Ethylene Glycol-Assisted Fabrication and Superb Adsorption Capacity of Hierarchical Porous Flower-like Magnesium Oxide Microsphere for Phosphate
A series of the hierarchical flower-like magnesium oxide (MgO) microspheres were prepared in an ethylene glycol (EG)-assisted route at room temperature using ammonia as a precipitating agent. The effect of ethylene glycol (EG) ratio on the structure, morphology and pore properties were carefully investigated. The heirarchcal porous MgO microsphere exhibited the surface area of 75 m2 g-1 and total pore area of 47.37 m2 g-1 at the highest ratio of EG (EG/Mg2+ =10) in the reaction system. The prepared MgO microspheres exhibited the outstanding removal capacity of 574.71 mg g-1 for phosphate following the pseudo second order kinetic model (R2 = 0.99) and Langmuir isotherm model with endothermic nature of phosphate adsorption, resulting from high surface area and suitable pore size. Both of the isothermal parameter RL between 0 and 1, and the negative the Gibbs free energy value suggested that the phosphate adsorption on MgO microsphere was favorable process. Undoubtedly, the template-free mild synthesis method effectively promoted wide practical applications and mass scale production of porous MgO microsphere adsorption material.