Carbon dioxide storage in Dead Sea water

Abstract

In this paper, the Dead Sea (DS) environment as a carbon dioxide (CO2) potential storage site was investigated. Firstly, the storage capacity of CO2 in ultra-pure and Dead Sea water (DSW) was studied at ambient temperature and pressure. The effect of CO2 pressure on the storage capacity of CO2 in DSW was also studied at different contact times at the ambient temperature. Finally, for comparison purposes, CO2 gas was injected into a solution containing only dissolved calcium ions. Different analytical and instrumental analysis techniques were used to characterize both liquid and solid samples including acid base titration, Atomic Absorption Spectrometry (AAS), X-ray Diffraction analysis (XRD), Thermogravimetric Analysis (TGA), and Scanning Electron Microscopy (SEM). Based on the titration method, the storage capacity of CO2 in both pure water and DSW was found to be 1.7 and 1.53mmol/l, respectively, at ambient temperature (15°C) and ambient pressure. DSW water was found to contain 1.6Ca wt% and 4.3wt% Mg based on AAS analysis. The storage capacity of CO2 in DSW increased with the increase of pressure and despite the high content of Ca and Mg in DSW, no precipitation was observed even at a CO2 pressure of 25bar and 76h of contact time. When DSW, saturated with CO2, was titrated (using NaOH), precipitates were obtained containing aragonite, brucite and magnesite as identified by XRD, TGA and SEM analysis techniques. The major finding of this work is that DS water is suitable environment to be used to sequester CO2.