Crystallographic characterization of gypsum synthesized from marine wastes (Babylonia japonica, Olive sayana, and Conasprella bermudensis)

Abstract

This study focused on the synthesis of gypsum nanocrystals using conventional wet chemical precipitation method from marine mollusks like Babylonia Japonica, Olive Sayana, and Conasprella bermudensis. Different characterization techniques like Thermogravimetric Analysis (TGA), X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and Energy Dispersive X-ray Spectroscopy (EDX) were used to confirm the formation of the nanocrystals. XRD data assessed various structural parameters, including the dimension of the unit cell, crystallinity index, specific surface area, lattice parameters, dislocation density, and macrostrain. The Rietveld refinement study did not reveal the formation of alternate phases, and the predicted lattice parameters, Full Width at Half Maximum (FWHM), and X-ray density contradicted the actual data. The synthesized gypsum displayed crystallite dimension within the acceptable range of <200 nm, as calculated using various XRD models and equations. Additionally, the values for strain (2 × 10⁻⁴ to 4 × 10⁻⁴), stress (−1 × 10⁷ to 2 × 10⁷ N/m²), and energy density (2.87 × 10² to 2.16 × 10³ J/m³) were also estimated for the synthesized samples. The preferential growth calculation indicateed stable phase formation of gypsum along the (0 2 0) and (0 4 0) planes. Furthermore, The study compared the properties of gypsum, including pH, conductivity, and potential difference (PD), in soil extraction and an aqueous medium.