Prediction and optimization of removal performance for europium onto phosphate decorated zirconium-based metal–organic framework nanocomposites: Structure-activity relationship and mechanism evaluation

•Oriented functionalization of UiO-66-PO4 was successfully prepared.•The maximal adsorption capacity of Eu(III) by UiO-66-PO4 was 3.86 × 10-4 mol·g−1.•UiO-66-PO4 revealed excellent stability in the removal of radionuclides.•The surface complexation and electrostatic interaction were primary mechanisms.•Long-term evaluation of Eu(III) performances in aqueous medium were needed.