Facile fabrication of electrospinning cellulose acetate/graphene composite nanofiber membrane with high solar-to-thermal conversion and oil resistance performance for efficient solar-driven water evaporation

Solar-driven water evaporation is a promising approach to solve the issue of water resource shortage. Herein, a cellulose acetate (CA)/graphene(G) nanofiber membrane evaporator with superior oil resistance was prepared by electrospinning and subsequently with the deacetylation process. The as-fabricated d-CA/G composite nanofiber membranes possess high solar absorption, high porosity, and low thermal conductivity. The evaporation rate of d-CA/G composite nanofiber membrane with a graphene concentration of 3 % for pure water can reach 1.38 kg m−2 h−1 with the corresponding efficiency of 88.4 % under one sun illumination. Moreover, the d-CA/G composite nanofiber membrane possesses super hydrophilic and underwater superoleophobicity. Thus, the d-CA/G composite nanofiber membrane can resist fouling by oils and dissolve the concentrated salt back into bulk water, resulting in efficient purification capacity for oil-in-water emulsion and stable desalination performance for seawater in the long term. The evaporation rate of the d-CA/G evaporator can approach 1.37 kg m−2 h−1 when used for the purification of oil-in-water emulsion. This study provides a facile way for the development of multifunctional nanofiber membrane evaporators with highly efficient and sustainable for seawater desalination and wastewater treatment.