A polydopamine-modified rattan porous solar evaporator with high evaporation performance achieving salt-crystallization resistance and environmentally adaptive water purification

Salt crystallization at evaporation interfaces severely limits the efficiency and durability of solar-driven desalination systems, hindering their practical application. Here, we employed alkali-treated and dried rattan waste to construct a solar evaporator with a hierarchically porous substrate, and further incorporated poly-dopamine (PDA) to prepare the PDA-modified rattan evaporator (PDA-AR), achieving synergistically enhanced evaporation efficiency and long-term salt resistance. PDA-AR features contracted macroscopic pores (100–200 μm) and a dense framework, which increases the effective evaporation area. In a 20 wt% salt solution, PDA-AR exhibits a high evaporation rate (1.47 kg·m^− 2·h^− 1) and high photothermal efficiency (90.4%). And it maintains stable salt resistance for 30 consecutive cycles. Mechanistic studies reveal that PDA-AR enhances capillary forces and hydrogen bonding through pore contraction, thereby improving water transport capability and compressive strength via rapid salt dissolution. Furthermore, PDA-AR exhibits strong environmental adaptability, effectively purifying dye-contaminated water, as confirmed by UV–vis absorption spectra showing removal of methylene blue (~ 291 and ~ 664 nm) and methyl orange (~ 273 and ~ 465 nm). This work highlights microstructure regulation as a viable strategy to optimize solar evaporators, offering scalable solutions for sustainable desalination and water purification.