A high-efficiency, salt-resistant, MXene/diatomite-modified coconut husk-based evaporator for solar steam generation

Solar-driven desalination has received considerable attention as a promising approach to alleviate water scarcity due to its environmental friendliness and energy efficiency. In this study, an efficient biomass-based evaporator was developed through coordinating diatomite and titanium carbide MXene (Ti3C2Tx) on delignified coconut husk. Owing to the numerous hydroxyl and carboxyl groups present on the surfaces of diatomite, MXene, and the cellulose in coconut husks, the introduction of these additional hydrophilic groups stimulated water activation, thereby increasing the proportion of intermediate water. The excellent structural design and constituent materials of the evaporator contributed to reducing the evaporation enthalpy of water by approximately 18%. In addition, the obtained evaporator was light weight, remarkably strong, and exhibited an excellent light absorption capacity (~91.48%), low thermal conductivity (0.04716 W m−1 K−1), and low evaporation enthalpy (~1854 J g−1). The resultant evaporator delivered a water evaporation rate of 2.1 kg m−2 h−1 and a photothermal conversion efficiency of 90.64% under 1 sun exposure. The evaporator exhibited remarkable durability, salt resistance, metal ion adsorption, and dye removal properties. Therefore, this study provides a novel approach to realize the high-value utilization of waste coconut husks that is promising for solar steam generation applications.