Cost-effective, highly efficient, and stable evaporator constructed of Chinese ink impregnation superhydrophobic Xuan paper for solar-driven interfacial organic solvent purification

The lack of cost-effective, highly efficient, and stable photothermal conversion materials in organic solvents greatly hinders the development of solar-driven interfacial evaporation for organic solvent purification. Herein, inspired by the traditional Chinese calligraphy culture, black ink impregnated superhydrophobic Xuan paper membrane (XPBI) is fabricated via a pressing-impregnation method for solar-driven interfacial organic solvent purification. The high photothermal conversion efficiency and long-term stability of XPBI are attributed to the inherent stability, superhydrophobic surface, and abundant channels of Xuan paper, as well as strong adhesion with carbon black particles. As a result, XPBI exhibited a high light absorption of 94.96 % within a broadband wavelength. The evaporation rates of DMF and NMP for XPBI under one sun were 3.63 and 1.44 kg·m−2·h−1, 49 and 127 times higher than that of natural evaporation. After natural sunlight irradiation for 8 h, XPBI evaporated 37.58 and 9.63 kg·m−2 IPA and DMF with organic dye rejection rates of 99.7 %. Furthermore, the simulation and optimization of cotton bud arrangement for organic solvent transport is proven to inhibit the membrane pollution of dye molecules for XPBI. This work demonstrates a low-cost, highly efficient, and stable photothermal membrane evaporator as an energy-saving and low-carbon technical prototype for organic solvent purification.