5-Bromo-2,9-bis(5,6-diphenyl-1,2,4-triazin-3-yl)-1,10-phenanthrolin as an Efficient Ligand for Selective Removal of Strontium and Cobalt from Aqueous Solution

In this study, 5-bromo-2,9-bis(5,6-diphenyl-1,2,4-triazin-3-yl)-1,10-phenanthroline (5-bromo-Ph4-BTPhen) was synthesized and evaluated for its ability to remove major radionuclides (Cs ⁺ , Sr ²⁺ , and Co ²⁺ ). The synthesized ligand removed both Sr ²⁺ and Co ²⁺ from 1 mg/L aqueous solutions with extraction efficiencies of up to 99% at neutral and alkaline pH. The Sr ²⁺ and Co ²⁺ removal efficiencies decreased as a consequence of the higher bonding strengths of competing metal ions to the N-donor atoms in the cavity of the ligand; competing divalent ions affected the Sr ²⁺ and Co ²⁺ removal efficiencies more than monovalent ions.