Scalable solar-tracking ion-selective evaporation system for concurrent desalination and radionuclide removal

The escalating contamination of seawater with radioactive cesium ions (Cs + ) poses severe environmental and health challenges, requiring remediation strategies that are both efficient and sustainable. However, current approaches often suffer from limited selectivity, low adsorption capacity, and poor adaptability in complex ionic environments. Herein, a multifunctional Li +  − intercalated vermiculite−based photothermal aerogel evaporator is designed to synergistically couple interfacial solar evaporation (ISE) with highly selective Cs + capture. Solar-driven interfacial evaporation increases the local chemical potential of hydrated ions, while the negatively charged vermiculite nanochannels electrostatically facilitate Cs + desolvation and intercalation, enabling active ion pumping instead of passive adsorption. Consequently, the Li-V@CNTs aerogel exhibits an excellent evaporation rate of 3.33 kg·m −2 ·h −1 under 1 sun illumination, exceeding typical cellulose or graphene oxide systems (≈2.2–2.8 kg·m −2 ·h −1 ). As a Cs + sorbent, it achieves capacities up to 450 mg·g −1 in Cs + -spiked seawater, outperforming zeolite A (≈51 mg·g −1 ) and representative Zn-based metal-organic frameworks (≈221 mg·g −1 ). Integrated into a sunflower-inspired solar-tracking device, the aerogel evaporator delivers clean-water yield and Cs + removal from real seawater. Fabricated from vermiculite and bacterial cellulose via a simple, low-temperature process (estimated material cost ≈US$1.5 m −2 ) and operated solely by solar energy without secondary pollution, this ion-pumping platform offers a scalable platform with strong potential for sustainable radioactive seawater remediation.