Magnesium oxide nanomaterial for carbon capture and potential biomedical applications

Abstract

Metal oxides, specifically alkali metal oxides and alkaline earth metal oxides, represent a class of crystalline solid that contains metal cations and oxide anions. Among these metal oxides, magnesium oxide (MgO) has been extensively studied due to its abundantly existing precursors in nature and its applicable physical and chemical properties for water remediation, air emissions treatment, and some medical applications. In the first part of this work, a method of using metal organic frameworks (MOF) as a template material for the synthesis of porous oxide for carbon capture and storage (CCS) was explored to address the overwhelming global climate change issue. Particularly, the solution of how to prevent magnesium oxide particles from sintering during cyclic adsorption and desorption of carbon dioxide (CO2) was inspected. The results showed that a regenerable porous magnesium oxide with high CO2 capture capacity and material regenerability was achieved via this synthesis method. This work suggested that the carbon contents remaining on the surfaces of magnesium oxides may preserve its porous structure and prevent further sintering and structure collapse of the material, evidenced by the adsorbent's retained porosity and capture capacities over repeated carbonation and decarbonation cycles. This demonstration of the synthesis of regenerable metal oxides by thermal decomposition of MOF templates may enable broader applicability for other energy-related metallic oxides. The next part of this work aimed to investigate porous MgO coatings for implants to combat bacterial infections during surgical procedures. In particular, the correlation between surface area/pore volume of obtained MgO and its antibacterial activities was studied. The results of this study suggested that higher surface areas provided better inhibition on both Gram-positive bacteria, methicillin-resistant Staphylococcus aureus and Gram-negative bacteria, Pseudomonas aeruginosa. Those results offered a new perspective to better understand the bacteria-killing mechanism of magnesium oxides and even other metallic oxides.