Investigation of Minerals Extracted during Seawater Desalination Using Two-Dimensional Correlation Spectroscopy

Abstract

In this study, mineral components extracted during the desalination process were concentrated and dried, and then identified using energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), infrared (IR), and Raman spectroscopy. For detailed identification, two-dimensional correlation spectroscopy (2D-COS) was also applied to the XRD patterns, IR spectra, and Raman spectra of the minerals obtained from each desalination step. The EDS results confirm the presence of seawater minerals rich in Na+ ions in the first and second extracts, Ca2+ ions are present only in these stages, and Mg2+ ions are abundant in the third and final extracts. The presence of NaCl and MgSO4 minerals in the first to third and final extracts, respectively, was confirmed using XRD patterns. From the IR and Raman spectra, we found that the degree of hydration of SO42−-related extracts decreased as seawater underwent desalination. Furthermore, 2D-COS provides information about the changes in the extracts obtained from the first to final stage. Heterospectral XRD and Raman 2D-COS provides clear assignments for Raman spectra. The use of 2D-COS helps to understand the characteristics of seawater extracts during the desalination process, and provides a better understanding of chemical and structural adaptations within the extract. As a result, this method contributes to an improved understanding of the desalination process and final products.