111In-hydroxyapatite nanoparticles: sorption studies

Abstract This research examines the ability of hydroxyapatite to adsorb and desorb 111 In under various conditions. High crystallinity hydroxyapatite showed rapid 111 In sorption within just 3 min, with consistent pH levels. Adsorption remained stable over a broad pH range, and the results were well-fitted by Langmuir and Freundlich isotherms, with maximum capacities of 0.437 and 0.605 mmol g −1 . Organic ligands maintained high sorption while competitive ions like Fe 3+ and Al 3+ reduced 111 In sorption efficiency significantly. Oxalic acid and carbonate ions proved most effective for desorption of 111 In, highlighting hydroxyapatite´s potential as a sorbent for this radioisotope.