Online sequential separation, preconcentration, extraction, and transport of Ti, Zr, and Hf by ICP–MS and recovery from nuclear waste

Abstract The online inductively coupled plasma mass spectrometry preconcentration, recovery, and simultaneous trace determination of titanium (Ti), zirconium (Zr), and hafnium (Hf) from sea water is described. The limit of detection is 0.05, 0.03, and 0.33 pg mL−1 for Ti, Zr, and Hf, respectively. The limit of quantification is 1.5, 1.0 and 1.0 pg mL−1 for Ti, Zr, and Hf, respectively. The use of Coumarin Calix–[4] arene hydroxamic acid (CC4AHA) for solvent extraction and separation, and the recovery of Ti, Zr, and Hf is reported. Ti, Zr, and Hf can all be quantitatively extracted from dichloromethane solutions of CC4AHA at molarities of HCl of 6.0, 8.0, and 0.6 M; Ti, Zr, and Hf are all 1:1 bound by tetracarboxy calix[6]crown hydroxamic acid. Under controlled circumstances, a study on the liquid membrane transfer of Ti, Zr, and Hf was conducted from the source to the receiving phase. The ability of the produced chelating extractant to simultaneously separate Ti, Zr, and Hf mixtures was investigated. Analysis of approved standard reference materials was performed to validate the process. The Ti, Zr, and Hf were recovered from sea water and effluents, and determined. The method extended from trace determination of these metals in standard samples of alloys and soil, and industrial samples.