Novel poly-D-galacturonic acid methyl ester grafted vinyl monomer polymer super green adsorbent via C-O strategic protrusion of methyl methacrylate (MMA) for removal of Sm (III) and Nd (III)

In recent years, the world-wide demand for valuable Sm(III) and Nd(III) is at perpetual boost owing to their crucial role in magnet industries and metallurgy. Their critical availability demands immense exploration concern in their procurement through secondary resources such as industrial wastewater. Hence, in this regard, we explored the viability of using naturally available Poly-D-galacturonic acid methyl ester for the selective recovery of Sm(III) and Nd(III) via morphological modification. Grafted (GA)-MMA[Methyl Methacrylate]-PDGAME(Poly-D-galacturonic acid methyl ester), a novel green graft copolymer was synthesized by using radical graft copolymerization technique. The free radicals participation involved in the reaction synthesis was spotted using EPR technique. Monomer concentration parameter was optimized to obtain maximum graft yield and exceptional removal (84%, 87%) at low concentration and (63%, 58%) at high concentration for Sm(III) and Nd(III) respectively. Batch adsorption studies were directed to understand the surface charge distribution, adsorption capacity and equilibrium condition of the adsorption process. The experimental data on Sm(III) uptake was best pertinent by Langmuir isotherm whereas Freundlich isotherm was applicable in the case of Nd(III) where both followed pseudo-second-order kinetic models. Extensive microstructural analysis of all the synthesized adsorbents were executed through XPS, FTIR, TGA, SEM, TEM, AFM, BET, and CHNS/O. The successful incorporation of MMA onto PDGAME of microporous structure, the significant surface area value of grafted polymer matrix as compared to parental polymer along with the existence of relative functional groups in addition to remarkable adsorption capacity for Sm(III) and Nd(III), revealed the pronounced adsorptive potential of PDGAME for REEs.