▎ 摘　　要

The individual and competitive adsorption of Pb-II, Ni-II, and Sr-II on graphene oxides (GOs) was investigated by experimental and density functional theory (DFT) studies. Experimental results indicate that 1)in all the single, binary, and ternary metal-ion adsorption systems, the sequence of maximum adsorption capacities is Pb-II>Ni-II>Sr-II on GOs; 2)the desorption hysteresis of metal ions from GOs shows the adsorption affinity in the same sequence: Pb-II>Ni-II>Sr-II. For the first time, DFT calculations indicate that 1)Pb-II and Ni-II prefer to interact with the COH group, whereas Sr-II interacts with COH and COC comparably, and 2)Pb-II can easily abstract the OH group from the GOs to form the much more stable Pb(OH)-GO complex. These findings are very important and useful for understanding the mechanisms of heavy-metal-ion adsorption on GOs and assessing the adsorption of coexisting heavy-metal ions on GOs.