Synthesis of ?-aminophosphonate based sorbents – Influence of inserted groups (carboxylic vs. amine) on uranyl sorption

A one-pot synthesis procedure is designed for preparing three ?-aminophosphonates (R-H, R-COOH, and R-NH2); through the reaction of amine precursors (aniline, anthranilic or o-phenylene diamine, respectively) with salicylaldehyde triphenylphosphite, under controlled conditions. These materials are first characterized by elemental analysis, FTIR, 1H NMR, 31P BET, DLS, pHzpc, TGA titration. In a second step, sorption properties compared U(VI) recovery from mildly acidic solutions. At optimum pH (i.e., 4) sorbents can be ranked according series: R-H (1.057 mmol U g?1) > R-NH2 (0.746 R-COOH (0.533 g?1). The isotherms fitted Langmuir equation. Uranium uptake relatively fast: selected experimental conditions, equilibrium reached within 90 min contact. kinetic profiles indistinctly model resistance to intraparticle diffusion pseudo-first order rate study thermodynamics shows substantial changes between sorbents: uranyl endothermic sorbents, while exothermic sorbent. diversity in functional groups speciation sulfuric acid solutions induce metal-binding combination chelation anion-exchange mechanisms (in function pH). Sodium bicarbonate achieve complete desorption uranium loaded-sorbents; resins recycled minimum 4–5 cycles limited loss efficiencies. successful application these ore leachates demonstrates their promising valorization low-grade ores.