Synthesis of shape and structure-dependent hydroxyapatite nanostructures as a superior adsorbent for removal of U(VI)

•Shape and structure-dependent HAP nanostructures were hydrothermally synthesized.•The temperature was a vital factor affecting the morphology and structure of HAP.•Growth mechanism involved anisotropic growth, further growth and Ostwald ripening.•HAP-180 exhibits excellent performance on removal of radioactive uranium.•Removal mechanism involved adsorption, complex reaction and precipitation.