Efficient removal of Co(II) and Sr(II) from aqueous solution using polyvinyl alcohol/graphene oxide/MnO2 composite as a novel adsorbent

In this study, a novel adsorbent, polyvinyl alcohol/graphene oxide/MnO 2 composite was prepared, characterized and used for efficient removal of Co 2+ and Sr 2+ from aqueous solution. Polyvinyl alcohol (PVA) and Mn 2+ played a synergistic role in the gelation of PVA/GO/Mn 2+ , while Mn 2+ can be further converted into oxide to achieve functionalized aerogel (PVA/GO/MnO 2 ). The spectroscopy analysis manifested that hydrogen bonds and electrostatic attraction were responsible for the formation of PVA/GO/MnO 2 . The functionalization of MnO 2 enhanced the adsorption capacity for Co 2+ (2.1 folds) and Sr 2+ (1.3 folds) by PVA/GO/MnO 2 . The composite showed high adsorption capacity at broad pH range of 4.0–9.0. For competitive adsorption test, Ni 2+ /Zn 2+ exerted the most interfering effect on Co 2+ adsorption, while Mg 2+ /Ca 2+ showed severe interfering effect on Sr 2+ adsorption. Both electrostatic attraction and oxygen-containing groups contributed to the adsorption mechanism. This study may provide a new adsorbent for separation of Co 2+ and Sr 2+ from aqueous solution.