Escalator-Inspired Self-Cycling Solar Evaporator with Synergistic Salt Resistance and Thermal Management

The solar-driven interface evaporation (SIE) technology presents a green and sustainable solution to the growing challenges of water resource scarcity. However, the salt crystallization and the thermal management are significant obstacles for the practical application of SIE. Herein, inspired by the transportation system of the escalator, a three-dimensional (3D) self-cycling evaporator (CDs-LR) with synergistic salt resistance and thermal management was fabricated by combining carbon dots (CDs) with the loofah rag (LR). The unique hydrophilicity, fibrous structure, and solar absorption properties allows the CDs-LR to achieve an exceptional evaporation rate of 5.21 kg·m^-2·h^-1. More importantly, photovoltaic panels, a charge controller, and a rechargeable battery were integrated with CDs-LR to design a self-cycling device. During the daytime, the device efficiently evaporates water while storing electricity generated by photovoltaic panels in the battery. At night, the stored electrical energy powers the evaporator, enabling automatic salt removal and redissolution. The results of the 400 h evaporation experiment in a 10 wt.% sodium chloride (NaCl) solution and the COMSOL simulation of salt ion concentration confirm its outstanding salt resistance. Furthermore, experimental results indicate that CDs-LR exhibits excellent wastewater purification and antibacterial capabilities, making it a promising solution to the global water shortage problem.