Arsenite removal from contaminated water by precipitation of aluminum, ferrous and ferric (hydr)oxides

Vasques, Isabela C.F.; Mello, Jaime Wilson Vargas de; Veloso, Renato Welmer; Ferreira, Vanessa de P.; Abrahão, Walter Antônio Pereira

doi:10.1007/s11356-018-1458-8

Cited by 10 publications

(17 citation statements)

References 35 publications

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“…Actually, precipitates with Al were less stable than precipitates in Al absence (Table 4). Different results were found for arsenite [As(III)], which showed that Al enhanced the stability of precipitates from Fe(II) treatments (Vasques et al, 2018).…”

Section: Resultsmentioning

confidence: 99%

Effectiveness of Ferric, Ferrous, and Aluminum (Hydr)Oxide Coprecipitation to Treat Water Contaminated with Arsenate

et al. 2018

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Coprecipitation of Fe and Al (hydr)oxides has been considered a low‐cost process to remove As from wastewater. Arsenate is the most stable form of As in aerobic environments such as surface water, soils, and sediments and can be removed from water through methods based on this process. Iron/aluminum molar ratios of 100:0, 80:20, and 60:40 were used to treat water contaminated with As at concentrations of 50 and 500 mg L−1. Aluminum, ferrous, and ferric sulfates were used to coprecipitate Al and Fe (hydr)oxides at high pH. Maghemite, magnetite, lepidocrocite, and goethite were detected in precipitates from Fe(II), whereas hematite and ferrihydrite were identified in Fe(III) treatments. Segregation of Al (hydr)oxides as gibbsite and bayerite as well as the Al isomorphic substitution in Fe (hydr)oxides were detected in the presence of Al. The precipitates were classified as nonhazardous according to the leaching test based on Brazilian Technical Standard NBR 10005. The presence of Al increased the stability of the sludge from Fe(II) treatments but did not affect the stability of precipitates from Fe(III) treatments. High efficiencies for As removal from water were obtained for all treatments, but concentrations of soluble As were, in general, lower for Fe(III) treatments especially, in the absence of Al. Treatments were efficient in reaching the threshold to effluent discharge (0.5 mg L−1), but only treatments with initially 50 mg L−1 of As reached the threshold for drinking water (10 μg L−1). Core Ideas Up to 500 mg L−1 of arsenate in water could be removed with coprecipitation. Sludge from coprecipitation of As with Fe and Al (hydr)oxides is safe to dispose. Fe (III) is better than Fe (II) to remove soluble As at higher concentrations.

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Section: Resultsmentioning

confidence: 99%

Effectiveness of Ferric, Ferrous, and Aluminum (Hydr)Oxide Coprecipitation to Treat Water Contaminated with Arsenate

et al. 2018

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“…All these authors dealt with co-precipitation of trace elements with Fe/Al (hydr)oxides from Fe(II) salts. Vasques et al (2018), however, did similar studies of As co-precipitation with Fe/Al (hydr)oxides, from both Fe(II) and Fe(III) salts. Their results revealed that Al increases the As stability only in precipitates from Fe(II) treatments.…”

Section: Stability Of Precipitatesmentioning

confidence: 70%

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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“…A coprecipitação ocorre quando diferentes elementos em solução precipitam simultaneamente (Ford, 2012;. Este processo se revelou altamente eficaz para a remoção de elementos-traço de soluções contaminadas através da coprecipitação com óxidos de ferro e alumínio Vasques et al, 2018aVasques et al, , 2018b.…”

Section: Introdução Geralunclassified

“…A mobilidade dos elementos-traço e a estabilidade dos óxidos de ferro coprecipitados podem ser avaliadas através de métodos de extração que simulam diferentes condições ambientais. Procedimentos de extrações sequenciais e testes de bioacessibilidade são métodos de custo relativamente baixo que indicam mecanismos de sorção e força de ligação entre elemento-traço e fase mineral Vasques et al, 2018a).…”

Section: Introdução Geralunclassified

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Sorption and stability of trace elements on aluminum-substituted iron oxides

Cardoso

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The trace elements arsenic (As), antimony (Sb), lead (Pb), and cadmium (Cd) are present in orogenic gold deposits positively correlated with gold. Others, such as the rare earth elements lanthanum (La) and ytterbium (Yb), do not present correlation with gold. The weathering of these rocks, intensified by mining activity, leads to a redistribution throughout the local drainage basin. Iron oxides precipitating from weathering products immobilize part of these elements. High contents of gold in secondary deposits attract artisanal mining (garimpo), which historically contaminates watercourses with mercury (Hg). In this study, iron oxides were precipitated from a solution containing As, Pb, Sb, Cd, La, Yb, and Hg in the presence and in the absence of aluminum (Al). The stability of the coprecipitates was evaluated through BCR and SBET extraction procedures. Most of the initial content of As, Pb, Yb, and Sb was coprecipitated with Fe-oxides in only two hours, while Cd and La persisted longer in solution. Aluminum isomorphic substitution in Fe-oxides favored La and Yb immobilization in the short- term, but favored As and Cd immobilization in the long-term. Goethite with Al substitution (Al-goethite) was the only phase identified in treatments with Al, and lepidocrocite precipitation was favored at high concentrations of trace elements. Arsenic and Cd were more stable coprecipitated with Al-goethite. On the other hand, La and Yb were more stable with Al- free-goethite or lepidocrocite. The extraction percentages of As, Cd and Sb from precipitates were lower than Pb, La and Yb, which might be related to higher incorporation of As, Cd and Sb into the oxides structure. The precipitates had high bioaccessible contents of As and, therefore, higher risk to oral exposure for children (HQ > 1). Mercury did not interfere with other elements sorption or stability, therefore the hypothesis that garimpo can remobilize other elements through desorption from Fe-oxides due to Hg introduction was not confirmed. The results were useful for enhancing comprehension of interactions between iron oxides and trace elements in natural systems, including aspects such as sorption mechanisms, stability, bioavailability, and toxicity. Keywords: Coprecipitation. Acid mine drainage. Garimpo. Arsenic. Goethite.

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Arsenite removal from contaminated water by precipitation of aluminum, ferrous and ferric (hydr)oxides

Cited by 10 publications

References 35 publications

Effectiveness of Ferric, Ferrous, and Aluminum (Hydr)Oxide Coprecipitation to Treat Water Contaminated with Arsenate

Effectiveness of Ferric, Ferrous, and Aluminum (Hydr)Oxide Coprecipitation to Treat Water Contaminated with Arsenate

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

Sorption and stability of trace elements on aluminum-substituted iron oxides

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