Upcycled graphene nanoplatelets integrated fiber-based Janus membranes for enhanced solar-driven interfacial steam generation†

The increasing demand for drinking water and environmental concerns related to fossil fuels have given rise to the use of solar energy in water desalination. Solar-driven interfacial steam generation is a promising method for water purification, particularly in remote areas. Janus membranes, featuring bilayer hydrophobic/hydrophilic structures, offer high functionality and have attracted significant interest in this field. This study explores the integration of novel graphene nanoplatelets (GNP) derived from waste tire pyrolysis through upcycling as a photothermal source in Janus membranes. The membranes consist of polyacrylonitrile (PAN) nanofibrous membranes for water supply and polymethyl methacrylate (PMMA)/graphene nanoplatelets (GNP) nanofibrous membranes for light harvesting. The effects of GNP content and layer thicknesses on photothermal activity, water transport, and overall evaporation rate were analyzed experimentally and numerically. The results showed that a decrease in membrane thickness led to a 19% to 63% enhancement in evaporation rate, highlighting the importance of optimizing membrane design for efficient water desalination.