he widespread clinical utilization of ⁹⁰Y for preparation of target specific radiopharmaceuticals stipulates design of superior advanced materials for facile and cost effective separation of ⁹⁰Y. We demonstrate for the first time potential of birnessite type phylomanganates for radiochemical separation of clinical grade ⁹⁰Y from ⁹⁰Sr/⁹⁰Y mixture. Sodium birnessite was synthesized by controlled oxidation of MnCl₂.4H₂O in presence of excess of NaOH and characterized thoroughly for structure, microstructure and purity. Ion exchange experiments in the presence of ⁹⁰Sr/⁹⁰Y equilibrium mixture confirmed the exceptionally high selectivity of synthetic sodium birnessite for exchanging Sr²⁺ ions and the conditions have been optimized to achieve radiochemically pure ⁹⁰Y (> 80% separation yield) meeting all the pharmaceutical requirements for its clinical use. Radionuclidic purity of ⁹⁰Y could be achieved to < 1 × 10^-4 % of ⁹⁰Sr which is well below the limit set internationally (2 × 10^-3 %). The separated ⁹⁰Y has been used to prepare ⁹⁰Y radiolabeled 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid coupled dimeric cyclic RGD peptide derivative [DOTA—E[c (RGDfK)]₂] and the biological efficacy of the radiotracer was established in C57/BL6 mice bearing melanoma tumors. The results indicated highly target specific radiotherapy suggesting the potential of sodium birnessite for cost effective radiochemical separation of ⁹⁰Y.