Versatile Zwitterionic Beads for Heavy Metal Ion Removal from Aqueous Media and Soils by Sorption and Catalysis Processes

Cross-linked polymeric beads of divinylbenzene/ethyl acrylate/acrylonitrile copolymer, with zwitterionic functional groups obtained by aminolysis with ethylenediamine and carboxymethylation with sodium chloroacetate (IEx-Zw) were herein used in the heavy metal ions (HMIs) dynamic sorption studies, both as a single component-simulated solution (Cu2+) and in multicomponent polluted water (Cu2+, Fe2+, Mn2+, and Zn2+) collected from tailings pond of Tarnita, Suceava, Romania. The experiments were performed in fluidized bed columns filled with IEx-Zw, for the column sorption of Cu2+ from synthetic polluted waters being used to assess the best working conditions of the sorbent. The HMIs sorption experiments were supported by UV-Vis spectroscopy, atomic absorption spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and thermogravimetric analysis. The dual sorbent/catalyst function of the IEx-Zw was followed in the copper sorption experiments, with sorbed Cu2+ being reduced to Cu2O, as found by X-ray diffraction analysis of the obtained precipitate. The multicomponent HMIs sorption kinetic data were described by Thomas and Yoon-Nelson models to gain a deeper understanding of the use of the zwitterionic beads in a continuous flow setup. Furthermore, the germination assays were used to investigate the toxicity of soil collected from the Tarnita sterile dump. Soil cleaning using the IEx-Zw resin was shown to be effective enough to increase the soils' capacity to support the germination process.