Effective adsorption of thorium ion by novel self-crosslinking polyamide acid-grafted magnetic nanocomposites

A novel self-crosslinking polymer-coated magnetic nanosorbent (Fe3O4@PAA) was prepared to remove thorium ions from aqueous solutions. The grafting-polymerization method was employed to graft polyamide acid (PAA) onto amino-activated magnetic nanoparticles (Fe3O4@SiO2-NH2) via an amidation reaction using pyromellitic dianhydride (PMDA) and tris(2-aminoethyl)amine (TA) as monomers. The adsorption results show that the adsorption process of Th(IV) by Fe3O4@PAA is significantly pH-sensitive, and the theoretical maximum adsorption capacity can reach 122.5 mg/g at pH 3.0. Furthermore, Fe3O4@PAA exhibits a high adsorption rate and the adsorption equilibrium could be reached within 60 min. After 5 cycles of reuse, the adsorption capacity was still retained at more than 80 % of the initial value. In addition, the extraction mechanism of Fe3O4@PAA for Th (IV) ions was analyzed in detail by FT-IR and XPS. This work provides valuable insights into the design and preparation of novel, acid-resistant, easily separable and fast magnetic separation adsorbents for the highly effective separation of Th () from aqueous solutions.

Automated summary

A novel self-crosslinking polymer-coated magnetic nanosorbent (Fe3O4@PAA) was prepared for the removal of thorium ions from aqueous solutions. The adsorbent exhibited a high adsorption rate and capacity, as well as good reusability. The extraction mechanism of thorium ions by the adsorbent was analyzed, providing valuable insights for the design and preparation of highly effective separation adsorbents.