Sodium “Activation” of Silano‐Phosphonate Modified Mesoporous TiO 2 Leading to Improved Rare‐Earth Element Extraction

Due to their presence in most modern electronic devices and as waste products in the nuclear cycle, a great deal of interest has been generated in the acquisition and/or recycling/removal of rare‐earth elements (REE). Here, we present a simple one‐pot route for the preparation of dimethylphosphatoethyltriethoxysilane (SiP) functionalised mesoporous TiO 2 particles. The resistance of TiO 2 to strong bases allowed for the use of NaOH to “activate” the phosphonate head group of the functionality, significantly improving its efficiency. Levels of 92.6 mg/g Ce 3+ were extracted from water, which is double the previously reported value for the extraction of REEs with this type of extractant. SiP‐TiO 2 (Na) was also used to separate completely the Ce 3+ from aqueous solutions containing Sr 2+ and Cs + . Finally, the nanocomposite separated Ce 3+ from other homovalent REEs, for example, Yb 3+ (1:1.4 separation ratio).