Distribution Pattern of Rare Earth Ions between Water and Montmorillonite and Its Relation to the Sorbed Species of the Ions

Takahashi, Yoshio; Tada, Akisa; Shimizu, Hiroshi

doi:10.2116/analsci.20.1301

Cited by 56 publications

(38 citation statements)

References 45 publications

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“…This pattern is similar to those observed for REE adsorption onto bacterial cell surfaces, 13 where phosphate sites in the bacterial cell surface were the binding sites of REEs, as indicated by an EXAFS analysis. 14 Given that the shape of the REE pattern depends on the relative variation in the stabilities of REEs to the ligands coordinating to REEs, 24,25 the REE pattern in the DNA-filter hybrid implies that the binding site in the material is also phosphate, as will be confirmed by EXAFS analysis.…”

Section: Adsorption Of Ree On the Dna-filter Hybridmentioning

confidence: 79%

Recovery and Separation of Rare Earth Elements Using Columns Loaded with DNA-filter Hybrid

et al. 2012

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Given that the supply of several rare earth elements (REEs) is sometimes limited, recycling REEs used in various advanced materials, such as Nd magnets, is important for realizing efficient use of REE resources. In the present work, the feasibility of using DNA for REE recovery and separation was examined, along with the identification of the binding site of REEs in DNA. In particular, a DNA-cellulose filter paper hybrid was prepared so that DNA-based materials can be used for the separation of REEs using columns loaded with DNA. N,N′-Disuccinimidyl was used as a cross-linker reagent for the fixation of DNA onto a fibrous cellulose filter. The results showed that (i) the DNA-filter hybrid has a sufficiently high affinity to adsorb REEs; (ii) the adsorption capacity was 0.182 mg/g for Nd; and (iii) the affinity of REEs for DNA was stronger for REEs with larger atomic numbers. The difference of the affinity among REEs in the third result was compared with the adsorption patterns of REEs discussed in the literature. The comparison suggests that phosphate in the DNA-filter paper hybrid was responsible for REE adsorption onto the hybrid. The results were supported by the Nd, Dy, and Lu LIII-edge EXAFS; the REE-P shell was identified for the second neighboring atom, showing the importance of the phosphate site as REE binding sites. The difference in the affinity among REEs suggest that group separation of REEs (such as La, Ce, (Pr and Nd), (Ho, Dy, and Er), (Tb and Gd), (Sm, Eu), Tm, Yb, and Lu) is possible, although complete isolation of each REE from a solution containing all REEs may be difficult. For practical applications, Nd and Fe(III) were successfully separated from a synthetic solution of Nd magnet waste using columns loaded with the DNAfilter hybrid.

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Section: Adsorption Of Ree On the Dna-filter Hybridmentioning

confidence: 79%

Recovery and Separation of Rare Earth Elements Using Columns Loaded with DNA-filter Hybrid

et al. 2012

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“…The first process is strongly influenced by ionic strength and does not depend on pH (Coppin et al, 2002;. On the contrary, pH conditions strongly influence surface complexation that occurs with an inner-sphere mechanism (Takahashi et al, 2004;. The chondrite-normalised patterns of YREEs in our seawater samples also suggest an important contribution to the YREE fractionation effects from the alteration of volcanic SPM (Fig.…”

Section: Dissolved Phasementioning

confidence: 67%

“…Evidence from alteration effects on the ash leached during the kinetic experiments suggest differential YREE sorption processes onto montmorillonite-type mineral surfaces that could explain the preferential removal of Y. This mechanism may be due to the preferential formation under alkaline pH conditions of Yttrium and OH À inner-sphere complexes onto particle edges of montmorillonite (Takahashi et al, 2004).…”

Section: Dissolved Phasementioning

confidence: 94%

“…Results from leaching experiments are generally reported for pure water (e.g., Mö ller and Giese, 1997;Bach and Irber, 1998;Bau et al, 1998), and adsorption processes are investigated in a solution of known composition (Coppin et al, 2002;Takahashi et al, 2004). In order to compare the results obtained from our leaching experiment with literature data, we favoured the use of a trace-element-free seawater.…”

mentioning

confidence: 88%

“…The behaviour of the dissolved YREEs in the presence of montmorillonite was investigated by Takahashi et al (2004), and Coppin et al (2002), although the latter authors excluded Yttrium from their investigation.…”

Section: Introductionmentioning

confidence: 99%

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Alteration effects of volcanic ash in seawater: Anomalous Y/Ho ratios in coastal waters of the Central Mediterranean sea

Censi

Sprovieri

Larocca

et al. 2007

Geochimica et Cosmochimica Acta

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This paper presents the results of a study based on data collected during the oceanographic cruise ANSIC 2001 carried out in the Ionian Sea during the explosive activity of Mount Etna in the summer of 2001. Anomalous low values of Y/Ho ratios in seawater suggest extensive scavenging processes on the surfaces of smectitic alteration products, with Y and Ho fractionation controlled by the differences in their electronic configurations and behaviour during solution/surface complexation equilibria. These processes can also be traced through the presence of significant tetrad effects recorded in the chondrite-normalised Rare Earth Elements and Yttrium (YREEs) patterns of suspended particulate matter. This suggests that the preferential Y scavenging from seawater is due to the formation of inner-sphere complexes with OH À groups on montmorillonite crystal surfaces. The preliminary results of kinetic experiments of YREE released from volcanic ash to coexisting seawater, and the related effects on Y/Ho ratios and Ce anomalies, are consistent with the fractionation of Light Rare Earth Elements (LREEs) with respect to Heavy Rare Earth Elements (HREEs) observed in dissolved phase. They suggest a behaviour of Y similar to that reported for LREEs, particularly for Ce and Pr.

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Waste Disposal in Clay Formations: Influence of Humic Acid on the Migration of Heavy‐Metal Pollutants

Kautenburger

Beck

2008

ChemSusChem

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The deep geological disposal of high-level radioactive waste is assumed to be a way of providing adequate protection for humans and the environment. For the safe isolation of radioactive waste, a low permeability and high sorption capacity of the geological barrier is important. Clay minerals play a major role in different concepts for the disposal of high-level nuclear waste in deep geological formations. Geological clay formations are considered to be a host rock for waste repository. [1] Natural clays can contain natural organic matter, for example, humic substances. In most aquatic systems, components of natural organic matter such as humic acids can act as ligands for complexing metal ions and may affect the speciation and thus the mobility of the metal.[2] By forming soluble complexes and colloids with numerous toxic heavy metals, including radioA C H T U N G T R E N N U N G nuclides, humic acids can influence the migration behavior of these pollutants in hematite [3] or geological clay formations, as reported, for example, for bentonite, [4] kaolinite, silica, and montmorillonite.[5] Kaolinite is a significant component of many soils and fracture-filling materials of crystalline hard rock. These clay formations are part of the natural barrier protecting the environment from the possible impact of radionuclide contamination.[6]Herein we report the sorption behavior of the trivalent lanthanides europium and gadolinium (as homologues of the actinides americium and curium), under conditions close to those of nature, in a binary system consisting of these heavy metals and well-crystallized kaolinite (KGa-1b) as a model mineral, and in the ternary system metal/kaolinite/humic acid. The influence of the concentration of lanthanide ion, pH value, or concentrations of different competing metal cations (water hardness, represented by calcium and magnesium) on the sorption of the lanthanide ion onto kaolinite in the presence or absence of humic acid was investigated. After the sorption experiments, free metal ions in the supernatant solution were analyzed by inductively coupled plasma mass spectrometry (ICP-MS). Speciation of the lanthanide-humic acid complexes are reported elsewhere.[7]The ternary system described in Figure 1 is most suitable to study metal migration under natural conditions. Research on the three binary systems can be seen as preliminary tests to understand partial aspects of the complete system. With humic acid, there is the possibility that metal humates could adsorb on the kaolinite surface through hydrophobic interactions, thus increasing retention of the lanthanide ion. Negatively charged complexes could inhibit sorption of the lanthanide and accelerate migration through clay minerals. Sorption behavior is strongly dependent on the experimental conditions as tests performed in the ternary system clearly show. The experiments that were performed here are based on the system metal/kaolinite with humic acid as an additional influencing factor.With humic acid present, the sorption of the lant...

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Distribution Pattern of Rare Earth Ions between Water and Montmorillonite and Its Relation to the Sorbed Species of the Ions

Cited by 56 publications

References 45 publications

Recovery and Separation of Rare Earth Elements Using Columns Loaded with DNA-filter Hybrid

Recovery and Separation of Rare Earth Elements Using Columns Loaded with DNA-filter Hybrid

Alteration effects of volcanic ash in seawater: Anomalous Y/Ho ratios in coastal waters of the Central Mediterranean sea

Waste Disposal in Clay Formations: Influence of Humic Acid on the Migration of Heavy‐Metal Pollutants

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