A Water-Efficient Artificial Phytoextraction Technology for the Remediation of Cesium-Contaminated Soil Inspired by Plant Transpiration and the Hydrologic Cycle

Cesium ions (Cs⁺) are notable radioactive contaminants hazardous to humans and the environment. Among various remediation methods, adsorption is a practical way to remove Cs⁺ from water, and Prussian blue (PB) is well-known as an efficient Cs⁺ adsorbent. Although various PB derivatives have been proposed to treat Cs⁺-contaminated water, soil remediation is still challenging due to the limited mobility of pollutants in soil. Here, we proposed a water-efficient artificial phytoextraction system integrated with a plant-like interfacial solar vapor generation (ISVG) device for remediation of Cs⁺-contaminated soil. The leaf of the device consisting of PB immobilized on cellulose nanofiber (CNF-PB) endows the device with the abilities of accumulation of Cs⁺ as well as solar-to-thermal conversion for water evaporation. The proposed remediation system showed significant Cs⁺ removal ability from contaminated agricultural soil under actual sunlight, with no additional water required due to the system's water-recycling capability. The device can be readily revived by replacing the Cs⁺ accumulated leaf with a new one, and the used adsorbent can be easily regenerated by acid washing for reuse. Thus, the proposed system is a sustainable, fast, and eco-friendly soil remediation strategy for Cs⁺ contamination.