# A Robust Solar Evaporator with Hierarchical Architecture for Ultrahigh Efficiency and Large‐Scale Zero‐Liquid‐Discharge Desalination

## TL;DR

A new solar-powered desalination system uses a mycelium-based design to efficiently produce freshwater from high-salinity brine.

## Contribution

A mycelium-derived hierarchical evaporator that achieves ultrahigh efficiency and zero liquid discharge in desalination.

## Key findings

- The evaporator achieves an evaporation rate of up to 10.25 kg m−2 h−1 for 25 wt.% brine.
- It enables efficient salt collection and zero liquid discharge over 145 hours in high-salinity brine.
- A scaled-up system produces 6 kg m−2 h−1 of freshwater outdoors and supports self-sustainable agricultural irrigation.

## Abstract

Solar‐driven desalination offers a green and sustainable strategy for solving the issue of freshwater scarcity. However, it remains a challenge to develop a robust evaporator via an eco‐friendly strategy, capable of resolving the long‐standing trade‐off between the water supply, salt accumulation, and thermal localization. Herein, a hierarchical solar‐absorbing architecture derived from mycelium is developed for high‐performance desalination. With the merits of multi‐level spatially low‐tortuosity channels, gradient wettability and directional transport, the evaporator achieves an impressive evaporation rate (up to 10.25 kg m−2 h−1 for 25 wt.% brine), efficient salt collection (1.95 kg m−2 h−1 for 25 wt.% brine), zero liquid discharge desalination, and long‐term stability (over 145 h in 10–25 wt.% brine). Moreover, the scaled‐up desalination system exhibits an ultrahigh freshwater production rate of 6 kg m−2 h−1 and a daily freshwater yield of up to 32 L m−2 during the outdoor desalination test. A continuous desalination‐cultivation platform demonstrates the feasibility of the evaporator for self‐sustainable agricultural irrigation. This low‐cost, mycelium‐based hierarchical architecture opens an avenue to advance green and sustainable strategy for highly efficient and large‐scale desalination of high‐salinity brine.

This study presents a low‐carbon footprint, robust 3D (three‐dimensional) evaporator featuring multi‐level low‐tortuosity channels for highly efficient desalination. It achieves an outstanding average evaporation rate of 8.1 kg m−2 h−1, salt collection rate of 1.95 kg m−2 h−1, and durability in high‐salinity brine. It also exhibits excellent outdoor water production rate, enabling a self‐sustainable agricultural irrigation for crop growth.