A research team at the Daegu Gyeongbuk Institute of Science and Technology (DGIST), spearheaded by Professor Seongkyun Kim from the Department of Physics and Chemistry, has unveiled a groundbreaking solar-powered artificial plant device capable of purifying soil contaminated with radioactive cesium. This innovation harnesses the principles of plant transpiration—a natural process where plants absorb water through their roots and release it as vapor through their leaves—but unlike natural flora, this device operates entirely on sunlight without the need for external electricity or supplementary water. By mimicking plant behavior, it collects cesium ions selectively in its artificial leaves, offering a rapid and efficient method for decontaminating soil on-site.
Radioactive cesium, denoted chemically as Cs⁺, poses a daunting environmental challenge worldwide. Its long half-life results in persistent contamination, and its high water solubility facilitates extensive dispersion through ecosystems. This radioactive element, when absorbed by living organisms, accumulates predominantly in muscle and bone tissues, where it poses serious health hazards including cancer and organ damage. The urgency of addressing cesium contamination was underscored following the 2011 Fukushima nuclear disaster when Japanese agricultural and seafood products were halted in trade due to surpassing safe cesium thresholds. Despite advances in purifying contaminated water via specialized adsorbents, soil remediation remains significantly more complex due to the lack of effective, scalable technologies to treat contaminated earth without excavation.
Phytoremediation, the biological approach employing live plants to remediate polluted soils, has long been considered a promising path for dealing with radionuclide contamination. This strategy relies on plants’ natural ability to uptake pollutants through their root systems and sequester them in shoots or leaves. However, phytoremediation is hampered by several intrinsic limitations: the slow growth rates of plants, the limited bioaccumulation capacity, seasonal and climatic dependencies, and the time-intensive nature of the process. Moreover, the harvested plants become radioactive waste themselves, necessitating careful handling and additional remediation steps. These factors have restricted the practical implementation of phytoremediation for critical contamination scenarios requiring rapid and effective intervention.
To circumvent these challenges, Professor Kim’s laboratory has engineered an artificial transpiration system designed to accelerate the purification of soils laced with radioactive cesium. By employing specially designed materials that imitate the selective ion absorption properties of plant roots and leaves, the device actively extracts Cs⁺ from contaminated soil water. Solar energy powers the evaporation of pure water, which is then cycled back to the soil through a closed-loop recovery mechanism, effectively creating a water-neutral remediation cycle. This ingenious closed system eliminates the need for external water addition, reducing resource consumption and enhancing feasibility for remote or resource-limited sites.
One of the most striking advantages of this device lies in its reusability and cost-effectiveness. The artificial leaves act as cesium reservoirs, capturing the radioactive ions while allowing vaporized water to escape. Once saturated, the leaves can be replaced, enabling continuous remediation cycles. The spent leaves, rich in cesium, can be treated with acidic solutions to desorb the radioactive ions, thereby regenerating the adsorbent material for reuse. This process not only minimizes waste generation but also offers economic and environmental benefits by reducing the demand for fresh adsorbent compounds and lowering operational burdens.
Experimentation with soils artificially contaminated with various cesium concentrations has demonstrated the device’s exceptional efficiency. Within a mere 20 days, cesium concentrations in treated soils dropped by over 95%, a process that conventionally requires months under natural phytoremediation conditions. This marked acceleration results from the device’s optimized ion-selective absorption and rapid water evaporation cycles, enabled solely by sunlight. The implications are profound, offering a scalable solution that can be deployed at contaminated agricultural sites and nuclear accident zones, ensuring swift environmental recovery without intrusive soil excavation.
The device’s operational simplicity and autonomy are transformative in the field of soil decontamination. Its reliance on solar power circumvents infrastructure challenges common in disaster-affected or rural environments, where electricity and water resources may be scarce or unreliable. The system’s compact and modular design allows for straightforward installation and scalability, meaning that it can be tailored to varying degrees of contamination and land area. Moreover, by removing the need for soil excavation, the device mitigates risks associated with dust dispersal and secondary contamination, enhancing safety for workers and nearby populations.
Professor Seongkyun Kim highlighted the broader significance of this innovation, emphasizing the longstanding gap in effective soil cesium decontamination technologies. He noted, “Radioactive cesium contamination in soil represents a far more difficult problem than in water, yet until now, no suitable purification method existed. This technology not only harnesses the power of sunlight but also translates the elegance of natural transpiration processes into a practical device that requires no complex infrastructure or ongoing resource input.” His remarks underscore the potential paradigm shift this device could introduce in environmental remediation strategies.
The multidisciplinary study involved contributions from Soobin Kim, a doctoral student at DGIST, who played a pivotal role as the first author. The research findings were published online on August 25, 2025, in Environmental Science & Technology, a respected international journal specializing in environmental research. The publication has since attracted attention for its innovative approach to an age-old environmental problem, marrying biomimicry with advanced materials science and sustainable engineering.
The implications of this research extend beyond nuclear contamination alone. The principles underlying this artificial transpiration device could inspire future adaptations targeting a variety of soil pollutants, including heavy metals and organic contaminants. By refining the specificity and adsorption capacity for different toxic ions, this technology has the potential to revolutionize soil remediation at large, making contaminated land safe for agriculture, habitation, and ecological restoration faster than ever before.
In the context of global efforts to remediate contamination and reduce environmental health risks from radioactive materials, this technology provides a beacon of hope. It addresses both ecological and socio-economic concerns by safeguarding food security, preventing radioactive bioaccumulation in the food chain, and reducing cleanup costs. As nations continue to grapple with nuclear legacies and accidental releases, the deployment of such solar-powered, low-maintenance devices may become a standard element in environmental restoration toolkits.
The research team continues to optimize the device, focusing on enhancing the adsorption material’s longevity and broadening the spectrum of contaminants it can target. Field trials are anticipated to validate lab-scale results in diverse climates and soil types, further proving the device’s practical applicability. This pioneering work redefines the intersection of renewable energy usage and environmental remediation, promising a cleaner and healthier future through elegant, nature-inspired technological innovation.
Subject of Research: Soil purification of radioactive cesium using a solar-powered artificial transpiration device
Article Title: [Not provided]
News Publication Date: 25-Aug-2025
Web References: http://dx.doi.org/10.1021/acs.est.5c03657
References: Published in Environmental Science & Technology
Image Credits: [Not provided]
Keywords
Hydrological cycle
