Ultra-robust carbon fibers for multi-media purification via solar-evaporation

Abstract

Solar steam generation has been developed for purification of wastewater and seawater solely by virtue of sustainable solar energy. However, multi-media treatment, especially organic solvent purification, still remains challenging. Herein, the ultra-robust solar steam generator based on carbon fibers, modified by hydrothermal carbonization, is first fabricated for highly efficient purification of multi-media systems, including dyed organic solvent, oil-in-water emulsion and seawater. The modified carbon fibers show excellent mechanical strength (∼4.77 GPa), good wettability, improved surface area and excellent light absorption (∼93%) owing to the introduction of hierarchical carbon coating. The braiding fabrics can self-pump multi-media relying on the capillary forces among polar carbon fibers. Excellent production of clean water and organic solvent with high rejection of ions (<10 ppm salt ions), oil (∼11.9 ppm oil) and dye (∼99.99%) is demonstrated. After being corroded by dimethylacetamide (DMAc) and concentrated brine for 10 days, the tensile strength of carbon fiber filament is ultra-stable. The braiding carbon fiber fabrics can produce freshwater at a rate of 5.4 kg m⁻² per day from simulated Dead Seawater, enough to satisfy individual daily needs. Therefore, the carbon fiber-based materials have great application prospects for robust multi-media purification via highly efficient photothermal conversion.