Pure MgO and Cu-doped MgO nanopowders was obtained by a chemical co-precipitation process. The influence of copper doping on the crystal structure and particle morphology of MgO is discussed. The XPS results indicate that the Cu ion has been successfully incorporated into the MgO lattice. Adsorption tests show that the pseudo-second-order fitting equation is better for describing the adsorption kinetics of chlorine on MgO nanoparticles. The antibacterial properties of MgO nanopowders were investigated, as well as the influence of storage time on the adsorption and the antibacterial properties. (C) 2014 Elsevier Ltd. All rights reserved.