Pore size and surface area control of MgO nanostructures using a surfactant-templated hydrothermal process: High adsorption capability to azo dyes

► A novel mesoporous MgO adsorbent with higher surface area was prepared. ► The mechanism for designing the porous structures in MgO was proposed. ► The MgO materials exhibit high adsorption capability to azo dyes. ► The MgO show good performance for decolorization of low concentration dyes. ► The ability to obtain such MgO structure is useful in other adsorbent preparation.