Abstract: A new magnetic amino-functionalized polymeric sorbent based on glycidyl methacrylate
was synthesized and used in the separation of chromium Cr(VI) oxyanions sorption from aqueous
solutions in a static batch system. The kinetic and isothermal parameters of the sorption process were
determined. The experimental data were best fitted by a pseudo-second-order model with R
2 = 0.994
and χ
2 = 0.004. The sorption process of Cr(VI) removal by amino-functionalized sorbent was controlled by both intraparticle diffusion and liquid film diffusion. The equilibrium results showed that
the sorption process is best described by the Freundlich model, followed closely by the Sips isotherm
model, with a maximum sorption capacity of 64 mg/g. Quantum chemical modeling revealed that
the sorption sites on the sorbent surface are fragments with diethylenetriamine and aminopropyl
silane groups that coated the magnetic nanoparticles. The calculations showed that Cr(VI) oxyanions
(Cr2O7
2−, CrO4
2− and HCrO4
−) bind to both sorption sites, with diethylenetriamine centers slightly
favored. The X-ray photoelectron spectroscopy (XPS) spectra demonstrate that the chromium bound
to the sorbent in the form of Cr(III), indicating that the Cr(VI) can be converted on the surface of the
sorbent to a less harmful form Cr(III) due to the sorbent’s chemical composition.
