Fabrication of high performance amine-rich magnetic composite fibers for the recovery of precious Pt(IV) from acidic solutions

Magnetic nanoparticles (MNPs) possessing a high surface to volume ratio, copious chemically active sites, and ease of separation from aqueous solutions are emerging materials for water treatment. Further encapsulation of these nanoparticles (NPs) with polymeric materials may protect these NPs from direct contact with the aqueous environment and also enhance their sorption efficiency. In the case of polymer fibers, breakage will occur depending on environmental conditions, and the addition of MNPs in fibers will provide an opportunity for the complete recovery of fibers after the sorption process. In the present study, a mixed solution of amine-rich chitosan (CS) and polyethyleneimine (PEI) containing magnetic MnFe₂O₄ nanoparticles was utilized for fabricating versatile and robust magnetic polymer composite fibers (MPCFs) in a facile methodology. The effective fabrication of MPCFs was confirmed by using analytical techniques such as FTIR, XRD, VSM, FE-SEM, and TEM. Morphological characterization demonstrated that MnFe₂O₄ nanoparticles were well distributed in the composite fibers. Detailed batch sorption experiments revealed that MPCFs exhibited significant improvement in adsorption efficiency compared with bare MnFe₂O₄ nanoparticles. The MPCFs exhibited high adsorption capacity (371.35 ± 16.79 mg g^-1) and fast equilibrium (within 30 min). The Pt-loaded MPCFs were easily separated from aqueous solution under an external magnetic field. It can be concluded that MPCFs with amine-rich functional groups and magnetic properties are promising for Pt adsorption from aqueous solutions.