The effect of a molecular weight and an amount of PEGDA (poly(ethylene glycol)diacrylate) on a preparation of sodium methallyl sulfonate-co-PEGDA microspheres and sorption behavior of Co(II)

Sodium methallyl sulfonate-co-poly(ethylene glycol) diacrylate (SMS-co-PEGDA) microspheres were synthesized via suspension polymerization. The chemical structures and compositions of the microspheres were characterized using Fourier transform infrared (FT-IR) spectrometry and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), respectively. The basic properties of the SMS-co-PEGDA microspheres, i.e., the ion-exchange capacity (IEC), water uptake and yield were determined using titrimetric and gravimetric methods. The water uptake and IEC of the microspheres increased as the PEGDA content decreased; however, their yield increased as the PEGDA contents and average molecular weights Mn increased. The Co(II) sorption characteristics of the SMS-co-PEGDA microspheres obeyed the Langmuir and Freundlich sorption isotherms. At a pH below 8, Co(II) sorption increased as the initial cobalt ion concentration increased. The surface morphology was investigated using scanning electron microscopy (SEM) and optical microscopy (OM), and the roughness of the microspheres was observed to increase as the molecular weight of the PEGDA increased.