Silver nanoparticles-polydopamine-wax gourd: An antimicrobial solar evaporator with enhanced steam generation

Solar-driven interfacial evaporation is an emerging environmentally-friendly technology to produce freshwater, but the current interface evaporators are restricted by their high cost, complex fabrication processes, and low resistance to environmental conditions. Here, a low-cost and high-efficient evaporator was prepared simply by modifying natural wax gourd with polydopamine (PDA) and silver nanoparticles (AgNPs). The prepared AgNPs-PDA-wax gourd exhibited excellent light absorption (>94%) in the whole solar spectrum (300-2500 nm). Under 1 sun illumination, the prepared evaporator achieved an extraordinary evaporation rate of 1.70 kg m(-2) h(-1) (efficiency of 83.21%), which was 3.78 and 1.21 times higher than the rates of natural wax gourd and PDA-wax gourd, respectively. Such excellent performance was mainly attributed to the synergic light-to-heat conversion capability between localized surface plasmon resonance effect from AgNPs and enhanced light-adsorption ability from PDA. Due to the presence of AgNPs, the final evaporator also displayed a fascinating antibacterial behavior for both E. coli and S. aureus even during evaporating actual lake water. Meanwhile, the AgNPs-PDA-wax gourd presented good durability during 10-cycled experiments, seawater desalination, dye water purification and some extreme conditions (acid, alkaline and freezing). These results suggested the great potential for future practical applications of such biomass solar evaporators.

Automated summary

Researchers have developed a low-cost and high-efficiency solar evaporator by modifying natural wax gourd with polydopamine and silver nanoparticles. The prepared evaporator showed excellent light absorption and high evaporation rate, as well as antibacterial behavior and durability. This biomass solar evaporator holds great potential for practical applications.