Understanding the Adsorption Behavior and Mechanism of Pt(IV) and Pd(II) on Super Amino-Modified Monodispersed PGMA Microspheres

Abstract

The present investigation described the application of high-capacity amino-group-functionalized polyglycidyl methacrylate monodispersed microspheres (PGMA-N) in the adsorption of Pt(IV) and Pd(II) ions from simulated wastewaters. The adsorption capacities of Pt(IV) and Pd(II) on PGMA-N were determined to be 3.93 and 4.99 mmol•g −1 , respectively, at 298 K and pH ∼ 4. These capacities are greater than those reported for other adsorbents in the literature. Rapid adsorption kinetics were observed for Pt(IV) and Pd(II) on PGMA-N; equilibrium was reached within 15 min. Co 2+ , Cu 2+ , Ni 2+ , Fe 3+ , Al 3+ , and Cr 3+ were utilized as representatives for competitive adsorption of metal ions, and the good separation selectivity of PGMA-N was observed for Pt(IV) and Pd(II) at pH 1−3. The pH range in which the adsorbent demonstrated optimal selectivity was extended to 1−6 with the addition of EDTA. The −NH 2 , −NH− functional groups on PGMA-N form stable, five-membered chelate rings through synergistic coordination with Pt(IV) or Pd(II), as determined by zeta potential, pH titration, XRD, FTIR, and XPS analysis.

Adsorption Behavior and Mechanism of Palladium on Diethylaminoethyl-Modified Polyglycidyl Methacrylate Macroporous Spheres

“…PGMA microspheres have been investigated for their application in various fields, such as catalyst supports, , drugs, genes, and cell vectors, , and frameworks for complex architectures. , The application of PGMA microspheres as adsorbents for water treatment and removal and recovery of metal ions has been extensively studied. In these studies, PGMA microsphere structures were modified with various functional groups, such as ethylenediamine, − diethylenetriamine, triethylenetetramine, , polyethylenimine, , iminodiacetic acid, aminoalkylcarboxylate, and aminoalkylphosphonic ligands . These investigations revealed that while certain metal ions, such as Co­(II), Cu­(II), Ni­(II), Hg­(II), Cd­(II), Au­(III), Pt­(IV), Pd­(II), Pb­(II), Zn­(II), and Nd­(III), form coordinate bonds with the PGMA surface, others, such as Cr­(VI) and As­(V), bind to the PGMA surface through electrostatic interactions.…”