Bioinspired mesoporous hybrid materials based on bio-silica structures for efficient water collection under dry-wet cycles in karst area.

Karst regions face severe water scarcity due to rapid hydrological leakage and complex geological structures. To address this challenge, this study developed a bioinspired porous condensation material by integrating sand-based substrates with optimized hydrophilic-hydrophobic properties and aluminum fiber modifications. Through orthogonal experiments, the optimal formulation (0.3 mL 30 % HO, 3.4 mL water, 0.4 g foam stabilizer) achieved a high porosity of ∼58 % and uniform pore distribution (Féret diameter: 0.83 mm), enabling a water collection rate of 0.066-0.068 g g h. Aluminum fiber incorporation (≤4 g, ≤0.1 mm) enhanced thermal diffusivity by 37.5 %, facilitating rapid heat transfer for efficient vapor condensation. In simulated diurnal humidity-temperature cycles, the modified material exhibited dynamic water adsorption-desorption capabilities, with a 140 % improvement in nighttime water retention (0.06 g g) and 42.3 % higher daily yield compared to unmodified counterparts. The material's pore-thermal synergy, driven by threshold-controlled fiber networks, balanced capillary-driven water transport and heat-mediated condensation, overcoming structural instability under extreme temperature fluctuations. These results demonstrate a cost-effective strategy for designing environment-responsive water-harvesting materials, offering potential applications in arid regions, micro-irrigation systems, and humidity regulation.