Biosorption of rare earth elements from aqueous solutions and their mineralization by microscopic fungi
L. P. SHUMILOVA1, V. I. RADOMSKAYA1, L. M. PAVLOVA1, N. Yu. LEUSOVA1, V. V. IVANOV2
1Institute of Geology and Nature Management Far East Branch Russian Academy of Sciences, Blagoveshchensk, Russia 2Far East Geological Institute Far East Branch of the Russian Academy of Sciences, Vladivostok, Russia
Keywords: biosorption, microscopic fungi, rare earth elements
Abstract
Biosorption is a promising method for preventing REE migration in natural environments and for their purification, and microscopic fungi are considered effective biosorbents. The article is devoted to studying the biosorption capacity of soil microscopic fungi in relation to REE in aqueous solutions. The dyna`mics of adsorption was studied using the example of lanthanum by the biomass of micromycetes Penicillium canescens and Talaromyces funiculosus depending on the contact time and its concentration in the solution. It was found that adsorption equilibrium in the fungal biomass - aqueous lanthanum solution system occurs within 24 hours, the T. funiculosus biomass demonstrated a higher sorption capacity. Lanthanum adsorption is more intense at medium acidic pH values of solutions; the maximum lanthanum sorption for 24 hours was noted at pH 3.1 by P. canescens biomass. It was revealed that REE with larger ionic radii are extracted more effectively, they more actively occupy free sorption centers with the formation of complexes. With prolonged interaction of REE with fungal biomass, nanoparticles are formed, the composition of which is close to monazite. According to IR spectroscopy data, the REE sorption centers are amide, carboxyl, amine and phosphate groups of the fungal cell wall. The presence of many ionogenic groups determines the high sorption capacity of the fungal cell wall. Intermolecular modeling of the interaction of lanthanum with amino acid residues of fungal cell wall proteins revealed that proteins form strong complexes by complex formation of REE with amino acid residues, where the active centers are glutamic and aspartic amino acids.
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