Application and limitations of a H2TiO3 - Diatomaceous earth composite synthesized from titania slag as a selective lithium adsorbent

The lithium adsorption properties of H2TiO3 synthesized from titania slag and immobilized on diatomaceous earth was investigated. Batch adsorption studies using a LiCl buffered solution (pH = 9.5) shows a maximum adsorption capacity of 27.4 mg/g. Isotherm and kinetic studies indicate that lithium adsorption takes place heterogeneously via a chemisorption mechanism. When tested in a low-grade lithium brine (i.e., The Great Salt Lake, Utah, USA (Li+ similar to 20 mg/L)), the adsorbent composite demonstrated high selectivity towards lithium over magnesium and sodium (selectivity factor > 40) with good recyclability at room temperature. However, despite its relatively high adsorption capacity in a buffered solution, the adsorption capacity and the rate of lithium adsorption drastically decreases in brine solution compared to the buffered solution due to the release of H+ ions during ion-exchange. The lithium adsorption capacity decreased with increasing temperature due to the loss of adsorption sites, which is a result of the hydrolysis of metastable H2TiO3 at higher temperatures. This decomposition of the adsorbent is a result of the destabilizing effect of H2TiO3 on DE.

Automated summary

The lithium adsorption capacity of H2TiO3 immobilized on diatomaceous earth is greatly influenced by temperature and solution composition, with a significant decrease in capacity and rate observed in brine solution containing sodium hydroxide. However, the composite material shows high selectivity and recyclability in lithium brines, indicating its potential for lithium recovery applications.