To overcome the surface instability of traditional polymeric membranes especially with superwetting behaviour, a robust superhydrophilic surface was fabricated with nano-TiO₂ inlaid on a hierarchical polylactide (PLA) ultrafiltration membrane via a spin coating process.

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.

To achieve highly efficient purification of emulsified oil, a superhydrophobic, superoleophilic and under-oil superhydrophobic poly(vinylidene fluoride) (PVDF) nanofibrous membrane was developed through a facile electrospinning strategy. The PVDF nanofibrous membrane exhibited a synchronous combination of nanofibers and micro/nanospheres, which was produced by solely controlling the PVDF concentration of the electrospun solutions. The fabricated PVDF nanofibrous membrane exhibited a water contact angle of 152° ± 2°, oil contact angle of 0° in air and under-oil–water contact angle of 152° ± 1° due to the inherently low surface energy and unique structures composed of nanofibers and micro/nanospheres. Thanks to the under-oil superhydrophobicity, hierarchical structure and high porosity (∼95%), the composite membrane showed extremely high permeability of 88 166 ± 652 L m⁻² h⁻¹ bar⁻¹ with separation efficiency higher than 99%, which was few orders of magnitude higher than the previous findings. Moreover, the nanofibrous membrane exhibited robust continuous separation, indicating its scalable application for purifying emulsified oil.