Dithiocarbamate-incorporated monodisperse polystyrene microspheres as specific sorbents: Adsorption of cadmium ions

In this study, adsorption of cadmium ions from aqueous solutions by using dithiocarbamate-incorporated monodisperse crosslinked polystyrene (PS)-based sorbents was investigated. Monodisperse PS microspheres with a diameter of 2 μm were produced by dispersion polymerization of styrene in isopropyl alcohol/water by using polyvinylpyrrolidone and azobisisobutyronitrile as stabilizer and initiator, respectively. These microspheres were then crosslinked by using divinylbenzene. In order to incorporate dithiocarbamate functional group on the PS microsphere, first benzylamine was physically absorbed, then the amine groups were transformed into dithiocarbamate groups by interacting these microsphere with carbon disulphide. These PS-based sorbents carrying physically entrapped benzyl dithiocarbamate were characterized by scanning electron microscopy, optical microscopy, FTIR, and elemental analysis. Adsorption of cadmium ions on the PS-based sorbents were investigated in the batch equilibrium experiments by using atomic absorption spectrophotometer. Adsorption rates were very fast. Adsorption equilibria were achieved within 5-60 min. The highest adsorption capacity achieved was 154.1 mg cadmium/g sorbent. The most suitable pH was 6.0.