A lithium selective adsorption composite by coating adsorbent on PVC plate using epoxy-silica hybrid binder

Abstract

The industrial demand for lithium especially in a battery is expected to be high in near future. The use of lithium selective adsorbents, such as spinel-type lithium manganese oxides (LMOs) show the potential candidates for recovery of lithium from seawater. Here we report the approach for recovery of lithium from seawater using a new composite composed of LMO and epoxy-silica hybrid binder (HB) prepared by sol-gel method. The LMO and HB composites were coated on polyvinyl chloride (PVC) plate and its adsorption efficiency was studied in terms of binder contents and thickness. The composite showed excellent physicochemical and mechanical durability in seawater. The adsorption capacity of 6.5 mg/g (67% in comparison to that by powder LMO) was obtained in natural seawater when the composition of HB/LMO was 30/70 (in dry wt%) at a thickness of 300 μm. The kinetic study showed that the lithium adsorption on composite obtained using 30 mg/L Li spiked seawater was found to be matched to pseudo-second order model as the coating thickness was <230 μm, and turned to follow intra particle model over 230 μm due to diffusion limit of lithium ion into the inside of coated adsorbent. The results displayed good reproducibility over 5 consecutive adsorption/desorption cycles without significant efficiency drop. The results suggest that the composite tested in this study has good feasibility in practical application to seawater on large scale.