Heterogeneous wettability composite sponge as a water treatment material integrating solar driven interface evaporation and PMS mediated organic degradation

In response to the dual challenges of global freshwater scarcity and organic pollutant control, this study innovatively developed a heterogeneous wettability composite sponge (HWCS) by integrating solar driven interfacial evaporation with peroxymonosulfate activation catalysis. The material features a heterogeneous wettability substrate formed by doping superhydrophobic SiO 2 aerogel particles into a superhydrophilic polyvinyl formal porous matrix. The SiO 2 aerogel particles reconstruct solution transport pathways by converting macroscale mass transfer channels into micro-nano multichannel networks, which can significantly suppress thermal conduction losses while ensuring the solution supply. After optimizing the aerogel particles doping amount (3 g per 30 g of 12 % PVA solution) and particle size (100 mesh), the evaporation efficiency of HWCS was enhanced from 1.088 kg·m −2 ·h −1 to 1.321 kg·m −2 ·h −1 , while the solar to vapor efficiency increased from 74.1 % to 90.2 % compared to homogeneous hydrophilic materials. Furthermore, the SDIE process synergistically enhanced PMS activation through localized temperature elevation and evaporation enrichment, achieving 91.6 % degradation of 100 ppm Congo Red within 90 min (apparent rate constant: 0.0289 min −1 ). HWCS also demonstrated robust mechanical strength, self-floating capability, and long-term stability, highlighting its potential for outdoor water treatment applications. This study offers a sustainable strategy to address both freshwater scarcity and organic pollution challenges.