Anisotropic 3D Aerogel of Graphene Oxide and Poly(Vinyl Alcohol) for Desalination by Interfacial Solar Vapor Generation
Guanyu Zhao, Yue Zhang, Xuzhen Wang, Xingchen Ye, Shiqi Zhou, Wenyi Wang, Zongbin Zhao, Jieshan Qiu
Abstract
Interfacial solar vapor generation (ISVG) is a promising water treatment technology because it minimizes the carbon footprint and addresses water shortages. To further improve the solar energy efficiency in carbon material-based ISVG process, graphene oxide (GO) nanosheets and poly(vinyl alcohol) (PVA) are adopted as precursors for fabricating a three-dimensional aerogel (radial-GO/PVA) with anisotropic porous structure using an oriented freeze-casting technique. Experiments and numerical simulations reveal that benefiting from the horizontally radial struts and longitudinally lamellar struts with transversely parallel ligaments, radial-GO/PVA aerogel performs multifunctional features for ISVG, including excellent light absorption, rational water adjustment, good thermal management capability, and efficient salt rejection. A water evaporation rate of 1.58 kg·m –2 ·h –1 can be achieved under the standard solar irradiation (1 kW·m –2 ). More importantly, radial-GO/PVA aerogel exhibits a long-term stability for continuous water evaporation over 8 h in a concentrated 20 wt % NaCl solution, indicating the potential application for the desalination and purification of high concentration brine through ISVG route.