Resources recovery-rubidium recovery from desalination brine through hydrometallurgy techniques

Abstract

Because of the water scarcity in many regions, different methods have been implemented to address this problem. The desalination technique is known as a practical solution among them. However, brine from the desalination process, which contains high concentrations of salts, minerals, and chemicals, will cause environmental harm to the sea, soil, and groundwater if it is not properly treated. Therefore, recovering critical resources from brine is essential for reducing brine disposal. This study aims to apply two hydrometallurgy systems, namely ion exchange and ionic liquid extraction, to circulate rubidium resources from brine. Dowex G26 resin was employed in the ion exchange system, and the adsorption isotherm model and saturated adsorption capacity were explored initially. The optimal parameters such as pH value, L/S ratio (liquid/solid), adsorption period, and adsorption temperature will then be investigated. In the ionic liquid extraction process, the t-BAMBP/C2mimNTf2 system (4-tert-Butyl-2-(α-methylbenzyl) phenol/1-ethyl-3-methylimidazolium bis(trifluoromethyls​ulfonyl)​imide) was used, and the parameters including pH value, concentrations of t-BAMBP, (O + I)/A ratio (organic + ionic liquid/aqueous), extraction time, and extraction temperature will be optimized as well. The results reveal that adsorption capacity and extraction efficiencies were 14.3 mg g− 1 and 86%, respectively. Furthermore, suitable reagents, including HCl and HNO3, were applied to desorb and strip rubidium from the Dowex G26 and t-BAMBP/C2mimNTf2 systems. To sum up, environmental hazards of desalination brine and rubidium resources can be reduced and recovered through the two different extraction systems.