Preparation and exceptional adsorption performance of porous MgO derived from a metal–organic framework

Abstract

Porous MgO materials have unique and highly attractive properties. In this paper, porous MgO microstructures with hexagonal and double hexagonal pyramid architectures (MgO-hex and MgO-dhp) were prepared simply by annealing Mg-based metal–organic framework [NH₄][Mg(HCOO)₃]. The monodisperse porous MgO-hex and MgO-dhp products inherit the morphologies of the [NH₄][Mg(HCOO)₃] precursors and have large surface areas. The adsorption performance of porous MgO-hex and MgO-dhp were systematically tested towards Congo red (CR) as a model pollutant. The adsorption capacities are 1380 mg g⁻¹ for MgO-hex and 1413 mg g⁻¹ for MgO-dhp toward CR after 150 minutes at the initial concentration of 1000 mg L⁻¹. The prepared MgO materials exhibit potential applications in wastewater treatment. The experimental data were fitted by two isotherm models, and the adsorption isotherm obeys the Langmuir model. Moreover, the kinetic studies indicate that the kinetic data followed a pseudo-second-order model.