Modeling and mechanism of the adsorption of copper ion onto natural bamboo sawdust

► Natural bamboo sawdust was used to adsorb copper in water. ► NEM surface complexation models gave a good fitting results. ► pH, ion strength and the hydrated ion reaction have great effect on adsorption. ► XAFS study shows that: copper ions mainly form inner complexation with sawdust. ► Spatial configuration of copper shifts from tetrahedron to octahedron as pH rises.