Efficient removal of Co(II) and Sr(II) from aqueous solution using polyvinyl alcohol/graphene oxide/MnO composite as a novel adsorbent.

In this study, a novel adsorbent, polyvinyl alcohol/graphene oxide/MnO composite was prepared, characterized and used for efficient removal of Co and Sr from aqueous solution. Polyvinyl alcohol (PVA) and Mn played a synergistic role in the gelation of PVA/GO/Mn, while Mn can be further converted into oxide to achieve functionalized aerogel (PVA/GO/MnO). The spectroscopy analysis manifested that hydrogen bonds and electrostatic attraction were responsible for the formation of PVA/GO/MnO. The functionalization of MnO enhanced the adsorption capacity for Co (2.1 folds) and Sr (1.3 folds) by PVA/GO/MnO. The composite showed high adsorption capacity at broad pH range of 4.0-9.0. For competitive adsorption test, Ni/Zn exerted the most interfering effect on Co adsorption, while Mg/Ca showed severe interfering effect on Sr adsorption. Both electrostatic attraction and oxygen-containing groups contributed to the adsorption mechanism. This study may provide a new adsorbent for separation of Co and Sr from aqueous solution.