Adsorptive removal of Sr(II) from aqueous solution by polyvinyl alcohol/graphene oxide aerogel.

In this study, a new adsorbent, polyvinyl alcohol (PVA) and graphene oxide (GO), was prepared, characterized and used for the removal of Sr from aqueous solution. In PVA/GO composite, the inter-lamellar spacing of adjacent GO layers was dramatically enlarged due to the intercalation of PVA molecules, such a unique architecture significantly mitigated the aggregation of GO layers, which facilitated the accessible exposure of active sites and the mass transfer of strontium ions (Sr), thus enhancing the adsorption capacity toward Sr. The adsorption of Sr by PVA/GO composite conformed to the pseudo second-order kinetic model (R = 0.9994), the Langmuir model (R = 0.9042), and the Freundlich model (R = 0.9598). The complexation interaction between Sr and oxygen atoms/π-electron domain of PVA/GO composite was primarily responsible for the adsorption mechanism, based on the characterization results of X-ray photoelectron spectroscopy (XPS), scanning electron microscope equipped with energy dispersion spectroscopy (SEM-EDS) and powder X-ray diffraction (PXRD).