Removal of strontium ion from aqueous solution by PS-D2EHPA beads prepared by immobilizing di-2-ethylhexyl phosphoric acid (D2EHPA) with polysulfone (PS)

PS-D2EHPA beads were prepared by immobilizing di-2-ethylhexyl-phosphoric acid (D2EHPA) with polysulfone (PS). The prepared PS-D2EHPA beads were characterized by using a Fourier transform infrared spectrometer (FTIR) and scanning electron microscopy (SEM). The removal characteristics of Sr(II) from an aqueous solution by the prepared PS-D2EHPA beads was investigated in a batch system. The kinetic data followed the pseudo-second-order kinetic model. Equilibrium data fit the Langmuir isotherm model well and the removal capacity of Sr(II) by the PS-D2EHPA beads obtained from the Langmuir model was 1.71 mg/g at 298 K. The removal process of Sr(II) by the PS-D2EHPA beads is dependent on the initial pH of the solution. The optimum removal of Sr(II) by PS-D2EHPA beads was observed in the range of pH 6–10. The values of the thermodynamic parameters such as Gibbs free energy change (ΔG°), enthalpy change (ΔH°) and entropy change (ΔS°) showed that the adsorption of Sr(II) by the PS-D2EHPA beads was feasible, spontaneous and endothermic at 298–328 K. The results implied that the prepared PS-D2EHPA beads could be an interesting alternative material for the removal of Sr(II).