%0 Journal Article
%A Akanksha K Menon
%A Iwan Haechler
%A Sumanjeet Kaur
%A Sean D Lubner
%A Ravi S Prasher
%B Nature Sustainability
%D 2020
%G eng
%N 2
%P 144 - 151
%R 10.1038/s41893-019-0445-5
%T Enhanced solar evaporation using a photo-thermal umbrella for wastewater management
%V 3
%8 01/2020
%! Nat Sustain
%X <p><span>Zero-liquid discharge is an emerging wastewater management strategy that maximizes water recovery for reuse and produces a solid waste, thereby lowering the environmental impact of wastewater disposal. Evaporation ponds harvest solar energy as heat for zero-liquid discharge, but require large land areas due to low evaporation rates. Here, we demonstrate a passive and non-contact approach to enhance evaporation by more than 100% using a photo-thermal device that converts sunlight into mid-infrared radiation where water is strongly absorbing. As a result, heat is localized at the water’s surface through radiative coupling, resulting in better utilization of solar energy with a conversion efficiency of 43%. The non-contact nature of the device makes it uniquely suited to treat a wide range of wastewater without contamination, and the use of commercial materials enables a potentially low-cost and highly scalable technology for sustainable wastewater management, with the added benefit of salt recovery.</span></p>