Malgorzata M. Lencka

Bioadsorption of Rare Earth Elements through Cell Surface Display of Lanthanide Binding Tags

With the increasing demand for rare earth elements (REEs) in many emerging clean energy technologies, there is an urgent need for the development of new approaches for efficient REE extraction and recovery. As a step toward this goal, we genetically engineered the aerobic bacterium Caulobacter crescentus for REE adsorption through high-density cell surface display of lanthanide binding tags (LBTs) on its S-layer. The LBT-displayed strains exhibited enhanced adsorption of REEs compared to cells lacking LBT, high specificity for REEs, and an adsorption preference for REEs with small atomic radii. Adsorbed Tb(3+) could be effectively recovered using citrate, consistent with thermodynamic speciation calculations that predicted strong complexation of Tb(3+) by citrate. No reduction in Tb(3+) adsorption capacity was observed following citrate elution, enabling consecutive adsorption/desorption cycles. The LBT-displayed strain was effective for extracting REEs from the acid leachate of core samples collected at a prospective rare earth mine. Our collective results demonstrate a rapid, efficient, and reversible process for REE adsorption with potential industrial application for REE enrichment and separation.

Vapour-liquid equilibrium in the 2-butanone - water system at 101.325 kPa

Abstract Vapour-liquid equilibrium in the title system was measured with special regard to concentration limits. The data of both regions were fitted to six different equations for the determination of the best values of limiting activity coefficients (11.53 and 5.58 for acetone and water, respectively). The densities of solutions at 25°C were determined in both boundary regions.

Thermodynamics of Multicomponent Perovskite Synthesis in Hydrothermal Solution

Publisher Summary This chapter focuses on the hydrothermal synthesis of smart ceramic materials with a perovskite-type structure. Perovskite compounds have the general formula ABO 3 , where the A cation is relatively large and of low valence and the B cation is relatively small . It presents modeling and experimental validation of selected hydrothermal systems. A thermodynamic model of heterogeneous aqueous electrolyte systems, coupled with a facility for the automatic generation of stability and yield diagrams, provides a powerful tool for predicting the effect of various process conditions on the synthesis of smart ceramic materials. In particular, it makes it possible to determine the optimum conditions for the synthesis of various perovskite-type materials from simple precursors. The model is particularly valuable for analyzing the effects of changing the chemical identity and relative amounts of starting materials as well as for predicting the possibility of contamination with carbonates. The theoretical predictions allow formulating synthesis guidelines. In order to validate the results of theoretical predictions, experimental syntheses were performed in the whole temperature and pH range and for various input amounts of starting materials.