Flexible Janus-like rGO Aerogel with Superelastic and Salt Resistance for Solar-Driven Desalination and Wastewater Purification

Abstract

Solar-driven interfacial evaporation (SDIE) offers a simple and affordable way to produce clean water, eliminating the need for complex infrastructure and fossil fuels. Aerogels are important in developing SDIE materials because of their three-dimensional network structure and low thermal conductivity. However, the complex preparation process and brittle mechanical properties of aerogels pose challenges for their future commercialization. In this work, we developed a flexible Janus-like reduced graphene oxide aerogel with superelasticity and salt resistance using a straightforward lyotropic plasticization foaming process. The hierarchical pore distribution within the ordered microstructure acts as an elastic buffer, dispersing external stress and allowing superelasticity under a 95% compression strain and a compressive stress of 0.948 MPa. The Janus-like graphene aerogel system demonstrated a water evaporation rate (WER) of 1.86 kg m^–2 h^–1 under 1 kW m² solar irradiation, with a photothermal conversion efficiency (PTCE) of 80.1%. This performance results from the combined effect of graphene’s broad light absorption and the surface structure of hydrophobically modified poly(dimethylsiloxane) (PDMS). In tests with 3.5 wt % NaCl solution for 8 h, the system maintained a stable evaporation rate above 1.76 kg m^–2 h^–1, while also achieving over 99.7% removal of organic dyes from wastewater and over 99.9% rejection of metal ions in seawater from the South China Sea. These findings highlight the potential of the PDMS/rGOA composite aerogel for practical solar-driven interfacial desalination and water purification.