Hypothesis: Nanoparticles functionalized with ligands which can on-demand and remotely be detached have recently attracted interest as stimuli-responsive materials. Research is now focused on multi-responsive systems, with applications in environmental science and biomedicine. The possibility to covalently couple two different ligands on a single nanoparticles, and to release them independently is investigated. This concept of nanoparticles functionalized with dual on-demand cleavable ligands is exploited in ground water decontamination and radionuclides separation. Efficient separation of contaminants in a single step is expected, simplifying partitioning process and decreasing generation of secondary waste by nuclear industry. Experiments: Sub-10 nm Janus superparamagnetic nanoparticles are functionalized by click-chemistry (thiol and Diels-Alder) with two different Actinide-specific chelators. The reversible covalent bonds allow to detach chelators independently by either pH- or thermo-stimulation. The nanoparticles decorated with diethylenetriamine-pentaacetic acid (DTPA) and [(2-furan-2-yl-2-hydroxy-ethylcarbamoyl)-meth oxy]-acetic acid (FHECMAA) are incubated with UO2'2+ and La3+ (as substitute for Pu3+) at pH = 3 and 7 before chelator-metal complexes are released. Metal contents are measured to determine separation efficiency. Findings: Chelators can be detached from Janus nanoparticles with perfect selectivity. The nanoparticles are highly efficient for extraction of metals in acidic medium and show good ability for separation of U and La at neutral pH. (C) 2018 Elsevier Inc. All rights reserved.