Interfacially engineered carbon nanotube/PEDOT: PSS composite sponge for solar-driven water purification and dye removal for environmental sustainability

Abstract Considerable attention is given to conventional desalination methods for water purification. However, the widespread application of these methods is hindered by high operational costs, excessive energy consumption, and secondary environmental pollution. Accordingly, the development of energy-efficient and environmentally benign photothermal materials is critically important. In this work, three-dimensional (3D) macroporous composite foams composed of multiwalled carbon nanotubes (MWCNTs) and poly(3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT: PSS) were fabricated via freeze-drying. The resulting sponges achieve outstanding performance in terms of solar-driven interfacial water evaporation (SIWE), efficient adsorption of organic dyes, and robust anti-fouling properties. The light absorption capacity and surface hydrophilicity of these sponges can be precisely controlled by altering their chemical composition. The incorporation of MWCNTs and hydrophilic polyethylene oxide into the 3D sponge framework significantly improves the evaporation performance owing to improved broadband light absorption and facilitated water transport. Moreover, the MWCNT/PEDOT: PSS sponges have high adsorption capacities for methylene blue and methyl orange, enabling simultaneous desalination and contaminant removal. These results indicate that the interfacially engineered 3D MWCNT/PEDOT: PSS composite sponge is a suitable platform for efficient solar-driven water purification and sustainable environmental remediation.