Enhanced interfacial evaporation of CF@NC fabric via coupled photo-thermal and Joule-heating effect

To address the challenges of global water pollution and scarcity, solar-driven interfacial water evaporation has emerged as a viable method for producing clean water. Nevertheless, the efficacy of most extant interfacial evaporation systems were contingent upon abundant sunlight, thereby constraining their utility. To surmount the limitation, this study introduced a coupled tunable photo-thermal and Joule-heating process for interfacial evaporation utilizing carbon fiber (CF) modified by N-doped carbon nanotubes (NC). The CF@NC had highly graphitized structure, excellent light-absorbing ability and hydrophilicity, which made it suitable for photo-thermal and Joule-heating conversion. Under the coupled effect of photo-thermal and Joule-heating, the evaporation rate reached 10.37 kg·m−2·h−1 with 1 sun and 2.5 V, while the rate was 1.81 kg·m−2·h−1 under only 1 sun and 7.63 kg·m−2·h−1 with 2.5 V. Meanwhile, the CF@NC fabric evaporator also showed promising potential in salt tolerance and dye wastewater treatment. Under continuous all-day operation, a superior purification performance was achieved, which realized long periods of no salt operation and effectively remove the Rhodamine B and methyl orange in the water. Considering the high evaporation rate and reliable water yields obtained from simulated seawater and dye wastewater, the CF@NC fabric evaporator hold great promise for highly efficient purification.