Figure 4.

iSTPV enabled water purification and solute recovery. a) Evaporation performance of the lab‐scale iSTPV at a high evaporation rate for 32 h. Inset, photographs showing the solute accumulation process. b) Photograph of the iSTPV used for outdoor test on the lawn at Nanjing University Xian Lin campus. Scale bar, 3.5 cm. c) Solar intensity, ambient temperature, and relative humidity of two sunny days during the evaluation of the evaporation performance of the iSTPV before and after solute accumulation over time from 6:00 a.m. to 6:00 p.m. d) Photograph of the iSTPV's surface before solute accumulation showing the 24 evaporation unit with the overall evaporation area of 15 cm × 25 cm. Scale bar, 3.5 cm. e) Photograph of the iSTPV showing solute (Ni²⁺) accumulation after water evaporation. Scale bar, 3.5 cm. f) The mass loss of water for the iSTPV before and after solute accumulation on the surface of the air‐laid paper during the outdoor test. g) PH of the solution before and after purification. h) Water purification performance of the iSTPV compared with several competitive purification techniques.