Anisotropic Evaporator with a T‐Shape Design for High‐Performance Solar‐Driven Zero‐Liquid Discharge

Abstract Solar‐driven evaporation is regarded as a sustainable wastewater treatment strategy for clean water recovery and salt condensation. However, achieving both high evaporation rate and long‐term stability remain challenging due to poor thermal management and rapid salt accumulation and blocking. Here, a T‐shape solar‐driven evaporator, composed of a surface‐carbonized longitudinal wood membrane (C‐L‐wood) is demonstrated as the top “” for solar harvesting/vapor generation/salt collection and another piece of natural L‐wood as the support “  ” for brine transporting and thermally insulating. The horizontally aligned micro‐channels of C‐L‐wood have a low perpendicular thermal conductivity and can effectively localize the thermal energy for rapid evaporation. Meanwhile, the brine is guided to transport from the support L‐wood (“  ”) to the centerline of the top evaporator and then toward the double edge (“”), during which clean water is evaporated and salt is crystallized at the edge. The T‐shape evaporator demonstrates a high evaporation rate of 2.43 kg m −2 h −1 under 1 sun irradiation, and is stable for 7 days of the outdoor operation, which simultaneously realizes clean water evaporation and salt collection (including Cu 2+ , CrO 4 2− , Co 2+ ), and achieves zero‐liquid discharge. Therefore, the T‐shape design provides an effective strategy for high performance wastewater treatment.