A Floating Integrated Solar Micro-Evaporator for Self-Cleaning Desalination and Organic Degradation

Safe and clean freshwater harvesting from (organic-containing) saline or wastewater holds great potential for mitigating water scarcity and pollution, but remains challenging. Herein, a floating photothermal/catalytic-integrated interfacial micro-evaporator (g-C3N4@PANI/PS) is reported as a proof-of-concept multifunctional scavenger evaporator system (MSES) to achieve both solar-driven complete desalination and organic degradation. The spherical porous lightweight polystyrene core, incorporated with a black surface functional layer (g-C3N4@PANI), enables the hybrid micro-evaporator to naturally float and thereby collectively self-assemble under surface tension for interfacial evaporation, which achieves preeminent self-cleaning for complete salt/solute separation and efficient organic photodegradation under rotation. Remarkably, the floating micro-evaporator achieves a high solar-vapor conversion efficiency of approximate to 90% with high interfacial energy localization and provides abundant active photocatalytic sites on the interface, which is further enhanced by interfacial photothermal cooperation. High photo-driven degradation efficiencies of 99% for nonvolatile organic compounds (non-VOC) bisphenol A and 95% for VOC phenol in wastewater are achieved. An outdoor comprehensive solar water treatment test toward organic-containing high-salinity sewage verifies the feasibility of MSES for sustainable freshwater harvesting (1.3 kg m(-2) h(-1)), downstream salt recovery, and organic degradation. This strategy may inspire an integrated solution of water scarcity, clean energy, and environmental pollution toward carbon neutrality.

Automated summary

A floating photothermal/catalytic-integrated interfacial micro-evaporator is developed for solar-driven desalination and organic degradation, achieving high conversion efficiency and efficient removal of pollutants.