Aquatic Plant-Inspired Floating Porous Materials for Sustainable Water Remediation*

The increased discharge of untreated wastewater poses significant risks to both aquatic ecosystems and human health. While conventional wastewater treatment methods effectively remove pollutants, they are often associated with high energy consumption and infrastructure demands. Photocatalytic remediation is a promising alternative due to the eco-friendly nature of photocatalysts and their ability to degrade various pollutants using solar energy. The efficiency of this process is determined by photocatalytic and mass transfer factors, including light absorption, interfacial interactions, and product removal. Aquatic plants have strong positive buoyancy, which maintains their position at the water-air interface, facilitating oxygen, nutrient, and light uptake, thereby enhancing water remediation under diverse environmental conditions. Here, inspired by aquatic plants, a photocatalytic water remediation system is developed by immobilizing TiO₂ on a porous PDMS substrate. This substrate, fabricated via a simple sacrificial template method, mimics the buoyancy mechanism of aquatic plants, resulting in enhanced floatability under both static and dynamic conditions. This aquatic plant-inspired water purifier (APWP) achieves a 97% degradation of methylene blue within 2 hours due to its improved light harvesting and mass transfer capabilities compared to non-biomimetic TiO₂/PDMS foams. The performance of the APWP highlights its potential for sustainable environmental remediation.