Functionalization of poly(glycidylmethacrylate) with iminodiacetate and imino phosphonate groups for enhanced sorption of neodymium-sorption performance and molecular modeling

Polyglycidyl methacrylate (PGMA, obtained by dispersion polymerization method) can be successfully func-tionalized to improve the sorption of Nd(III). Pristine PGMA is first modified by amination (N-PGMA), before grafting amino-alkylcarboxylate and amino-alkylphosphonic ligands to produce A-PGMA and P-PGMA, respec-tively. These materials are characterized by CHNP, FTIR-spectrometry, XRD, TG-TDA and pHzpc. Following that, the Nd(III) sorption properties are compared. At optimum pH: 4.5-5.0, the sorbents can be ranked according the series: P-PGMA (0.645 mmol Nd g- 1) < A-PGMA (0.736 mmol Nd g- 1) (vs. 0.304 mmol Nd g- 1 for N-PGMA). Sorption capacities increase with temperature. Sorption isotherms are modeled using the Langmuir equation. Equilibrium is reached within 180 min. Uptake kinetics are controlled by the resistance to intraparticle diffusion (fitted by the Crank equation). The sorption is endothermic, spontaneous and followed by an increase of the entropy of the system. Elution and regeneration are carried out using HNO3 solutions achieving >91%. Theo-retical DFT calculation (molecular modeling) and FTIR spectroscopy, the interactions of Nd(III) with reactive functional groups (carboxyl, hydroxyl, amine and phosphonate groups) are characterized. Finally, the sorbents are tested on pre-treated leachate of Egyptian monazite: REEs' sorption performances are correlated with their intrinsic properties and compared for the two sorbents.

Automated summary

Polyglycidyl methacrylate (PGMA) was functionalized to improve the sorption of Nd(III). The modified materials, A-PGMA and P-PGMA, exhibited higher sorption capacities compared to the pristine N-PGMA. The sorption isotherms were modeled using the Langmuir equation, and the sorption process was found to be endothermic, spontaneous, and governed by intraparticle diffusion. The sorbents showed high selectivity towards Nd(III) in pre-treated leachate of Egyptian monazite.