Research on the preparation of antibacterial magnesium oxide by dolomite carbonation and its structural regulation

In response to the severe global challenge of increasing microbial resistance， developing efficient and environmentally friendly antibacterial materials has become an urgent demand in the field of materials science. This research used natural dolomite from a region in Hunan as the raw material and investigated the controllable preparation process of antibacterial magnesium oxide （MgO） via the dolomite carbonation method， focusing on the regulation mechanisms of the microstructure of the product through heavy magnesium hydrolysis methods （spray pyrolysis and vacuum pyrolysis） and precursor calcination conditions. By systematically optimizing the process parameters， the optimal calcination conditions for dolomite were determined to be 1000 °C for 180 minutes， with a carbonation endpoint pH of 7.5， under which the magnesium recovery efficiency achieved the highest. Spray pyrolysis at a feed rate of 30 mL/min and 220 °C produced well-shaped hollow spherical MgCO₃·3H₂O precursors； when this precursor was calcined at 600 °C with a heating rate of 10 °C/min for 3 hours， high-activity MgO with a high specific surface area （49.43 m²/g）， nanoscale particle size （d50=222.47 nm）， and a hierarchical porous structure was successfully obtained. Antibacterial tests showed that this MgO material achieved a 100% sterilization efficiency against Escherichia coli， with a minimum bactericidal concentration of 0.5 mg/mL， demonstrating excellent antibacterial efficacy. By constructing a "process-structure-performance" regulation system， this study provides reliable theoretical guidance and technical support for the preparation of high-performance， environmentally friendly nanostructured antibacterial materials based on natural dolomite.