Synthesis Of Highly Dispersed MgO Nanoparticles And Its Property Investigations

Benefiting from its unique rock salt structure,magnesium oxide?MgO?nanoparticles could be utilized as functional ceramics,catalysts,absorbents,cosmetics,non-firing materials,anti-bacterial materials,microwave absorbing materials and so on.However,on sharply decreasing the size of bulk materials to nano-meter,nanoparticles are facilitated to form large agglomerations due to the quickly increased surface energy,thereby sacrificing the unique properties of nano-materials.Therefore,it is one of the key points to prepare uniformly dispersed Mg O nanoparticles for making their potential applications in different fields valid.Taking the merits of polyol method into consideration,this study primarily synthesized uniformly dispersed Mg O nanoparticles by using Mg Cl2,urea and ethylene glycol?EG?as reactant,precipitator and solvent,respectively.As prepared samples were characterized by X-ray diffraction?XRD?,Thermal Gravimetric/Differential Thermal Analysis?TG/TGA?,Frourier Transform Infrared Spectroscopy?FT-IR?,Field-emission Scanning Electron Microscope?FE-SEM?,High resolution-Transmission Electron Microscope?HR-TEM?and Selected area electron diffraction?SAED?.Based on the characterization results,it is concluded that the precursor prepared by this method was identified to hydro basic magnesium carbonate?HBMC?.As the reaction solution containing 0.4 mol/L was reacted at110 ? for 8 h,as-prepared precursor was pompon-like HBMC with self-assembled nano-sheets.The size of these pompon like particles is about 3⁵ ?m.While it changed to sphere-like nanoparticles once the Mg²⁺ concentration was adjusted to 0.2mol/L.Generally,the optimum preparation condition for precursor via a modified polyol method is: the 0.2 mol/L Mg²⁺ reaction system was reacted at 110 ? for 8 h.In a word,EG not only serves as solvent,but also acts as surfactant,thereby leaving the high uniformity.Because the crystal water supply the precipitation condition for Mg²⁺,precisely control the water amount in reaction system is one of the key points that if we can prepare Mg O nanoparticles or not.There is a systematic study about the influence of water content in this reaction system on the precursor and Mg O.The results show thatthe change of water in the solvent content can change the structure of the precursor and growth,which affects its morphology.Increasing the content of water in the reaction system,the precursor is change as nano particle to dendritic to nano film.When the added water in EG is up to 25 m L,as-prepared precursor change from nano-sphere to nano-plate.The thickness and the size of nano-plate are around 1.5 ?m,respectively.Mg O nanoparticles were prepared after calcination of as-prepared precursor powders under optimum synthesis condition.It is confirmed in this study that,after calcination at 700 ? for 3 h,these precursors were totally converted to Mg O via dehydration and decarbonization processes during calcination.While the plate-like precursor prepared from the mixture of water and EG with different proportions were converted to porous Mg O nano-plate.Because the Mg O nanoparticles prepared by this modified have abundant active sites on their surfaces,they have high absorptive performances toward boron and Sr²⁺in aqueous solution.And the absorptive efficiency toward boron and Sr²⁺ is up to96 % and 70 %,respectively.