Products Cited in Publications Worldwide Adsorption of Hydroxamic Acid Ligands for Improved Extraction of Rare Earth Elements from Monazite Ores

Adsorption of Hydroxamic Acid Ligands for Improved Extraction of Rare Earth Elements from Monazite Ores

Bryantsev, Vyacheslav S; Zhou, Muchu; Gibson, Luke D; Stamberga, Diāna; Popovs, Ilja; Einkauf, Jeffrey; Thiele, Nikki A; Sacci, Robert; Doughty, Benjamin; Bocharova, Vera

Abstract

Efficient separation of rare earth elements ores (REEs) via froth flotation requires the development of novel ligands with enhanced adsorption capacity and selectivity. To realize these advances, understanding the mechanisms underlying interactions between the ligand and mineral surfaces is essential. This study systematically evaluates the adsorption behavior of alkyl and aromatic alkyl-substituted ligands of hydroxamic acid on monazite surfaces using complementary spectroscopic techniques, including UV-visible (UV-vis) spectroscopy, Raman spectroscopy, infrared spectroscopy, and vibrational sum frequency generation (SFG) spectroscopy, together with the ab initio molecular dynamics (AIMD) simulations. Among the studied ligands, octanohydroxamic acid (OHA) and 4-ethoxy-N,2-dihydroxybenzamide (EDHBA) exhibite high adsorption capacity under basic pH (8-10) by forming multilayers on the surface. OHA has a higher equilibrium adsorption capacity compared to EDHBA, but it forms a less stable multilayer susceptible to disruption in the presence of interfering ions. AIMD results show that OHA adopts a single stable chelating geometry, while EDHBA exhibits multiple binding modes involving distinct interactions with La surface atoms and phosphate-bound oxygens, resulting in more complex adsorption kinetics. The variations in surface binding and intermolecular interactions observed between alkyl and aromatic molecules influence the differences in adsorption kinetics, equilibrium adsorption capacities on the mineral surface, and their flotation performance. This work provides valuable insight into the adsorption mechanism of ligands to mineral interfaces, which is crucial for guiding the design of new ligands with enhanced separation performance.

Keywords

monazite ; hydroxamic acid ligand ; spectroscopy ; adsorption ; kinetics ; isotherm ; ab initio molecular dynamic (AIMD)

Purchased from AmBeed

A103501631888-72-995%

N-Hydroxypicolinamide

191.0/250mg

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Octanohydroxamic acid

A1663107377-03-999%

Octanohydroxamic acid

30.0/100g

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