Introduction. Hardystonite (Ca2ZnSi2O7) is a novel promising compound for bone tissue engineering due to its biocompability and favorable mechanical properties. Currently, widely used methods include mechanochemical and sol–gel synthesis of Ca2ZnSi2O7. But these methods require specialized equipment and reagents. Herein, we present a simple and efficient method for the synthesis of hardystonite.
Methods. Synthesis was carried out by a wet method based on the formation of low soluble compounds in aqueous solution. Briefly, aqueous solutions of Ca(OH)2, Na2SiO3, and ZnCl2 were consistently mixed, maintaining a molar ratio closely approximating the stoichiometry of the following theoretical reaction: 2Ca(OH)2 + 2Na2SiO3 + ZnCl2 = Ca2ZnSi2O7 + 2NaCl + 2NaOH + H2O. The resulting precipitate was aged in the mother solution, then filtered, washed with distilled water, dried, and calcined at 1250°C. The product was characterized using X-ray diffraction (XRD), infrared spectroscopy (IR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). Zeta potential and specific surface area were also determined.
Results. According to XRD and IR, freshly precipitated powder consists of poorly crystalline calcium silicate hydrate and hydrated zinc oxide, with calcium carbonate impurity. Upon calcination, dehydration and decarbonation occur, leading to the crystallization of Ca2ZnSi2O7 via solid-state reactions between the formed precursors. The resulting powder exhibits a zeta potential of -16.3 mV and a specific surface area of 1.7 m2/g.
Conclusions. This study demonstrates that single-phase hardystonite powder can be effectively synthesized via a facile and productive chemical precipitation method, followed by calcination of the resulting precipitate. This approach offers a compelling alternative to existing synthetic routes, potentially facilitating broader research and application of hardystonite in bone tissue engineering.
