Bioactive nanocrystalline wollastonite synthesized by sol–gel combustion method by using eggshell waste as calcium source

The sol–gel combustion method was employed to synthesize the nanocrystalline wollastonite by taking the raw eggshell powder as a calcium source and TEOS as a source of silicate. Glycine was used as a reductant or fuel and nitrate ions present in metal nitrate acts as an oxidizer. The phase purity of the wollastonite was analysed by powder XRD and the product is found to contain single-phasic wollastonite. FT–IR spectrum shows the characteristic peaks of the functional groups present in the wollastonite. SEM images show that particles are agglomerated and the particle size is found to be in the nanoregime. The calcination temperature was optimized based on the thermal analysis of the precursor. The bioactivity of wollastonite was investigated by immersing the scaffold in a simulated body fluid for 15 days at 37 °C and intermediate analysis of the surface by XRD shows the deposition of hydroxyapatite layer after 5 days.