Selective Sorption of Ce3+ over La3+ Ions on Biogenic Manganese Oxides

2009 ◽  
Vol 71-73 ◽  
pp. 633-636 ◽  
Author(s):  
Keiko Sasaki ◽  
T. Kaseyama ◽  
Tsuyoshi Hirajima

Unique properties of biogenic Mn oxides were applied to a fundamental study of separation and recovery of rare earth elements. Selective sorption of Ce3+ over La3+ ions was achieved at neutral pH values using biogenic Mn oxides produced by Paraconiothyrium sp. WL-2 strain. The selective coefficient for Ce3+ (αCe) was much greater with biogenic and synthetic Mn oxides than those for La3+ (αLa). Ce3+ ions were oxidized to CeO2 by Mn(III, IV) in Mn oxides under anaerobic conditions resulting in the release of Mn2+ ions, while La3+ ions were sorbed without a redox reaction. With an increase in coexisting La3+ ions, sorption of Ce3+ on both Mn oxides was significantly suppressed, especially with synthetic Mn oxides. The edges of the structure are competitive sites because of fewer numbers of vacant sites in synthetic Mn oxide layers. The preferential sorption on the edge sites of Mn oxides is in the order of La3+ > Ce3+. These phenomena can be expanded to separation and recovery of other rare earth elements from natural and anthropogenic sources.

Minerals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 388
Author(s):  
Silvester Jürjo ◽  
Liis Siinor ◽  
Carolin Siimenson ◽  
Päärn Paiste ◽  
Enn Lust

Estonian phosphorite ore contains trace amounts of rare earth elements (REEs), many other d-metals, and some radioactive elements. Rare earth elements, Mo, V, etc. might be economically exploitable, while some radioactive and toxic elements should be removed before any other downstream processing for environmental and nutritional safety reasons. All untreated hazardous elements remain in landfilled waste in much higher concentration than they occur naturally. To resolve this problem U, Th, and Tl were removed from phosphorite ore at first using liquid extraction. In the next step, REE were isolated from raffinate. Nitrated Aliquat 336 (A336[NO3]) and Bis(2-ethylhexyl) Phosphate (D2EHPA) were used in liquid extraction for comparison. An improved method for exclusive separation of radioactive elements and REEs from phosphorite ore in 2-steps has been developed, exploiting liquid extraction at different pH values.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mariusz Sojka ◽  
Adam Choiński ◽  
Mariusz Ptak ◽  
Marcin Siepak

AbstractThe objective of this study was to analyse spatial variability of the trace elements (TEs) and rare earth elements (REEs) concentration in lake bottom sediments in Bory Tucholskie National Park (BTNP); Poland. The following research questions were posed: which factors have a fundamental impact on the concentration and spatial variability of elements in bottom sediments, which of the elements can be considered as indicators of natural processes and which are related to anthropogenic sources. The research material was sediments samples collected from 19 lakes. The concentrations of 24 TEs and 14 REEs were determined. The analyses were carried out using the inductively coupled plasma mass spectrometry (ICP-QQQ). Cluster analysis and principal component analysis were used to determine the spatial variability of the TEs and REEs concentrations, indicate the elements that are the indicators of natural processes and identify potential anthropogenic sources of pollution. The geochemical background value (GBV) calculations were made using 13 different statistical methods. However, the contamination of bottom sediments was evaluated by means of the index of geo-accumulation, the enrichment factor, the pollution load index, and the metal pollution index. The BTNP area is unique because of its isolation from the inflow of pollutants from anthropogenic sources and a very stable land use structure over the last 200 years. This study shows high variability of TE and REE concentrations in lake sediments. The values of geochemical indices suggest low pollution of lakes bottom sediments. It was found that TEs originated mainly from geogenic sources. However, the concentrations of Li, Ni, Sc, Se, Be, Se, Ag, Re, Tl, Cd, Sb and U may be related to the impact of point sources found mainly in the Ostrowite Lake. Almost all REEs concentrations were strongly correlated and their presence was linked to with geochemical processes. The elements allowing to identify natural processes and anthropogenic pollution sources were Cr, Co, Cu, Ag, Cd, Zn, Bi, Re, Ba, Al and Rb in TEs group and Nd, Gd, Yb, Lu, Eu, Dy and Ce in REEs group. The analysis shows high spatial variability of TE and REE concentrations in lake sediments. The values of geochemical indices point to low pollution of lakes sediments. The anthropogenic sources only for two lakes had an impact on concentrations of selected TEs and REEs. The analyses allowed to identify elements among TEs and REEs documenting geochemical processes and those indicating anthropogenic sources of pollution.


2011 ◽  
Vol 284-286 ◽  
pp. 2497-2500
Author(s):  
Lian Feng Gao ◽  
Peng Zhang ◽  
Ying Zhang ◽  
Zhen Guo Zhang ◽  
Chang Shui Liu

Polymetallic nodules/crusts are one of the most important mineral deposits in the ocean, in which iron, manganese, copper, cobalt, nickel and other metals are rich, and rare earth elements are rich, too. In this study, the contents of 11 rare earth samples in polymetallic nodules/crusts from the Pacific, Atlantic, Indian Ocean and north of the South China Sea are analyzed. The average content of rare earth in polymetallic nodules/crusts is 1265.57×10-6, the average content of nodules is 1096.96×10-6, and the average content of crust is 1623.88×10-6. The enrichment of rare earth elements is controlled by iron and manganese oxides and clay minerals in nodules/crusts, which could absorb rare earth elements from seawater and sediment. Ce elements are highly enriched, making polymetallic nodules/crusts become the first used rare earth elements in mineral development.


2010 ◽  
Vol 74 (19) ◽  
pp. 5463-5477 ◽  
Author(s):  
Kazuya Tanaka ◽  
Yukinori Tani ◽  
Yoshio Takahashi ◽  
Masaharu Tanimizu ◽  
Yoshinori Suzuki ◽  
...  

2012 ◽  
Vol 524-527 ◽  
pp. 408-412
Author(s):  
Zhen Guo Zhang ◽  
Chang Shui Liu ◽  
Lian Feng Gao ◽  
Ying Zhang ◽  
Guo Yuan Shi ◽  
...  

Polymetallic nodules are one of the most important sedimentary mineral resources in the ocean, in which iron, manganese, copper, cobalt, nickel and other metals are rich, and rare earth elements are rich, too. The samples are collected from the northwest continental margin of South China Sea (SCS). Their model show the similar appearance to the oceanic nodules which collected from the Pacific and Indian Ocean. They are big, regular shape and clear layers. But their geochemical characteristics show distinct difference with oceanic nodules.The samples formed by multiple millimeter-thick layers of Fe and Mn oxyhydroxides surrounding the nucleus composed of plastic marl and sediment. Massive, laminated, detrital and mottled to dendritic textural features were developed by the Fe and Mn oxyhydroxide layers.Based on the detailed study of the geochemistry and growth rate, the nodules may represent new-type ones which grow fastly in high sediment rates environment from the northwest continental margin of the SCS. The reason of the fast growth may be affected by the environmental fluctuations and the change of terrigenous sediments. Elements correlation of Mn-Fe-(Cu+Ni) suggests that the origin of the sample may be of hydrogenic. It may be show that these nodules are dominative of the special environment of the marginal sea which includes the geographical condition and the oceanic environmental factors. The average content of Rare Earth Elements (REEs) in these samples are much higher than those recorded in Earth’ crust and sedimentary rocks. The enrichment of rare earth elements is controlled by iron and manganese oxides and clay minerals in nodules, which could absorb rare earth elements from seawater and terrigenous sediment. Ce elements are highly enriched, making polymetallic nodules become the first used rare earth elements in oceanic mineral development.


2007 ◽  
Vol 20-21 ◽  
pp. 607-610
Author(s):  
Keiko Sasaki ◽  
M. Matsuda ◽  
T. Urata ◽  
Tsuyoshi Hirajima ◽  
H. Konno

Sorption of Co(II) on the biogenic Mn oxide produced by a Paraconiothyrium sp.-like strain was investigated. The biogenic Mn oxide, which was characterized to be poorly crystalline birnessite (Na4Mn(III) 6Mn(IV) 8O27 ·9H2O) bearing Mn(III) and Mn(IV) in the structure, showed approximately 6.0-fold higher efficiency for Co(II) sorption than a synthetic Mn oxide. XP-spectra of Co 2p for the biogenic and synthetic Mn oxides after Co(II) sorption indicate that Co was immobilized as Co(III) on the surface of Mn oxides, clearly suggesting that redox reaction occurs between Co(II) ions and each Mn oxides. The Co(II) ions would be initially sorbed on the vacant sites of the surface of biogenic Mn oxide, and then oxidized to Co(III) by neighbor Mn(III/IV) atoms to release Mn(II). For the synthetic Mn oxide, release of Mn(II) was negligibly small because the oxidant is only Mn(IV) in ramsdellite (γ-MnO2). The Mn(II) release from the biogenic Mn oxide during Co(II) adsorption would be not only from weakly bounded Mn(II), but also from redox reaction between Mn(III/IV) and Co(II) ions.


Atmosphere ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 694
Author(s):  
Clara Turetta ◽  
Matteo Feltracco ◽  
Elena Barbaro ◽  
Andrea Spolaor ◽  
Carlo Barbante ◽  
...  

This study presents the year-round variability of the water-soluble fraction of trace elements (wsTE) and rare earth elements (wsREE) among size segregated airborne particulate matter samples collected at Ny-Ålesund in the Svalbard Archipelago from 26 February 2018 to 26 February 2019. Six different aerosol dimensional fractions were collected using a multi-stage Andersen impactor to better understand local and global circulation with the aim of disentangling the source of inorganic tracers from specific natural or anthropogenic sources. The wsTE and wsREE content, especially in the finest fractions in remote areas, is primarily related to long-range transport and it gives valuable information on (1) the global circulation, (2) the natural sources and (3) the contribution of human activities to aerosol composition. A Factor Analysis was applied to the dataset, including levoglucosan and methanesulfonic acid (MSA), to assess the possibility of using certain inorganic tracers as indicators of specific transport events or circulation regimes. We also investigate back-trajectories to determine potential source areas.


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