Lanthanum immobilization by iron and aluminum colloids

Pietralonga, Aloncio Gottardo; Mendonça, Bruno Araújo Furtado de; Barcelos, Gisely Souza; Mello, Jaime Wilson Vargas de; Abrahão, Walter Antônio Pereira

doi:10.1007/s12665-017-6583-z

Cited by 9 publications

(18 citation statements)

References 38 publications

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“…Bands corresponding to poorly crystalized lepidocrocite were detected at higher amount of Eu, but the intensities decreased as Al increases. Such results agree with the study of Pietralonga et al (2017) that showed the increasing in lanthanum contents favour the precipitation of lepidocrocite, in addition to lanthanite. Goethite peaks are more prominent in the absence of Al at low amounts of Eu, which is not evident for Ho, but the intensities for magnetite peaks were higher in the presence of Ho than in the presence of Eu.…”

Section: Acid Leaching Reducible and Oxidisable Phasessupporting

confidence: 92%

“…It is worth of note that the high efficiencies of the treatments were comparable to previous studies irrespective to incubation period and pH. Pietralonga et al (2017) for example, incubated their treatments of La contaminated water for 90 days, compared to a 60-day period in this study for Eu and Ho. It is also relevant to compare the adopted pH's for precipitations.…”

Section: Immobilization Of Eu and Ho From Aqueous Solution By Co-precsupporting

confidence: 84%

“…On the other hand, isomorphic substitution of Fe by Al drives precipitation of goethite (Gt), since this mineral is able to incorporate more structural Al than magnetite (Schwertmann and Murad 1990). Increasing amounts of Al also favoured precipitation of gibbsite (Al(OH)3) and lepidocrocite (FeOOH), as also observed by Pietralonga et al (2017).…”

Section: Mineralogical Characterization Of Precipitated Phasesmentioning

confidence: 93%

“…To test the hypothesis that the REE molar ratios affect their removal from water and the mineralogical phases co-precipitated with Fe/Al (hydr)oxides, different REE proportions were used in treatments. The absence of REE (blanks) was not considered in any experimental set due to: a) previous studies revealed precipitation of magnetites and goethites from Fe(II) salts, respectively in the absence and presence of Al (Mello et al 2018;Pietralonga et al 2017;Barcelos 2014;Cardoso 2014) and hematite from Fe(III)…”

Section: Experimental Setsmentioning

confidence: 99%

“…The use of Al aimed to evaluate its effects in the stability of co-precipitated phases (Barcelos et al 2018a;Pietralonga et al 2017;Silva et al 2010;Jeanroy et al 1991;Schwertmann 1984). Values considered for pH were 9.0 (six treatments) and 6.0 (four treatments), consistent with the range allowed for effluents discharge in Brazil (5.0 to 9.0) according to Resolution 430 of the Brazilian Environmental National Council (CONAMA, 2011).…”

Section: Experimental Setsmentioning

confidence: 99%

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Removal of lanthanum, cerium, europium and holmium from water by co-precipitation with iron and aluminium (hydr)oxides

Barcelos¹

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Effluents from mining activities may have high concentrations of trace elements such as arsenic, rare earth elements (REE) and actinides, mainly in areas where acid mine drainage (AMD) occurs. Use of lime to neutralise AMD also promote co-precipitation of iron (Fe) and aluminium (Al) (hydr)oxides, increasing the removal of trace elements from water. This study aimed to evaluate the efficiency of Fe/Al (hydr)oxides co-precipitation to remove lanthanum (La), cerium (Ce), europium (Eu) and holmium (Ho) from water under laboratory conditions. Two sets of experiments were performed with individual REE solutions containing Eu and Ho. In these cases, Fe(II) and Al sulphates were used at different Fe:Al:REE molar ratios. Two other sets of experiments with Fe(II) and Fe(III) sulphates were performed in a mixed REE solution containing La, Ce, Eu and Ho. To coprecipitate Fe/Al (hydr)oxides, pH's were raised to 9.0 and 6.0 with 5 mol L-1 KOH solution. Soluble contents of Fe, Al and REE were periodically measured in supernatants aliquots. Precipitates were collected at the end of the 60-day incubation period and, then, oven-dried, sieved and characterised by X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis. The stability of REE in precipitates was also assessed by BCR sequential extractions. All treatments presented high REE removal efficiency from water at pH 9.0, but significantly lower at pH 6.0 for Fe(II) treatments. Magnetite precipitation was favoured by lower contents of REE and Al, whereas goethite and lepidocrocite were favoured at higher contents. Segregated phases were not detected for Eu and Ho, but lanthanite and cerianite precipitated at high amounts of La and Ce, respectively. For mixed REE treatments, the mineralogical phases precipitated were mostly poorly crystallised. The presence of magnetite was associated to higher REE stabilities, whereas lepidocrocite decreased the stability as measured by BCR extractions. The presence of segregated phases as cerianite resulted in increased Ce stability, but presence of lanthanite decreased La stability in precipitates.

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Section: Acid Leaching Reducible and Oxidisable Phasessupporting

confidence: 92%

Section: Immobilization Of Eu and Ho From Aqueous Solution By Co-precsupporting

confidence: 84%

Section: Mineralogical Characterization Of Precipitated Phasesmentioning

confidence: 93%

Section: Experimental Setsmentioning

confidence: 99%

Section: Experimental Setsmentioning

confidence: 99%

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Removal of lanthanum, cerium, europium and holmium from water by co-precipitation with iron and aluminium (hydr)oxides

Barcelos¹

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Immobilization of Eu and Ho from synthetic acid mine drainage by precipitation with Fe and Al (hydr)oxides

Barcelos

Veloso

Mello

et al. 2018

Environ Sci Pollut Res

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Use of lime to mitigate acid mine drainage is, in general, accompanied by precipitation of iron (Fe) and aluminium (Al) (hydr)oxides which may increase the removal of trace elements from water. This work aimed to evaluate the precipitation of Fe/Al (hydr)oxides to remove rare earth elements (REE) from contaminated water and the stability of precipitates. Two sets of 60-day syntheses were carried out using different Fe/Al/REE molar ratios, for europium (Eu) and holmium (Ho). The pH was periodically adjusted to 9.0, and the stability of the resulting precipitates was evaluated by water-soluble and BCR extractable phases, namely (1) acid soluble, extracted by 0.11 mol L acetic acid; (2) reducible, extracted with 0.5 mol L hydroxylamine hydrochloride; and (3) oxidisable, extracted with 8.8 mol L hydrogen peroxide efficiencies of the water treatments for both Eu and Ho that were higher than 99.9% irrespective to the Fe/Al/REE molar ratios. Water-soluble phases of Eu and Ho were lower than 0.01% of the total contents in the precipitates. Recoveries from precipitates by Bureau Communautaire de Référence (BCR) sequential extractions increased with increasing concentrations of Eu and Ho. Acetic acid extracted higher amounts of REE, but Eu recovery was superior to Ho. Lepidocrocite was formed as Eu concentration increased which decreased its stability in the precipitates.

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