3D Printed Sandpile-Shaped Photothermal Evaporator Based on Thiol-Ene Click Chemistry for Efficient Water Evaporation

The interface evaporation technology driven by solar energy has received widespread attention due to its advantages of being clean, pollution-free, and low in energy consumption. However, the cumbersome preparation process of existing high-efficiency evaporators hinders their large-scale promotion and application. Furthermore, we find that the inclined slope of the sandpile has the geometric condition of "forced reflection," and the incident light can form reciprocating reflection between adjacent sandpiles, greatly improving the light capture efficiency and providing a structural basis for achieving efficient evaporation. Inspired by this, we construct a sandpile-shaped photothermal evaporator with different array densities by digital light processing (DLP) 3D printing technology with thiol-ene click chemistry reactions, using pentaerythritol tetrakis(3-mercaptopropionate) (PETMP) and poly(ethylene glycol) diacrylate (PEGDA) and molybdenum disulfide (MoS2) as photothermal materials to achieve integrated molding of the evaporator. Through structural optimization, the 3 × 3 array structure exhibits the best evaporation performance, with an evaporation rate of 1.91 kg m-2 h-1 and an evaporation efficiency of 90.9% at one solar intensity. When used for photocatalytic degradation of dye wastewater, the degradation efficiency of dyes can reach 86%. In addition, using a 3 × 3 array evaporator to treat salt-containing dye wastewater can cause directional salt collection due to the temperature difference between the top and bottom. After 5 complete evaporation and collection cycles, the average salt collection capacity of the evaporator can still be maintained at 0.593 g, with a salt collection rate of 158.34 mg m-2 h-1. This biomimetic photothermal evaporator provides a solution for the recycle and high purification of salt-containing dye wastewater.