Electrically Conductive Carbon Aerogels with High Salt-Resistance for Efficient Solar-Driven Interfacial Evaporation.

Solar-driven interfacial evaporation (SIE) is a promising approach for obtaining clean water but suffers from serious salt-fouling and poor long-term performance in seawater. Here, we report a high-performance salt-resistant SIE system from the perspective of nature sustainability. An electrically conductive and magnetic carbon aerogel is prepared by carbonization of Fe3O4-modified cellulose that originated from waste paper, and then its external surface is activated using O2-plasma, forming the Janus superhydrophilic/superhydrophobic structure. The superhydrophilic external surface of the aerogel with macroporous skeleton assures ultrafast and adequate water supply and salt diffusion, while the superhydrophobic interior is the thermal insulator hindering water/salt infiltration. Benefiting from high solar absorption (∼97%), low thermal conductivity, unique Janus structure, and photothermal/electrothermal effects, the aerogel shows high evaporation rate (2.1 kg m-2 h-1, 1 sun) for simulated seawater. The aerogel features the following remarkable long-term salt-antifouling performance: (i) >20 d continuous evaporation in simulated seawater without degradation, even in 10 wt % NaCl solution, and (ii) >50 h continuous evaporation without seawater replenishment. Moreover, heavy metal ions, soluble organics, and oil can be completely removed from complex wastewater by the aerogel. This study offers an alternative approach in achieving clean water via SIE of seawater and complex wastewater.