All-in-one wood-based evaporator for enhanced solar-driven interfacial evaporation and photocatalytic antibiotic degradation.

Abstract

Solar-driven interfacial evaporation is regarded as an ideal solution for alleviating the global freshwater shortage. However, evaporation alone is insufficient to address the increasingly severe challenge of water pollution. Herein, an all-in-one wood-based evaporator (BCN@SCDBW) was successfully fabricated by integrating interfacial evaporation and photocatalytic degradation functions onto wood, using delignified balsa wood as a substrate, through surface carbonization and ultrasonic-assisted deposition of black graphitic carbon nitride (BCN). BCN@SCDBW exhibited a light absorption up to 88.3% across the entire wavelength range, with its evaporation rate of 2.21 kg m^-2 h^-1 under one sun irradiation. BCN@SCDBW exhibited a vaporization enthalpy as low as 1422 J g^-1, which stemmed from noncovalent interactions between hydrophilic groups and water molecules, significantly increased the proportion of intermediate water. Moreover, BCN@SCDBW demonstrated outstanding salt-resistance in 15 wt% NaCl solution, and freshwater produced by evaporation from seawater met WHO and EPA standards, and achieved effective purification of various wastewater. More importantly, BCN@SCDBW successfully suppressed the recombination of photo-generated carriers produced from BCN, thereby significantly enhancing the photocatalytic degradation performance. This resulted in a 91% degradation efficiency of tetracycline within 60 min, with ·OH and ·O₂^- identified as the main radicals involved in photocatalytic degradation process. This work provides a new concept for developing multifunctional wood-based solar-driven interfacial evaporators.