Development of phosphoryl-functionalized algal-PEI beads for the sorption of Nd(III) and Mo(VI) from aqueous solutions – Application for rare earth recovery from acid leachates

Alginate-PEI beads are functionalized by phosphorylation and applied for the sorption of Nd(III) Mo(VI). The successful grafting phosphoryl groups (as tributyl phosphate derivative) is characterized FTIR XPS analysis, elemental titration (pHPZC), TGA, BET SEM-EDX analyses. multi-functional characteristics sorbent (i.e., carboxylic, hydroxyl, amine groups) contribute in binding metal ions having different physicochemical behaviors. strongly increased phosphorylation, while Mo(VI) enhancement rather limited. Optimum occurs at pH 3–4: maximum capacity reaches up to 1.46 mmol g?1 2.09 g?1; isotherms fitted Langmuir equation. equilibrium reached within 30–40 min kinetic profiles simulated pseudo-first order rate coefficients effective diffusivity close self-diffusivity water; as a confirmation limited impact resistance intraparticle diffusion control. selective over other alkali-earth or base metals (at 2.5–3). Metals can be readily desorbed using 0.2 M HCl/0.5 CaCl2 eluent. loss does not exceed 5% fifth cycle, desorption remains complete. A series treatments (including acidic leachate, cementation, precipitation, elution) successfully recovery rare earths from Egyptian ore; with enrichment oxalate precipitate Nd(III), Gd(III), Sm(III) Eu(III).