Interfacially‐Engineered Lanthanum‐Loaded Polyurea Aerogel Monolithic for Fluoride Removal From Challenging Water Environments

ABSTRACT The robustness of adsorbent materials is challenged by effluents from the new energy industry, which contain fluoride. This work describes a monolithic lanthanum‐loaded polyurea aerogel (La‐PUA) produced via interfacial engineering. A high density of adsorption centers forms as La 3+ sites become attached to the polyurea framework. Simultaneously, La 3+ acts as a coordination‐based cross‐linker, improving the aerogel's mechanical properties. The material sustained up to 60% strain without breaking, and its compressive strength increased by about 91%, from 3.61 to 6.89 MPa. The aerogel also exhibited thermal stability, with an initial decomposition temperature of 234.5°C, which is 104.5°C higher than that of pure PUA. La‐PUA exhibited minimal La leaching (as low as 0.07 mg/L) and high fluoride removal efficiency (> 97%) across a pH range (2–10) and in the presence of competing anions. After six adsorption–desorption cycles, the material maintained structural integrity and removal efficiency above 77%. This work shows that interfacial engineering enhances aerogel performance and presents an approach to developing adsorbents capable of withstanding demanding conditions.