water collection significantly. Best performance occurs at a tilting angle of the substrate 45°, under 1 sun solar irradiation and 3.5V input voltage. The coated glass surface exhibits excellent vapor condensation performance in outdoor conditions without any additional heating or cooling, outperforming conventional uncoated glass surfaces. Based on these findings, the fabricated superhydrophilic surface offers highly efficient condensation of vapors generated by photoelectrothermal evaporations. Overall, the proposed surface would be utilized as a sustainable solution for effective condensation of steamed vapors in seawater desalination applications.