Recovery of Alkaline Earth Metals from Desalination Brine for Carbon Capture and Sodium Removal

Abstract

Because carbon dioxide adsorbs the radiation from the Sun and the Earth’s surface, global warming has become a severe problem in this century. Global warming causes many environmental problems such as heatwave, desertification, and erratic rainfall. Above all, erratic rainfall makes people have insufficient freshwater. To solve this problem, desalination technology has been developed in many countries. Although desalination technology can provide freshwater, it produces brine as well (producing 1 L of freshwater would result in 1 L of brine). The brine will decrease the dissolved oxygen in the sea and affect the organism’s habitat. In this study, magnesium and calcium from desalination brine were recovered in the form of magnesium hydroxide and calcium hydroxide by adjusting the pH value for carbon capture and sodium removal. Magnesium hydroxide would turn into magnesium carbonate through contacting CO2 in saturated amine carriers. Calcium hydroxide was added to the brine and reacted with CO2 (modified Solvay process). Sodium in brine would then be precipitated in the form of sodium bicarbonate. After removing sodium, brine can be released back into the ocean, or other valuable metals can be extracted from brine without the side effect of sodium. The results revealed that 288 K of 3-Amino-1-propanol could capture 15 L (26.9 g) of CO2 and that 25 g/L of Ca(OH)2 at 288 K was the optimal parameter to remove 7000 ppm sodium and adsorb 16 L (28.7 g) of CO2 in the modified Solvay process. In a nutshell, this research aims to simultaneously treat the issue of CO2 emission and desalination brine by combining the amines carrier method and the modified Solvay process.

Evaluation of the Purity of Magnesium Hydroxide Recovered from Saltwork Bitterns

“…Overall, results of the Margi (Figure 5) and Galia (Figure 6) precipitation tests confirmed that >99.9% Mg 2+ recovery can be achieved from artificial and real bitterns employing over-stoichiometric NaOH solutions in accordance with data reported in the literature [13,21,25,36].…”

“…The brines contained 2.84 g/L of Mg 2+ , which was recovered via precipitation in the form of MH. In the last decade, increasing interest has been placed on seawater desalination [11][12][13] and the high magnesium content in lake brines, as in the case of the Uyuni salar (Bolivia), which is one of the largest sources of lithium and also contains 15-18 g/L of Mg 2+ [14,15].…”

Total Resource Circulation of Desalination Brine: A Review

“…The reactions of using Ca(OH) 2 , KOH, and Al(OH) 3 to conduct the Modified Solvay Process are listed in Equations ( 7) to (9). [63][64][65][66] M. H. El-Naas et al directly added CaO to the bubble column reactor, which converts to calcium hydroxide as soon as it contacts the brine. The results revealed that CO 2 capture of 99% and Na production rate of 35% were achieved under 20 g L −1 of CaO, 10 °C, 13 wt% of NH 4 HCO 3 , and a gas flow rate of 500 mL min −1 .…”

“…Ca(OH) 2 -based [ 64] 0.6 mol L −1 brine 45% >11 15 °C 1 b a r -KOH-based [ 66] 0.5 g g −1 KOH 45.6% 13.6 50 °C 2 bar 776 mL min −1 KOH-based [ 67] 0.58 g g −1 KOH 44.1% >13 10 °C 2.1 bar 848.5 mL min −1…”

Resources recovery—Separation and recovery of copper from desalination brine through Lewatit TP 207 resin

“…Moreover, extracting metals from brine can assist in achieving the United Nations (UN) sustainable development goals, such as “Clean water and sanitation (SDG 6)” and “Life below water (SDG 14) (Herrera, 2019; Schmidt et al, 2017). ” According to the above narrative, some metals have already been recovered from desalination brine and employed for further application in our former research (Chen et al, 2020; Lee, Chen, & Chen, 2021; Lee, Chen, & Wu, 2021).…”