Utilization of solid marine wastes from snail and cockle shells for the sustainable synthesis of nanocrystalline Gypsum

Abstract

Cockle shells and discarded snails were employed as the source of calcium in this study to synthesize industrially essential minerals, known as gypsum, utlilizing a wet chemical precipitation technique. Fourier transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), and X-ray diffraction (XRD) were used for analyzing the generated gypsums. XRD data were also used to determine several crystallographic parameters, including growth preference, residual stress, microstrain, dislocation density, crystallinity index, and crystallite size (using the Scherrer equation and other model equations). Based on the information from XRD, the previously specified models were employed to determine that all the generated gypsum displays a crystallite size within the authorized range of 1–150 nm. The images captured by the scanning electron microscope (SEM) show that the gypsum crystals have a distinct morphology that takes the shape of plates. The texture coefficient (T_c) provides an approximate representation of the given plane's texture, indicating a similar preferred orientation along the stated crystallographic planes. Furthermore, the EDX examination (Ca, S, and O percentages) and Rietveld refinement (nearly 99 % gypsum) supported the nature of the final gypsum samples.