Synthesis of flower-like porous MgO microspheres via a gas-liquid interfacial reaction

Flower-like hierarchical porous MgO was obtained via a modified gas-liquid interfacial reaction. These resulting MgO powders showed superb adsorption properties, with a notable adsorption capacity of 5051 mg g−1 for Congo red. [Display omitted] •Flower-like porous MgO was obtained via a gas-liquid interfacial reaction.•This porous MgO displayed an ultra-high adsorption capacity for Congo red (5051 mg g−1).•The possible formation mechanism of basic magnesium carbonate microspheres using ammonium carbonate and aqueous ammonia has been proposed. The flower-like porous MgO was obtained via a interfacial reaction following by further calcination. In the interfacial reaction, flower-like basic magnesium carbonate microspheres (precursor) were prepared by using magnesium chloride hexahydrate, ammonium carbonate, aqueous ammonia and water as starting materials. The formation mechanism of these basic magnesium carbonate microspheres has been proposed. The as-obtained hierarchical porous MgO showed an ultra-high adsorption capacity for Congo red (5051 mg g−1). This study provides a convenient strategy for synthesizing hierarchical porous MgO microspheres with great adsorption ability.