Abstract
Adsorption with granules is critical for lithium recovery from brines due to the simplicity, efficiency, and environmental-friendliness of its industrial process. However, obtaining hydrophilic and stable binders remains to be a challenging task. Herein, a one-pot green strategy for granulating Li1.33Mn1.67O4 (LMO-1) powder into PVA/LMO-1 composites was developed with hydrophilic poly(vinyl alcohol) (PVA) as a binder and glycidoxypropyltrimethoxysilane (GPTES) as a coupling agent. Hydrogen peroxide (H2O2) was added to the reaction process to create pores by its thermal decomposition. The powder in the coupling composites would be difficult to leach out when compared to the granulation method of physical blending. Furthermore, the resulting PVA/LMO-1 demonstrated high water absorbency, pH stability, and fast water/ion exchange without visible swelling, which are important in industrial scale-up experiments where energy consumption and time can be reduced. Additionally, the selectivity of different ions of granulated PVA/LMO-1 was evaluated and confirmed. The lithium adsorption efficiency in real brine (produced water from the Puguang gas field) was 93.5%, which is higher than that of other adsorbents with comparable adsorption capacity; Meanwhile the magnesium-lithium ratios (Mg2+/Li+ ratios) decreased from 8.92 to 0.15, Na+/Li+ ratios decreased from 997 to 1.35, K+/Li+ ratios decreased from 30.26 to 0.29, Ca2+/Li+ from 30.87 to 2.36, indicating that the high salt content and organic pollutants of real bine do not affect the performance of the adsorbent. Long-term cyclic results showed that the structure and adsorption capacity of PVA/LMO-1 were stable. All these properties demonstrate that the developed PVA/LMO-1 absorbent could provide an appealing and competitive method for the industrial process.
Published Version
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