Removal of radiocobalt from aqueous solutions using titanate/graphene oxide composites

The titanate/graphene oxide composites were synthesized by thermal treatment using graphene oxides and TiO2 powder (P25), and were characterized using FTIR, SEM and XRD. The as-prepared titanate/graphene oxide composites were used as adsorbents to eliminate radiocobalt (60Co) from aqueous solutions as a function of contact time, ionic strength and pH values. The sorption of 60Co to titanate/graphene oxide composites was strongly dependent on pH and ionic strength at pH < 8, and was independent of ionic strength at pH > 8. The sorption of 60Co was mainly dominated by inner-sphere surface complexation at high pH and by ion exchange and/or outer-sphere surface complexation at low pH values. The sorption of 60Co on titanate and on graphene oxides was also compared, and the results indicated that the titanate/graphene oxide composites were suitable materials for the preconcentration and solidification of 60Co and/or other radionuclides/heavy metal ions from large volumes of aqueous solutions in environmental pollution cleanup in real applications.