SCG-Based CNF Aerogels with Oriented and Aligned Porous Structure for Solar Interfacial Desalination.

Spent coffee grounds are recognized as a green and sustainable resource of cellulose nanofiber (CNF), which can further form aerogels with rGO for solar-driven interfacial desalination via directional freezing technology. The vertically arranged channels provide better photothermal conversion performance and salt tolerance of rGO/CNF aerogels. Their max evaporation rate can reach to 2.729 kg·m-2·h-1 under natural sunlight. In terms of long-term application (10 days), the aerogels exhibit a stable evaporation property in outdoor environments. The optimum daily average water yield is 15.00 L·m-2, which can fulfill the daily water requirement of six people.