SCGs-based heterogeneous aerogels for low-cost and efficient solar-driven desalination

Abstract

A novel double-layer aerogel is designed for solar-driven desalination which is derived from spent coffee grounds (SCGs). The top area of aerogel constructed by SCGs-based cellulose nanofiber (CNF) and activated carbon is the photothermal conversion layer (PCL) where the light is converted to heat and the water is transferred to steam. The bottom part established by CNF aerogel is the layer for water transportation. According to the results of desalination, the thickness of PCL has little impact on evaporation behavior. The evaporation rate of heterogeneous aerogel reaches to 2.577 kg·m⁻²·h⁻¹, and its average daily water yield can meet the requirement of drinking water for ten adults. Owing to the higher cost-effectiveness of evaporator (2.773 kg·h⁻¹·$⁻¹), it provides a promising strategy for the low-cost and efficient solar-driven desalination.