Biomimetic Janus photothermal membrane for efficient interfacial solar evaporation and simultaneous water decontamination

Durable Antibacterial Photothermal Membrane Using Melanin-Inspired Cu-Doped Polynorepinephrine for Water Remediation

Solar-driven interfacial evaporation is an efficient approach to addressing water scarcity due to its environmental sustainability. However, the prolonged use of solar evaporators causes microbial contamination from wastewater. Inspired by the antifouling properties of polydopamine, we develop a series of mono- and dual-metal-loaded poly(norepinephrine) (PNE) nanoparticles by pre-doping multiple metal ions. Metal doping enhances the photothermal conversion efficiency (∼60%) of PNE by reducing the energy bandgap and imparts antimicrobial properties. Cu2+-loaded PNE (Cu-5) combined with laser achieves a 99.72% bactericidal rate against both E. coli and S. aureus. The Cu-5-coated cellulose membrane (Cu-5@CM) realized an evaporation rate of 2.21 kg m-2 h-1 under one sun with an evaporation efficiency of 97.4%. Cu-5@CM exhibits remarkable anti-biofouling properties, maintaining its surface integrity and evaporation performance even after 15 days of immersion in a bacterial environment. Its stable evaporation rate and long-lasting antimicrobial performance offer a promising solution to the biofouling challenges in seawater desalination.

Overview of Solar Steam Devices from Materials and Structures

The global shortage of freshwater supply has become an imminent problem. The high energy consumption of traditional desalination technology cannot meet the demand for sustainable energy development. Therefore, exploring new energy sources to obtain pure water has become one of the effective ways to solve the freshwater resource crisis. In recent years, solar steam technology which utilizes solar energy as the sole input source for photothermal conversion has shown to be sustainable, low-cost, and environmentally friendly, providing a viable low-carbon solution for freshwater supply. This review summarizes the latest developments in solar steam generators. The working principle of steam technology and the types of heating systems are described. The photothermal conversion mechanisms of different materials are illustrated. Emphasis is placed on describing strategies to optimize light absorption and improve steam efficiency from material properties to structural design. Finally, challenges in the development of solar steam devices are pointed out, aiming to provide new ideas for the development of solar steam devices and alleviate the shortage of freshwater resources.