Synthesis of polyamide 6/nano-hydroxyapatite hybrid (PA6/n-HAp) for the sorption of rare earth elements and uranium

Polyamide (PA6) and hydroxyapatite (n-HAp) have intrinsic sorption properties for metal ions. Their association by melt compounding allows manufacturing a composite material (PA6/n-HAp) efficient the binding of uranyl rare earth ions (REEs) in acidic solution (in pH range 2–2.5). The shows enhanced capacities (5–7 times) compared with single PA6 material. structuration slightly improves textural but contributes to improve accessibility availability reactive groups (including size distribution). Metal proceeds mainly through complexation amide as shown FTIR characterization (modification environment CO NH groups) rather than ion-exchange/electrostatic attraction. Maximum approach 0.34 mmol U g?1, 0.49 Er g?1 0.70 Nd g?1: preference may be correlated covalent ionic character these Uptake kinetics are relatively slow (requiring up 6?8 h, under selected experimental conditions): (pore size: 2.6 nm) limit mass transfer (though precursor). resistance intraparticle diffusion constitutes major controlling step uptake kinetics. Nitric acid is most eluent desorption loaded metals (efficiency exceeds 94 %); noticeably U(VI) elution optimal at 1 M HNO3 concentration, contrary REEs that require lower concentration (i.e., 0.1 M). Preliminary tests on sulfuric leachates Egyptian ores demonstrate sorbent maintains good despite complexity solution. has marked REEs, Th against base alkali metals.