Cleaner continuous flow production of mesoporous calcium-magnesium silicate as a potential biomaterial

Dolomite is an abundant, naturally occurring carbonate mineral, but the conventional processes of converting dolomite to new materials are time-consuming and energy-intensive. In addition, products from dolomite such as magnesium oxide, magnesium carbonate, magnesium hydroxide, which are used as adsorbents and additives, are mostly low value-added. Here, we demonstrated the conversion of dolomite to a mesoporous calcium-magnesium silicate (m-CMS) using a green and efficient continuous-flow synthesis method. The samples were characterized using powder X-ray diffraction, Fourier transformed infrared spectroscopy, N₂ adsorption/desorption isotherms, thermogravimetric analysis, scanning electron microscopy and transmission electron microscopy. The material possessed mesoporosity and exhibited high a specific surface area of 629 m²/g and a pore volume of 0.66 cm³/g. The maximum water absorptivity of the sample was 52.6%. After the m-CMS immersing in Tris–HCl solution for 56 days, the weight loss ratio reached 30 wt%, indicating its good potential biodegradability. Hydroxyapatite was formed on the surfaces after the m-CMS was immersed in simulated body fluids. The m-CSM provided nucleation sites, and subsequently supplied Ca²⁺ for hydroxyapatite crystal growth, indicating that the material has potential bone conduction capability. This work suggests that m-CMS can be synthesized from dolomite and tetraethyl orthosilicate through a quick continuous process, and that the m-CMS could be used as a biomaterial.