Novel and effective reduced graphene oxide-nickel (Ni) doped manganese oxide (RGO/Ni-MnO 2 ) adsorbents were fabricated via a hydrothermal approach. The reduction of graphite to graphene oxide (GO), formation of a-MnO 2 , and decoration of Ni-MnO 2 onto the surface of reduced graphene oxide (RGO) were independently carried out by a hydrothermal technique. The physical and morphological properties of the as-synthesized adsorbents were analyzed. Batch adsorption experiments were performed to identify the lithium uptake capacities of adsorbents. The optimized parameters for Li + adsorption investigated were pH ¼ 12, dose loading ¼ 0.1 g, Li + initial concentration ¼ 50 mg L À1 , in 10 h at 25 C. It is noticeable that the highest adsorption of Li + at optimized parameters are in the following order: RGO/Ni3-MnO 2 (63 mg g À1 ) > RGO/Ni2-MnO 2 (56 mg g À1 ) > RGO/Ni1-MnO 2 (52 mg g À1 ). A Kinetic study revealed that the experimental data were best designated pseudo-second order for each adsorbent. Li + desorption experiments were performed using HCl as an extracting agent. Furthermore, all adsorbents exhibit efficient regeneration ability and to some extent satisfying selectivity for Li + recovery. Briefly, it can be concluded that among the fabricated adsorbents, the RGO/Ni3-MnO 2 exhibited the greatest potential for Li + uptake from aqueous solutions as compared to others. Fig. 5 Survey XPS spectrum of (a) RGO and a-MnO 2 , (b) all RGO/Ni-MnO 2 adsorbents, XPS spectra of (c) C 1s, (d) O 1s, (e) Ni 2p and (f) Mn 2p of RGO/Ni3-MnO 2 adsorbent.This journal is Fig. 8 (a) Effects of coexisting ions on the adsorption of adsorbents for Li + ; (conditions; pH 12, 0.1 g, 250 mL, 50 ppm, 24 h), (b) reusability of adsorbents for 4 sequential cycles and (c) proposed ion exchange mechanism of lithium capture by adsorbents.9254 | RSC Adv., 2020, 10, 9245-9257This journal is