Bench-Scale Simulation of the Real Chinese Salt Lake Environment to Achieve Lithium Ion Concentration And Osmotic Power Generation Through Ionic Equilibrium Concentration in the Forward Osmosis Process

Abstract

Salt lake brines with high osmotic pressures can be used as natural draw solutions (DS) for the Li+ concentration process in forward osmosis (FO). However, the problem of low Li+ concentrations (a few hundred milligrams per liter) has always prevented FO from being upscaled from the laboratory. Therefore, in this study, a bench-scale 0.5-1.5 g/L Li+ concentration process was carried out and had an equilibrium concentration of approximately 0.2 g/L on the DS side; this was utilized to achieve a low Li+ concentration process with a long cycle recovery of 94% and no attenuation. In addition, the focus of this study was on the effect of the operating conditions for the concentration process. The parameters included the temperature, flow rate, and initial feed solutions (FS) concentration. The temperature was varied between 0, 15, and 25 °C since the salt lake area in China is mostly a high-altitude and cold weather area. Moreover, this study proposes recycling the high osmotic pressure of DS from the Li+ concentration process of FO and developing a synchronized osmotic energy generation process. Our work lays the foundation for the FO Li+ concentration process in salt lake brine to move from the laboratory to large-scale production.

Keywords: forward osmosis, ionic equilibrium concentration, lithium ion concentration, bench scale